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| REVIEW ARTICLE |
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| Year : 2022 | Volume
: 45
| Issue : 3 | Page : 107-120 |
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Evolution of beryllium safety standards over the last 70 years and challenges ahead
Munish Kumar1, Alok Srivastava2
1 Industrial Hygiene and Safety Section, Health, Safety and Environment Group, Bhabha Atomic Research Centre; Department of Physical Sciences, Homi Bhabha National Institute, Mumbai, Maharashtra, India
2 Industrial Hygiene and Safety Section, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| Date of Submission | 18-Feb-2023 |
| Date of Decision | 17-Mar-2023 |
| Date of Acceptance | 20-Mar-2023 |
| Date of Web Publication | 18-May-2023 |
Correspondence Address:
Munish Kumar
Industrial Hygiene and Safety Section, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai 400 085, Maharashtra
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/rpe.rpe_6_23
Beryllium (Be), its alloys, and ceramics are widely used in high-tech applications such as electronics, space, atomic energy, and other day-to-day items of use. Initially, Be-based phosphors such as ZnBeSiO4 were being used in the lamp industry during the 1930s onward but were soon abandoned due to lung-related diseases and deaths of workers in the phosphor industry which was attributed to the highly toxic nature of Be. Typical effects associated with Be inhalation are chronic and acute Be diseases (CBD and ABD) and the main target organ being affected is the lung although effects on other human body organs are also well documented. Such diseases were observed not only in occupational workers handling Be but also in the members of the public residing in the neighborhood of Be manufacturing and processing facilities, especially in the USA. The CBD in occupational workers may depend on many factors such as individual's sensitivity to Be, amount of Be exposure, nature of Be compound, and types of Be operations and processes being performed. All this led to safety concerns about the toxicity of Be and recommendations regarding Be air concentration in the workplace and public environment were issued by the Department of Energy, USA in 1949 as occupational exposure limit (OEL)/threshold limit values (TLVs) which were 2.0 μg/m3 and 0.01 μg/m3 for occupational Be workers and public environment, respectively. It is worth to mention that these recommendations were adopted by various countries and organizations either as it is or with small changes. Later, different organizations recommended changes in the value of TLV for occupational workplaces, but such changes were never adopted as they were lacking sound epidemiological basis. The OEL/TLV of 2.0 μg/m3 continued for nearly 70 years until Occupational Safety and Health Administration (OSHA) in 2017 reduced the Be air concentration (BeAir-Conc) limit for occupational workers to 0.20 μg/m3 as the value of 2.00 μg/m3 was inadequate to protect occupational workers from CBD. This is a major change in the Be-related safety standards recommended recently and is/being adopted by many countries. The present article provides details about the evolution of Be safety standards over the last 70 years, the notion behind the recent revision of Be permissible exposure limit (PEL) value from 2.0 μg/m3 to 0.20 μg/m3 by OSHA and the associated safety challenges ahead. The information from literature about Be safety and related safety standards adopted in India is also given. The article also provides details about TLVs for BeAir-Conc being followed in various countries in the world and various challenges for the implementation of a revised PEL value of 0.20 μg/m3 as suggested by OSHA i.e., reduction in PEL value by a factor of 10 or recommendation of revised TLV of 0.05 μg/m3 by American Conference of Governmental Industrial Hygienists as compared to the previous value of 2.0 μg/m3. In view of different notations and limits for BeAir-Conc recommended by various agencies and limited information about Be safety-related details, all relevant information regarding Be safety along with the evolution of Be safety standards over the last 70 years is included in the present article. This is an important issue for the safety of individual's at occupational workplaces as well as for environmental safety and its compilation was highly needed for providing comprehensive information on Be safety from the inception of standards to till today.
Keywords: Beryllium safety standards, chronic beryllium disease and acute beryllium disease, threshold limit value, Be air concentration and surface contamination limits
How to cite this article:
Kumar M, Srivastava A. Evolution of beryllium safety standards over the last 70 years and challenges ahead. Radiat Prot Environ 2022;45:107-20 |
How to cite this URL:
Kumar M, Srivastava A. Evolution of beryllium safety standards over the last 70 years and challenges ahead. Radiat Prot Environ [serial online] 2022 [cited 2023 Jun 2];45:107-20. Available from: https://www.rpe.org.in/text.asp?2022/45/3/107/377235 |
| Introduction | |  |
Beryllium (Be) is considered one of the most chemically toxic element of the periodic table. Comprehensive information on its chemical toxicity and other adverse effects on humans became available after the appearance of lung and skin-related diseases and deaths among fluorescent lamp (BeO4SiZn - Be Zinc Silicate) manufacturing workers handling Be-based compounds which highlighted its toxicity and the use of Be-based compounds in lamp industry was later discontinued.[1],[2],[3],[4] However, because of certain special properties of Be and its alloys, it is being extensively used in nuclear, space, and industrial applications as well as in other items of day-to-day use. The appearance of hazards of Be exposure immediately after its use in the lamp industry, BeO manufacturing plants, and other industrial applications led to the need of some safety standards for the protection of occupational workers and the public environment.[5],[6] In the present article, the focus is mainly on Be-related biological effects and various safety standards adopted for Be handling and associated aspects that evolved in more than the last 70 years. Typical information on the approach to define chemical toxicity-related guidance or limit values along with associated response models adopted for humans from Be exposures is also included.
| Philosophy for Safety Standards of Toxic Chemicals-Primitive Information | | |
Hazardous chemicals are considered to follow the threshold model as far as chemical toxicity is concerned. It is believed that below the threshold (certain dose of chemicals), no observable harmful effects are likely to appear even after repeated day-by-day exposures over the entire working lifetime of about 40 years or so. In view of this, there is a certain dose below which no hazardous effects of chemicals are observed and this has led to the concept of threshold limit value (TLV), permissible exposure limit (PEL), recommended exposure limit (REL) as recommended and adopted by various agencies such as American Conference of Governmental Industrial Hygienists (ACGIH), Occupational Safety and Health Administration (OSHA), and National Institute for Occupational Safety and Health (NIOSH).[7],[8],[9],[10] It is important to mention that initially the term occupational exposure limit (OEL) was used in literature for workplace/occupational workers and is still popular with the scientific community. [Table 1]a further gives details about such terms as recommended by various agencies.[7],[8],[9],[10]
It is worth to mention that the TLV or PEL are time-weighted average over 8 h workers shift and methodologies to calculate TLV or PEL for exposure conditions deviating from recommended 8 h average are reported in the literature. Similarly, methodologies for the calculation of modified TLV or PEL for the mixture of chemicals affecting common target organs have also been recommended. It is to be noted that TLV or PEL are generally in parts per million (ppm) or mg/m3 or μg/m3 for gases or in air concentration and are convertible to each other. However, for the dust of chemicals, particulate matter, etc., mg/m3 or μg/m3 are popular for air concentration instead of ppm. It should be noted that even for radioactive materials such as uranium, TLV, or PEL are defined in mg/m3 or μg/m3 in air.[11] In addition, the short-term exposure limit (STEL) also called peak concentration to which occupational workers can be safely exposed is also defined for many chemicals and is generally average over 15 minutes and is intended to protect occupational workers from short-duration or peak exposures from hazardous chemicals.[7],[8],[9],[10]
It is worth mentioning that the application of the threshold model for chemical toxicity indicates that the toxic or hazardous effects in humans due to biological effects of chemical's or their toxicity are non-stochastic in nature and are popularly called as deterministic effects. It means that chemical's induced biological changes, damages, the killing of cells, or other effects in human organs occur after a certain amount of chemical's intake/dose i.e., via inhalation or ingestion, etc. By considering, various threshold dose or concentration values up to which no adverse effects appear are popularly called no observed adverse effect level (NOAEL).[12],[13],[14],[15] For NOAEL, the highest amount/concentration of a substance causes almost no detectable adverse effect. Similarly, the amount or concentration of chemicals which leads to the lowest observed adverse effect level (LOAEL) is also defined many times. However, such studies on NOAEL or LOAEL are mainly from animal experiments or from the interpretation of previous data pertaining to accidental or workplace exposure of humans.[12],[13],[14],[15] Further, NOAEL can be obtained from LOAEL value by applying appropriate conservative safety factors. It should be noted that the adverse effects and appropriate threshold limits or guideline values can be assigned from NOAEL or LOAEL values or a combination of both with further judgment, justification, assumptions, and approximations which forms the basis for the adoption of TLV, PEL, REL or OEL values in the work environment. It must be noted that the biological effects of chemicals are not observable below a certain threshold concentration or value leading to the applicability and adoption of threshold model of response for various chemicals i.e., below threshold concentration, no adverse health effects are likely to be observed in the majority of persons exposed up to a certain concentration.[12],[13],[14],[15]
However, certain chemicals such as Be are proven or probable carcinogens and may lead to the induction of cancer in humans. For such chemicals, the cancer induction is probabilistic without any dose/exposure threshold and linear nonthreshold model of dose/exposure-response is applicable. Further threshold effects preferably at higher concentrations normally take over the probabilistic/stochastic effects such as cancer and comprehensive dose-response models for such chemicals are very complex as compared to chemicals which are of non-carcinogenic nature. This is due to the reason that these chemicals obey both threshold as well as nonthreshold response models while causing overall damage in human cells and organs and related biological effects. In view of this, the judgment on the magnitude of threshold effects as well as risk per unit concentration may be further informative, especially for those chemicals for which the adverse effects have late manifestation. In the present article, the focus is mainly on Be-related biological effects and safety standards adopted for Be processing, manufacturing, handling, and associated philosophy behind setting various safety standards in more than the last 70 years and challenges ahead.
| Biological Effects Associated with Beryllium Exposure-Occupational Diseases | | |
Be is a lighter metal and belongs to the same chemical (divalent) group as Mg, Ca, etc., but unlike them, Be is highly toxic. Its chemical properties are similar to Aluminium (Al) as Be exhibits diagonal relationship with Al in the periodic table. As per the literature information, the diseases associated with Be inhalation are acute beryllium disease (ABD) and chronic beryllium disease (CBD). In cases of CBD, the lung is affected as small-small tissue nodules are formed on the inner side/lining of lung tissues causing problems in inflating of lungs, thereby leading to severe respiratory-related problems. It is important to mention that the information on the toxicity of Be on humans dates back to 1930s and the first report on the toxicity of Be was from Germany in 1933 which reported bronchitis and ABD in workers extracting Be from ore.[16] Similar reports on the toxic effects of Be on humans were from Italy in 1935 and from Russia in 1936.[16] During the end of the second world war, production and use of Be increased in the USA and cases of chemical pneumonia in workers extracting BeO from Be-based ores were reported by Van Ordstrand et al. in 1943.[3],[4]
Major information on the toxic effects of Be became available from (i) Fluorescent lamp manufacturing workers who were handling Be-based compounds such as Be Zinc Silicate (BeO4SiZn) and (ii) Workers extracting Be oxide from raw ore and those working in Be plants and (iii) Appearance of Be related diseases in personnel residing in the neighborhood of Be processing and manufacturing facilities. It was found that these workers were suffering from a disease like chemical pneumonia which was believed to be due to their occupation, i.e., Be-related works. Further details can be had from the seminal work of Van Ordstrand et al. published in the Cleveland Clinic Journal of Medicine.[3],[4] The typical symptoms associated with Be disease were “low-grade fever, shallow rapid respirations, mild-to-moderate cyanosis with fine crepitant rales throughout the lower half of both lungs”.[3],[4] It is considered that the workers suffering from Be-related diseases were exposed to high concentrations of Be and in such cases, the disease is termed as ABD which occurs when an occupational worker inhales high quantity/concentration of Be possibly >100 μg/m3 in a short durations or smaller period of time i.e., acute exposures. It is also worth to mention that skin-related diseases were also observed in workers or even in users of items containing Be i.e., resulted from cuts inflicted by a broken fluorescent lamp tube in which the phosphor was a compound of zinc Be silicate, manganese, and small amounts of finely divided and dispersed mercury even though the fluorescent industry had ceased production of the Be-containing phosphors but the use of these items continued even later.[3],[4]
Various exposure pathways from Be to humans exist and are via air and surface routes. Further worker's clothes, hands, and shoes can also contribute towards exposure from Be as it can become airborne leading to inhalation hazards. Further details about the same can be had from Day et al.[17] It is worth to mention that initially Be-related disease was thought to be mainly acute but later toxic effects were also observed in personnel exposed chronically, i.e., when occupational workers are exposed/inhale small-small concentration of Be day-by-day over longer periods, it is likely that few of them may develop CBD. It has been reported in the literature that those workers are more prone to CBD who are genetically allergic to Be i.e., popularly called as Be sensitization (BeS) which generally proceed the CBD.[1],[2],[18],[19],[20]
It is worth to mention that since 1950s, CBD is considered a major concern and with regard to this, Eisenbud had proposed that it is an immunological disease because- (i) CBD may occur at lower exposure concentrations, (ii) Be concentration in tissue does not correlate with severity of CBD and (iii) CBD may have latent period of many years after termination of Be work.[5],[6] It needs to be noted that CBD is incurable and irreversible and as of now no medical treatment exists for CBD.
It is also important to note that higher threshold dose/exposure values are associated for the prevalence of ABD and are unlikely to occur in normal working conditions in Be processing and machining facilities where proper safety, administrative, and engineering controls are ensured. However, under accidental or emergency exposure situations, in which it is likely that individuals possibly without proper respiratory protection if exposed to higher concentrations preferably >100 μg/m3, the prevalence of ABD is not ruled out. In addition, the chances of penetration of Be particles through pores of human skin are not ruled out and may cause skin-related diseases or other effects in human organs depending upon the degree of skin exposure.[17] Regarding the occurrence and development of CBD, scientific information is limited but it has been reported that CBD may occur in some of the occupational workers exposed to Be with indications that it may have very small dose threshold. Some of the reports indicate that BeS may be developed in ~16% of the exposed persons whereas CBD may occur in up to 11% of the exposed individuals especially working with Be machining or BeO handling and processing.[20],[21] Day et al. reported 7% prevalence of sensitization and 4% CBD in Be workers in a Be-based alloy facility whereas Schuler et al. reported 8.6% and 2.6% cases of BeS and CBD in Cu-Be alloy plant.[17],[22] As per Infante and Newman, the CBD prevalence ranged from (2% to 15%) depending on the Be-related jobs.[23] Few other reports show the prevalence of BeS and CBD up to ~20% and details can be had from the official statement of the American Thoracic Society.[24] Further details about reports on Be-related toxic effects, BeS, CBD, and associated issues can be had from various publications available in the literature.[25],[26],[27],[28],[29],[30],[31],[32]
Some reports indicate that toxicity of BeO is inversely proportional to firing or treatment temperature and air-borne particulates having lower size (<10 μm) may have substantial hazards associated. This is due to the effect that low-size BeO particles have more surface area (surface-to-volume ratio) and hence more chemical reactivity and such low-sized particles are generally associated with low firing or treatment temperature during the synthesis of BeO.[5],[6] Also, with regards to chronic adverse effects as well as CBD, there is no exact dose-response relation as the mechanism for CBD development in humans is not much understood.[33],[34] It may be speculated that CBD development in humans is similar to what can be described as deterministic unpredictability i.e., the effect may or may not occur albeit with or without any dose/exposure threshold. Based upon literature information, it can be seen that CBD may be characterized by- (i) Effect will occur in some exposed individuals possibly susceptible to BeS, (ii) Be exposure is not exact indicator of CBD as its role is not perfectly known (iii) Variable latent period (after many years) after exposure to Be for induction of CBD, etc.[1],[2],[5],[6],[35],[36],[37],[38],[39],[40] All this leads to the fact that CBD may occur in few % of individuals exposed to Be but there are many other factors describing and influencing induction of CBD indicating that it may be a type of effect characterized by deterministic unpredictability. Hence, it is logical to classify ABD purely as a deterministic effect as it occurs after a certain dose/exposure threshold but for CBD, it may not be logical to purely describe it as a biological effect with a known threshold i.e., pure deterministic effect. Hence, some components leading to CBD may have stochastic nature and it is logical to classify Be-induced CBD as a biological effect having deterministic unpredictability nature. However, as long as exposure or concentration limits for Be are based on the philosophy of effect characterized by the threshold model, it is to be considered that ABD as well as CBD, both are deterministic or threshold type of effects which exist in different concentration ranges to which humans may be exposed although it may not be logical to assume CBD as a deterministic effect alone.
Other than ABD and CBD, it has been reported that there may be dermatological effects of Be exposure i.e., skin reddening, burns or coloration, etc. Regarding genetic effects arising due to Be, there have been no conclusive evidence and it is considered that genetic effects are not associated with Be exposures. In addition, it is also reported that in the case of Be-contaminated skin, Be particles may penetrate the skin leading to skin reddening and in few cases, this exposure route can lead to BeS and later CBD.[27],[38] In fact, Be adverse effects may progress as BeS, sub-clinical CDB, and finally CBD. It is also worth to mention that no (conclusive) cases of CBD are reported to occur from natural exposure to Be from inhalation, ingestion, and skin deposition. Further details about Be-related effects on the human body can be had from the publications of the Scientific Committee on OEL (SCOEL), European Commission, Be Science and Technology Association (BeST), and other reports.[33],[34],[35],[36],[37],[38],[39],[40],[41]
| Basis of Safety Standards-Beryllium Air Concentration for Occupational Workers and Public/Environment | | |
In view of the chemical toxicity of Be resulting in chronic and acute diseases arising from inhalation of dust, fumes or particles of Be, the standard of 2.0 μg/m3 for Be in the air as particulate matter with time-weighted average over 8 h (limits on Be air concentration [BeAir-Conc]) was defined by Department of Energy (DOE), USA in 1948 and were adopted in the end of 1949.[5],[6] This was the first safety standard which put regulations on allowable BeAir-Conc or exposure and was initially termed as OEL at the time of its inception.[5],[6] Eisenbud who was part of the team during 1950s for setting the BeAir-Conc standard has brilliantly described the efforts and logic behind setting the Be standard for workplace and public environments.[5],[6]
The philosophy behind the adoption of 2.0 μg/m3 was based on the fact that during 1950s, ~100 μg/m3 in the air was an established value for occupational safety at workplaces as far as chemical toxicity of heavy metals (Pb, Hg, etc.) was concerned. For the sake of completeness, it especially needs to be mentioned that for heavy elements such as compounds of uranium, the present value of TLV as per ACGIH is 200 μg/m3 whereas the PEL value as per OSHA is 50 μg/m3[11] and is in accordance with the values adopted for other heavy elements such as Pb, Hg, As, and Cd and are given in [Table 1]b. It may be noted that earlier values of TLVs for these heavy elements were ~ (100-200) μg/m3 e.g., TLV for Pb was 150 μg/m3 in 1946.
Considering the fact that toxic heavy metals are of having an atomic weight of ~200 whereas 4Be9 is a light metal with an atomic weight of ~10 (ratio of the mass number of heavy metal to lighter metal = 200/10 = 20), assuming atom for atom toxicity, the typical value for Be exposure limit comes to be 5.0 μg/m3 (i.e., 100/20) as derived from heavy metals. In addition, an adjustment factor of 2.50 was further applied as the lung disease (CBD) associated with Be exposure is not only incurable but also irreversible and there was also no epidemiological data or details about its understanding during the 1940s. This finally lead to Be standard of (i.e., 5.0/2.5 = 2) 2.0 μg/m3 or 0.002 mg/m3 as a time-weighted average over 8 h or per shift (limits on BeAir-Conc) for occupational Be workers.[5],[6] In addition, the limit on peak value for occupational (BeAir-Conc) exposure as well as limits on allowed environmental (ambient/public) emissions or exposures as given in [Table 2] were also proposed and implemented by DOE in 1949.[5],[6] | Table 2: Be air concentration adopted/recommended in 1949 by department of energy, USA for occupational workers and members of public/ambient environmental air
Click here to view |
It needs to be mentioned that ambient/public air standards for Be [Table 2] were stringent compared with occupational workplace standards as public includes infants, children, women as well as those who may be suffering from severe medical health problems. In addition, the general public is likely to be exposed over 24 h/day rather than 8 h shift assumed for occupational workers i.e., weekly 40 h for occupational workers versus 168 h for members of the public.[6],[39] It has also been argued that there have been no cases of CBD among populations residing around Be plants for ambient air concentration ≤0.01 μg/m3 and it is also speculated that the minimum Be exposure which may lead to CBD is probably >0.01 μg/m3. In view of this, a value of 0.01 μg/m3 averaged over 30 days period was recommended as an environmental air limit in 1949. As per Eisenbud, the adoption of Be standard for public/community or ambient environment was the first standard to be adopted for the protection of the environment/public for control of environmental pollution.[6]
Further considering the possibility of instantaneous changes in BeAir-Conc and the requirement of flexibility in occupational areas, a maximum peak exposure limit of 25 μg/m3 over a 30-min period called as short-term exposure limit (STEL) value was also set. This STEL value of 25 μg/m3 adopted in 1949 was below the threshold of 100 μg/m3 believed to cause ABD and it was further ensured that daily time-weighted average TLV/PEL do not cross the recommended value of 2.0 μg/m3.
Above standards introduced in 1949 had no sound epidemiological and scientific basis except the availability of limited information on Be-based workers in the lamp (phosphor) industry and some other workers involved in BeO processing and manufacturing of Be metal and the recommendations were purely on limited toxicity information, judgment, and feasibility to achieve practically these values using the technology available those days for use in Be industry/facilities.
Interestingly, these standards recommended in late 1949 were of interim nature and were likely to be revoked and re-evaluated at the end of six months but were extended for 1 year. Further annual reviews continued for several years and after 8 years when it became evident that no new information is being added, the standards were finally adopted as such.[6] These standards were the stepping stone for Be safety and continued to be adopted for about last 70 years or so, since its inception. It is also worth to mention that during the 1940s and 1950s, the major concern was ABD, and setting TLV/PEL of 2.0 μg/m3/8 h shift (daily-weighted average) was much below the threshold concentration of 100 μg/m3 which was considered to cause ABD. This standard could eradicate the ABD prevalent then among the occupational workers handling Be in spite of the lack of sound epidemiological and scientific basis. As ABD was a matter of focus during the 1940s-1950s and was a major occupational hazard, whose prevalence among Be workers could be ruled out successfully at that time by adopting 2.0 μg/m3. Later, the standard of 2.0 μg/m3/8 h shift was adopted by ACGIH in 1959, AIHA in 1964, ANSI in 1970, OSHA in 1971, and NIOSH in 1972. Further details are given in [Table 3] which also includes values for Be exposure limit/level (BeAir-Conc) revised/proposed by above agencies including recent recommendations from European associations like SCOEL and BeST.[36],[38],[41],[42],[43],[44] | Table 3: Be air concentration for occupational workers recommended by various agencies/organizations over the last 70 years
Click here to view |
It also needs to be mentioned that in spite of the lack of sound epidemiological basis, the 1949 recommendations of DOE, USA were a balance amongst Be safety and its implementation in industry and related economical aspects. This may be a unique example where a safety recommendation (2.0 μg/m3/8 h shift) stayed for such a longer time period and that also almost worldwide although questions on the adequacy of 2.0 μg/m3 were raised in between and many times, various organizations recommended values lower than 2.0 μg/m3 but were not adopted practically.[36],[37],[39],[41],[42],[43],[44] It is further worth mentioning that the ambient air standard for the protection of the public from Be exposures having the value of 0.01 μg/m3 proposed in 1949 continues to be adopted till today and has been considered to be adequate to protect the public from Be associated hazards/diseases even in the neighborhood of Be facilities.
| Limits/Levels for Be Surface Concentration Inside Beryllium Plant and Equipment Release to Public Environment/Areas | | |
In addition to Be concentration in air, another issue of having relevance from Be safety is surface contamination by airborne Be particles, dust, etc., as well as of various systems and equipment being used in different operations inside Be facilities and allied areas. In addition, many times, equipment, items, and systems need to be moved out of the facility/area to public or normal areas. In view of this, limits for Be surface contamination were defined and are given in [Table 4] for Be facilities in the USA.[43],[44],[45],[46],[47],[48],[49] It may be noted that the surface contamination from Be-based compounds or materials may be volatile, wet, fixed, and removable and all scenarios must be taken into account. It must be noted that setting limits on Be surface contamination and thereafter control on Be contamination, not only rules out potential skin-related diseases and penetration of Be through skin pores, etc., but may also be helpful to limit the airborne concentration if Be particles or dust becomes airborne due to human activities of repair, disturbance, vibrations, and shaking of equipment/items. In view of this, the surface level limits are set in such a way that skin-related potential harms, and the spread of Be contamination is ruled out. Keeping surface contamination levels within limits, various human activities on contaminated walls, floors, objects, etc., may not lead to situations in which BeAir-Conc exceeds the recommended TLV/PEL value even if all Be particles or dust deposited on the surface becomes airborne or is re-suspended.
Similarly, for any equipment to be taken to public/ambient areas from plant or release of Be contaminated equipment to non-Be public areas, it is recommended that the surface of the equipment should be free from Be and must be decontaminated or properly cleaned. In view of this, 2 ng/cm2 (0.20 μg/100 cm2) surface contamination limit has been set in the USA.[43],[44],[45],[46],[47],[48],[49] It is expected that under no condition, the maximum air concentration for airborne Be concentration will exceed 0.01 μg/m3 even if all the Be dust deposited on equipment becomes airborne due to various disturbances for an item contaminated to a level of 2 ng/cm2.[46] It must be noted that re-suspension factors associated with lighter elements like Be range from ~ (10−5/cm to 10−8/cm) and it is unlikely that equipment exhibiting Be surface contamination level of ~2.0 ng/cm2 under various operations may lead to any adverse health effects.
It may be noted that the value of 1.0 ng/cm2 which was in use in DOE facilities in the USA was later replaced with 2.0 ng/cm2. As per Damian “the criterion of 2.0 ng/cm2 (0.2 μg/100 cm2) was designed to address equipment rather than building surfaces. Most importantly, this criterion is not based on health risks but rather on the excessive cost involved in washing and cleaning while performing decontamination of items for achieving the lower standard of 1 ng/cm2.[46] Futhermore, the implementation of the higher standard of 2.0 ng/cm2 would not result in any exceedance of the US Environmental Protection Agency's (EPA) national emission standards for hazardous air pollutants limit of 0.01 μg/m3 (public or environmental standard) and therefore, on that basis, 2.0 ng/cm2 would be a safe standard.”[46]
| Paradigm Shift-Recent Revision of Beryllium Air Concentration Standard From 2 μg/m3 TO 0.20 μg/m3 | | |
As mentioned earlier that the occupational air concentration (BeAir-Conc) limit of 2.0 μg/m3 as implemented in 1949 by DOE, USA, and later adopted by almost all countries having Be manufacturing facilities, etc., as well as Be-associated jobs. Although TLV for Be (BeAir-Conc) was analytically derived from the limits of toxic heavy metals but was lacking sound epidemiological data/basis. In view of this, there were continued efforts to further change the limit and many times such recommendations were proposed by various societies/bodies [Table 3]. Details about such recommendations are given in [Table 3] in which limits suggested by various bodies are given. However, in the absence of any solid reasoning behind the revised limits as well as the nonavailability of epidemiological data, none of the recommendations were implemented by the authorized agencies. It is also worth to mention that all the bodies agreed at one point of view that (BeAir-Conc) of 2.0 μg/m3 is successful and sufficient to eliminate ABD and there were no evidence/medical cases in which ABD was observed in occupational workers exposed to Be in various Be manufacturing and processing facilities worldwide. However, questions on the adequacy of BeAir-Conc. of 2.0 μg/m3 to eliminate CBD always remained and cases of CBD continued to be reported till recently. It is worth mentioning that as per Infante and Newman, even in plants complying with the 2.0 μg/m3 PEL, the CBD prevalence in occupational workers ranged from (2% to 15%) depending on the jobs in which workers were involved.[23] It is worth to mention that recommended exposure level (REL) of 0.50 μg/m3 as recommended by NIOSH in 1977 was intended to reduce the risk of lung cancer among Be workers and was not to prevent the occurrence of BeS and CBD.[50] NIOSH also recommended that plant authorities should keep airborne Be concentration as low as possible which was based on the logic that there may be no safe level of Be exposure.
In addition, in other studies performed by various researchers, it became evident that BeS and CBD were observed in workers for Be exposure values much less than 2.0 μg/m3.[20],[23],[51] Further, Schuler et al. reported that BeS and CBD were associated when Beair-conc levels exceeded 0.20 μg/m3 whereas Stanton et al. observed no BeS and CBD when 97% of Be exposure values in occupational workplaces were < 0.20 μg/m3.[52],[53] In this regard, the work of Madl et al. is important to mention and dealt with the issue of Be-induced sensitization (BeS), sub-clinical CBD, and CBD in detail.[54] From the epidemiological studies of Madl et al., it was revealed that “maintaining Be exposures < 0.20 μg/m3, 95% of the time may prevent BeS and CBD in workplace ” i.e., daily 8 h time-weighted average should not exceed 0.20 μg/m3.[54] It may also be noted that ACGIH in 2005 had also revised TLV to 0.05 μg/m3 [Table 3] for inhalable particles. In addition, as per information available from BeST, Proctor (2015) suggested NOAEL values of 0.065 μg/m3, 0.14 μg/m3, and 0.41 μg/m3 for respirable, total particulate, and inhalable fractions, respectively.[55] It may be noted that a conversion factor of 2.88 was suggested by Kock et al. for converting total particulate to inhalable fraction.[56] From this, it follows that the limit values suggested by ACGIH (2005) and Proctor (2015) for inhalable particles are 0.05 μg/m3 and 0.065 μg/m3 and are practically closer to each other.
All above mentioned studies along with the previously held notion that 2.0 μg/m3 was inadequate to protect occupational workers against BeS and CBD, led OSHA in 2017 to reduce the PEL value for Be in workplaces from 2.00 μg/m3 to 0.20 μg/m3 i.e., reduction by a factor of 10.[57],[58] In addition, 2.00 μg/m3 was also recommended as a revised STEL value averaged over 15 minutes against an earlier value of 25 μg/m3 averaged over 30 min adopted in 1949. It is expected that the revised PEL would be successful in eliminating the occurrence of BeS and CBD cases to further lowest levels. In view of the revision of PEL by OSHA, many countries have adopted the revised PEL whereas many others are in the process of adopting the revised PEL value or so.
| Indian Scenario on Beryllium Activities and Related Safety Standards –Present Status | | |
In India, Be-related ore mining activities date back to preindependence era and a survey of the literature shows that ~281 Ton beryl (3BeO A12O3 6SiO2) ore was mined in 1932 which raised to ~1500 Tons per year during the second world war although the whole of Beryl ore was exported.[59],[60] Post independence, because of strategic nature and associated applications of Be, the export of beryl ore was banned. From the literature, it can be seen that the attempts for extraction of Be from Beryl ore were made during the 1960s.[59],[60],[61],[62],[63] The work of Sankar Das and Athavale in 1955 who described “a rapid volumetric method for the determination of Beryllium in Beryls and associated minerals” is worth mentioning.[61] In addition, in the proceedings of the symposium on pilot plants in metallurgical research and development held at the National Metallurgy Laboratory, Jamshedpur in 1960, Srinivasan and Tendolkar describe the pilot plant to be established by the Department of Atomic Energy (DAE) for production of sintered Be oxide from beryl ore.[63]
Regarding Be protection-related standards in India, a survey of the literature shows that in DAE the safety-related guidelines were framed way back in 1960 by Soman and Kamath.[64] Furthermore, the information on studies regarding analytical determination of Be can be found from the publication of Desai and Sudhalatha which mention co-precipitation of microgram of Be with organic reagents and estimation of μg level of Be in urine using fluorometry-based technique.[65] Another study which needs to be mentioned is that of Bhat et al., 1965 which describes a method for estimation of Be using gravimetric technique.[66] Further details about Beryllium related works and associated studies can be had from Subbarao et al, 1977,[67] Sundram et al., 1985,[68] Saha and Mistry, 1992,[69] Sharma, 1993,[70] various publications in “Mineral Processing and Extractive Metallurgy Review: An International Journal” in 1994,[71],[72] Sharma et al., 1999,[73] Rath et al., 2013,[74] and that of Sharma and Sinha, 1995,[75] Thorat et al., 2011,[76] Tripathi et al., 2013,[77] Nair et al., 2014,[78] Mohanty et al., 2014,[79] Tripathi et al., 2015[80] and Sinha, 2016[81] and Nair et al., 2019.[82] One of the most recent article which provides a summary about Be-related activities and the establishment of pilot scale facility in BARC to meet the demands of Be in different sectors is that of Kain et al.[83] In this regard, further comprehensive details about “Extraction and Powder Metallurgy of Beryllium” can be had from the book – “Atomic Energy in India-50 Years” by Sundram, Krishnan, and Iyengar published by the Department of Atomic Energy in 1998.[84] These articles report Be-related ores, processes, extraction, machining activities as well as a summary of Be-related safety by some of the authors but are beyond the scope of this article.
As per the Atomic Energy Act, 1962 of the Government of India, Be is categorized as a prescribed substance.[83],[84],[85],[86] Details about the Be safety procedures, operations, and protocols can be had from Atomic Energy Factory Rules, 1996.[85],[86],[87] In DAE, the term permissible limit of exposure (PLE) numerically the same as PEL or TLV) is generally popular for BeAir-Conc. However, outside DAE, the Directorate General Factory Advice and Labor Institutes (DGFASLI) of the Ministry of Labor and Employment, India recommends the permissible levels/limits of exposure of chemical substances including Be in the work environment as mentioned in the factories act, 1948.[88] Historical details about various regulatory limits pertaining to Be (BeAir-Conc) as available from literature survey for occupational workers and ambient air standards for the public as adopted in India are given in [Table 5].[63],[64],[67],[68],[69],[70],[85],[86],[87],[88],[89],[90],[91],[92],[93],[94],[95],[96],[97],[98],[99],[100],[101],[102],[103],[104],[105],[106],[107],[108] For the sake of completeness, information on surface contamination levels as available from the literature survey for the workplace and any equipment to be taken to public/ambient areas from Be facility/areas is also given. It is worth mentioning that presently the PLE value of 0.20 μg/m3 with STEL of 2.0 μg/m3 is followed from 2021 and this change in PLE value in DAE is in line with the revisions adopted by OSHA.[57],[58] | Table 5: Be air concentration, surface level contamination, and effluent discharge criteria's as adopted in India[63],[64],[67],[68],[69],[70],[85],[86],[87],[88],[89],[90],[91],[92],[93],[94],[95],[96],[97],[98],[99],[100],[101],[102],[103],[104],[105],[106],[107],[108]
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Detailed information about air concentration and surface level contamination limits followed in India from 1960s to 2021 is given in [Table 5]. It can be seen from the values that Be surface contamination levels for the workplace as well as equipment clearance are lower when compared with the levels/limits practiced in the USA which are also given in [Table 2]. Further details about the values of various Be safety standards i.e., BeAir-Conc and surface contamination levels and Be-based effluent discharges as adopted in India and other safety-related information can be had from the publications of various Indian authors.[89],[90],[91],[92],[93],[94],[95],[96],[97],[98],[99],[100],[101],[102],[103],[104],[105]
| World-Wide Status on Beryllium TLV or PEL Standards-Present Scenario | | |
Looking at the recent changes in PEL for Be shows that many countries have already adopted the revised PEL of 0.20 μg/m3 whereas other countries are planning in a phased manner and further details are given in [Table 6].[109],[110],[111],[112],[113],[114] From [Table 6], it can be seen that in some countries such as Australia, the United Kingdom, Singapore, and South Korea still the TLV/PEL value of 2.0 μg/m3 is being continued whereas in other countries such as Denmark and Kazakhstan, the TLV/PEL value of 1.0 μg/m3 is followed. In China, the TLV/PEL of 0.50 μg/m3 is followed. Some of the countries such as the USA, Ireland, Israel, Poland, and Spain, the TLV/PEL value of 0.20 μg/m3 is followed whereas in Finland TLV/PEL of 0.10 μg/m3 is in practice. Some of the countries such as Belgium have adopted further much lower value of TLV/PEL which is 0.05 μg/m3 whereas in Germany, the TLV/PEL of 0.06 μg/m3 and 0.14 μg/m3 are adopted for respirable and inhalable particles, respectively. Further in Sweden, the TLV/PEL of 0.60 μg/m3 is followed for inhalable fraction and is valid until July 10, 2026, after which TLV/PEL of 0.20 μg/m3 will be adopted and is in line with the decision of the European Union. It is also worth to mention that in Canada as well as Japan, two different TLV/PEL are adopted i.e., in Canada, the TLV/PEL of 0.15 μg/m3 and 2.00 μg/m3 are followed in Ontario and Quebec, respectively, whereas in Japan, MHLW and JOSH follow TLV/PEL of 1.00 μg/m3 and 2.00 μg/m3, respectively. It must be noted that in European Union (EU), the present TLV/PEL is 0.60 μg/m3 and the PEL of 0.20 μg/m3 will be adopted in July 2026. | Table 6: Present status about be exposure limits in various countries[109],[110],[111],[112],[113],[114]
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It also needs to be noted that based on BeS in occupational workers, the TLV/PEL of 0.02 μg/m3 [Table 3] has been recommended by the SCOEL whereas another European Association i.e., BeST has recommended a TLV/PEL value of 0.20 μg/m3.[37],[41] Further the reports suggest that BeST doesn't agree with TLV/PEL of 0.02 μg/m3 as recommended by SCOEL as it is not technically and economically feasible. In fact, BeST states that TLV must be based on the critical health outcome which is CBD and not BeS.
Further, it can be shown from [Table 6] that worldwide, there are differences in the values of STEL which ranges from (0.40 to10) μg/m3 although in many countries there are no criteria for adopting STEL level/limit value. It may be noted that the TLV of 0.20 μg/m3 (2.00 μg/m3 previously) for BeAir-Conc is for total particulate (<30 μm) however, in Germany and Sweden, also mentioned in [Table 6], the TLV for respirable or inhalable fraction are adopted separately. It may be noted that inhalable fractions may have particle sizes up to 100 μm whereas respirable fractions generally have particle sizes <10 μm. As described previously, the conversion factor of 2.88 for converting total particulate to inhalable fraction can be used.[56]
| Challenges Ahead | | |
In view of the revised PEL value by OSHA in 2017 for BeAir-Conc of 0.20 μg/m3 applicable for occupational workers i.e., reduction in PEL value by a factor of 10 or recommendation of TLV of 0.05 μg/m3 by ACGIH in 2005, it is a challenge to maintain such low values in Be facilities unless proper administrative and other control measures like process related engineering along with improvements in ventilation systems are implemented. In addition to primary and secondary enclosures for handling Be, especially in powder form or related extractive metallurgical processes, local ventilation or exhaust may be further required in Be facilities in order to maintain such low values as recommended by OSHA or ACGIH. Further, it is also worth mentioning that huge monetary costs are additionally required to implement such engineering control measures. In view of this, it will not be advisable to further lower TLV values to 0.05 μg/m3 as recommended by ACGIH in 2005 as the same will be not only uneconomical but impractical also and is an engineering challenge as well. Further, the recommendation of SCOEL for Be air concentrating in occupational workplaces for having a value of 0.02 μg/m3 is impossible to achieve within present designs of Be facilities worldwide unless glove boxes for handling Be along with efficient ventilation and related dust suction-based equipment are to be used. However, all these recommendations regarding the further lowering of PEL/TLV to much lower levels indicate the high toxicity and hazards associated with Be handling especially for chronic effects such as CBD.
In addition, regarding Be-related diseases in humans, it is worth mentioning that setting TLV of 2.0 μg/m3 in 1949 have eradicated ABD and ABD is unlikely to be observed except at higher TLV values which might be encountered in an emergency or accidental exposure conditions only. However, CBD is not fully eradicated as there are evidence of its occurrences in workers exposed to much lower concentration although may be after longer delayed periods. Although CBD is considered as a threshold effect, long-delayed periods and occurrence at lower exposure values and absence of exposure-response relationship indicate that it may be a stochastic effect to some extent as well although the BeS of individuals may also have role.
| Conclusions | | |
The present article provides details about the evolution of Be safety standards over the last 70 years, the notion behind the recent revision of PEL value for Be from 2.0 μg/m3 to 0.20 μg/m3 by OSHA and associated safety challenges ahead. The information from literature about Be safety and related standards adopted in India is also given. In addition, the paper attempts to correlate chronic, acute and other diseases (like cancer) with deterministic and stochastic nature of these effects arising out of Be exposures. The article also provide details about TLVs for BeAir-Conc being followed in various countries in the world and various challenges for the implementation of a revised PEL value of 0.20 μg/m3 as suggested by OSHA i.e., reduction in PEL value by a factor of 10 or recommendation of revised TLV of 0.05 μg/m3 by ACGIH as compared to the previous value of 2.0 μg/m3. In addition, information about different notations being used by various agencies and their recommendations regarding Be TLV, PEL etc., are included. Be safety is an important issue for the safety of individual's at occupational workplaces as well as of the environment and in the absence of collated and updated information, its compilation was highly needed for providing comprehensive information. In addition, in the absence of any online Be detectors which could be implemented practically similar to those used in radiological fields and the absence of an exact exposure-response relationship, Be safety is likely to be a challenging job worldwide in the future as well.
Acknowledgements
The authors are grateful to Dr. D. K. Aswal, Director, Health Safety and Environmental Group, BARC for his encouragement and support in carrying out the work.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
| 1. | Taylor JS, Dweik RA, Taylor JM. Metal allergy: Beryllium. In: Metal Allergy. Cham: Springer International Publishing; 2018. p. 337-47.  |
| 2. | Jakubowski M, PałczyŃski C. Beryllium. In: Handbook on the Toxicology of Metals. Academic Press; 2015. p. 635-53. |
| 3. | Van Ordstrand HS, Hughes R, Carmody MG. Chemical pneumonia in workers extracting beryllium oxide. Cleve Clin J Med 1943;10:10-8. |
| 4. | Van Ordstrand HS, Netherton EW. Beryllium skin granulomas from a broken fluorescent tube; report of a case. Cleve Clin Q 1950;17:34-7. |
| 5. | Eisenbud M. Origins of the standards for control of beryllium disease (1947-1949). Environ Res 1982;27:79-88. |
| 6. | Eisenbud M. The standard for control of chronic beryllium disease. Appl Occup Environ Hyg 1998;13:25-31. |
| 7. | American Conference of Governmental Industrial Hygienists: Beryllium: Effect on Worker Health. ACGIH Conference. In Hilton Crystal City Hotel at National Airport, Washington, D.C.; 1999. |
| 8. | American Conference of Governmental Industrial Hygienists (ACGIH). Documentation of the TLVs and BEIs with Other Worldwide Occupational Exposure Values; 2008. |
| 9. | National Institute for Occupational Safety and Health. Industry-Wide Study of Beryllium Production Facilities. Cincinnati: NIOSH; 1973. |
| 10. | EPA ORD NCEA Integrated Risk Information System U. Toxicological Review of Beryllium and Compounds (CAS No.7440-41-7); U.S. Environmental Protection Agency Washington, EPA/635/R-98/008 1998. p. 1-87. |
| 11. | Stradling N, Hodgson A, Ansoborlo E, Bérard P, Etherington G, Fell T, et al. Optimising monitoring regimens for inhaled uranium oxides. Radiat Prot Dosimetry 2003;105:109-14. |
| 12. | Asante-Duah K. Criteria used in establishing guideline values. In: Public Health Risk Assessment for Human Exposure to Chemicals. Vol. 27, Ch. 2. Dordrecht: Springer Netherlands; 2017, p. 1-600. |
| 13. | Air Quality Guidelines for Europe (WHO Regional Publications, European Series, No. 91), Criteria used in establishing guideline values, 2 nd ed., Ch. 2. Copenhagen, Denmark: WHO Regional Office: 2000. p. 11-31. |
| 14. | Phyper J, Ducas P, Baish PJ. Global Materials Compliance Handbook. Hoboken, NJ, USA: John Wiley & Sons, Inc.; 2004. p. 441-57. |
| 15. | Whaley DA, Attfield MD, Bedillion EJ, Walter KM, Yi Q. Regression method to estimate provisional TLV/WEEL-equivalents for non-carcinogens. Ann Occup Hyg 2000;44:361-74. |
| 16. | Sneddon IB. Beryllium disease. Postgrad Med J 1958;34:262-7. |
| 17. | Day GA, Dufresne A, Stefaniak AB, Schuler CR, Stanton ML, Miller WE, et al. Exposure pathway assessment at a copper-beryllium alloy facility. Ann Occup Hyg 2007;51:67-80. |
| 18. | Taylor TP, Ding M, Ehler DS, Foreman TM, Kaszuba JP, Sauer NN. Beryllium in the environment: A review. J Environ Sci Health A Tox Hazard Subst Environ Eng 2003;38:439-69. |
| 19. | Stange AW, Hilmas DE, Furman FJ, Gatliffe TR. Beryllium sensitization and chronic beryllium disease at a former nuclear weapons facility. Appl Occup Environ Hyg 2001;16:405-17. |
| 20. | Seidler A, Euler U, Müller-Quernheim J, Gaede KI, Latza U, Groneberg D, et al. Systematic review: Progression of beryllium sensitization to chronic beryllium disease. Occup Med (Lond) 2012;62:506-13. |
| 21. | Frye BC, Quartucci C, Rakete S, Grubanovic A, Höhne K, Mangold F, et al. A cluster of beryllium sensitization traced to the presence of beryllium in concrete dust. Chest 2021;159:1084-93. |
| 22. | Schuler CR, Kitt MM, Henneberger PK, Deubner DC, Kreiss K. Cumulative sensitization and disease in a beryllium oxide ceramics worker cohort. J Occup Environ Med 2008;50:1343-50. |
| 23. | Infante PF, Newman LS. Beryllium exposure and chronic beryllium disease. Lancet 2004;363:415-6. |
| 24. | Balmes JR, Abraham JL, Dweik RA, Fireman E, Fontenot AP, Maier LA, et al. An official American Thoracic Society statement: Diagnosis and management of beryllium sensitivity and chronic beryllium disease. Am J Respir Crit Care Med 2014;190:e34-59. |
| 25. | WHO. Beryllium and Beryllium Compounds. Geneva: WHO; 2001. p. 1-73. |
| 26. | Workplace Exposure Limits, UK, Containing the List of Workplace Exposure Limits for Use with the Control of Substances Hazardous to Health Regulations 2002 (as amended), EH40/2005. 4 th ed.; 2020. |
| 27. | Day GA, Stefaniak AB, Weston A, Tinkle SS. Beryllium exposure: Dermal and immunological considerations. Int Arch Occup Environ Health 2006;79:161-4. |
| 28. | Cooper RG, Harrison AP. The uses and adverse effects of beryllium on health. Indian J Occup Environ Med 2009;13:65-76. [ PUBMED] [Full text] |
| 29. | Darby A, Fishwick D. A Review of the Health Effects and the Evidence for Screening or Surveillance in Workers Exposed to Beryllium, Health and Safety Laboratory for the Health and Safety Executive; 2011. p. 1-29. |
| 30. | Rosenman K, Hertzberg V, Rice C, Reilly MJ, Aronchick J, Parker JE, et al. Chronic beryllium disease and sensitization at a beryllium processing facility. Environ Health Perspect 2005;113:1366-72. |
| 31. | Health Assessment Document for Beryllium, U.S. Environmental Protection Agency, Washington. EPA/600/8-84/026F 1987. p. 1-20. |
| 32. | A Review of the Toxicity of Beryllium in Air, Science Report – SC020104/SR1. UK; 2008. |
| 33. | Virji MA, Schuler CR, Cox-Ganser J, Stanton ML, Kent MS, Kreiss K, et al. Associations of metrics of peak inhalation exposure and skin exposure indices with beryllium sensitization at a beryllium manufacturing facility. Ann Work Expo Health 2019;63:856-69. |
| 34. | Tinkle SS, Antonini JM, Rich BA, Roberts JR, Salmen R, DePree K, et al. Skin as a route of exposure and sensitization in chronic beryllium disease. Environ Health Perspect 2003;111:1202-8. |
| 35. | MacMurdo MG, Mroz MM, Culver DA, Dweik RA, Maier LA. Chronic beryllium disease: Update on a moving target. Chest 2020;158:2458-66. |
| 36. | Hartwig A, Heederik D, Bellevaux de Nemery B, Nielsem GD, Loveren Van H Papameleetiou D, Klein CL. Beryllium and Inorganic Compounds, Recommendation from the Scientific Committee on Occupational Exposure Limits -SCOEL/REC/175; 2017. p. 1-53. |
| 37. | Garrett S, Meg P, Kalberlah F, Oltmanns J, Vencovsku D. Beryllium and Its Inorganic Compounds – Final Report on Beryllium, European Commission, 2018; 2018. |
| 38. | Kreiss K, Wasserman S, Mroz MM, Newman LS. Beryllium disease screening in the ceramics industry. Blood lymphocyte test performance and exposure-disease relations. J Occup Med 1993;35:267-74. |
| 39. | Managing Health Effects of Beryllium Exposure, Committee on Beryllium Alloy Exposures, Committee on Toxicology. Board on Environmental Studies and Toxicology Division on Earth and Life Studies, National Research Council of the Research Academies, The National Academic Press, Washington. 2008. p. 1-138. |
| 40. | Environmental Heath Criteria 106, Beryllium. (EHC 106, 1990) International Programme on Chemical Safety, WHO Geneva, 1990. p. 1-136. |
| 41. | |
| 42. | Kolanz ME, Madl AK, Kelsh MA, Kent MS, Kalmes RM, Paustenbach DJ. A comparison and critique of historical and current exposure assessment methods for beryllium: Implications for evaluating risk of chronic beryllium disease. Appl Occup Environ Hyg 2001;16:593-614. |
| 43. | Borak J. The beryllium occupational exposure limit: Historical origin and current inadequacy. J Occup Environ Med 2006;48:109-16. |
| 44. | Wambach PF, Laul JC. Beryllium health effects, exposure limits and regulatory requirements. J Chem Health Saf 2008;15:5-12. |
| 45. | Adams L, Agrawal A, Cronin JP, Ashley K. Optical molecular fluorescence determination of ultra-trace beryllium in occupational and environmental samples using highly alkaline conditions. Int J Environ Anal Chem 2017;97:264-75. |
| 46. | Damian P. Development of a health risk-based surface contamination cleanup standard for occupational exposure to beryllium. Toxicol Mech Methods 2011;21:97-102. |
| 47. | Ashley K, Braybrooke G, Jahn SD, Brisson MJ, White KT. Analytical Performance Criteria. Standardized surface dust sampling methods for metals, with emphasis on beryllium. J Occup Environ Hyg 2009;6:D97-100. |
| 48. | Creek KL, Whitney G, Ashley K. Vacuum sampling techniques for industrial hygienists, with emphasis on beryllium dust sampling. J Environ Monit 2006;8:612-8. |
| 49. | |
| 50. | |
| 51. | Arjomandi M, Seward J, Gotway MB, Nishimura S, Fulton GP, Thundiyil J, et al. Low prevalence of chronic beryllium disease among workers at a nuclear weapons research and development facility. J Occup Environ Med 2010;52:647-52. |
| 52. | Stanton ML, Henneberger PK, Kent MS, Deubner DC, Kreiss K, Schuler CR. Sensitization and chronic beryllium disease among workers in copper-beryllium distribution centers. J Occup Environ Med 2006;48:204-11. |
| 53. | Schuler CR, Virji MA, Deubner DC, Stanton ML, Stefaniak AB, Day GA, et al. Sensitization and chronic beryllium disease at a primary manufacturing facility, part 3: Exposure-response among short-term workers. Scand J Work Environ Health 2012;38:270-81. |
| 54. | Madl AK, Unice K, Brown JL, Kolanz ME, Kent MS. Exposure-response analysis for beryllium sensitization and chronic beryllium disease among workers in a beryllium metal machining plant. J Occup Environ Hyg 2007;4:448-66. |
| 55. | |
| 56. | Kock H, Civic T, Koch W. Beryllium concentrations at European workplaces: Comparison of 'total' and inhalable particulate measurements. Ann Occup Hyg 2015;59:788-96. |
| 57. | |
| 58. | Phillips JA. Beryllium standard update. Workplace Health Saf 2019;67:264. |
| 59. | |
| 60. | Chakravarti PB. Production of beryllium oxide from beryl. J Sci Ind Res (India) 1954;13:783-7. |
| 61. | Sankar Das M, Athavale VT. A rapid volumetric method for the determination of Beryllium in Beryls and associated minerals. Anal Chem Acta 1955;12:6-12. |
| 62. | Asundi MK. The role of light metals in nuclear engineering. Jamshedpur: NML; 1960. p. 171-8. |
| 63. | Srinivasan N, Tendolkar GS. Proposed pilot plant for production of sintered Beryllium oxide from beryl ore. Proceedings of the Symposium on Pilot Plants in Metallurgical Research and Development. 1960;15;1-6. Available from: https://eprints.nmlindia.org/3959/. [Last accessed on 2023 Apr, 18]. |
| 64. | Soman SD, Kamath PR. Toxicity and handling hazards of Beryllium, Atomic Energy Establishment Trombay (AEET) 1960. Report No. AEET/HP/SM/7. |
| 65. | Desai SR, Sudhalatha KK. Determination of mu-amounts of beryllium in urine. Talanta 1967;14:1346-9. |
| 66. | Bhat A, Gupta R, Jain B. BIS-2-pyridyl glycol as a reagent for gravimetric determination of uranium, aluminium and beryllium. Indian Acad Sci Proc A 1966;63:356-60. |
| 67. | Subbarao KS, Sharma BP, Paul CM, Sundaram CV. Beryllium Development Program in India, 4 th International Conference on Beryllium, London; 1977. |
| 68. | Sundaram CV, Paul CM, Sharma BP, Nair JS, Saha S. Pilot plant production of beryllium metal and copper-beryllium alloys. Key Eng Mater 1985;8:251-71. |
| 69. | Saha S, Mistry BP. Beryllium – Its use in India and hazard control. Ind Prod Finder 1992;21:263-4. |
| 70. | Sharma BP. Beryllium facilities in India. High Temp Mater Proc 1993;11:294-304. |
| 71. | Gupta CK. A few minutes with beryllium. Miner Proc Extra Metall Rev 1994;13:1-11. |
| 72. | Saha S, Ghanwat SJ. Chemical milling of beryllium. Ind Prod Finder 1994;22:255-7. |
| 73. | Sharma BP, Sinha PK, Mahata T, Narasimhan S, Shyambabu M, Mawal NE. Powder Metallurgy Equipment for Processing of Special Materials, Proceedings of “PM Industry Equipment and Plant Practice, PM-99”, New-Delhi; 1999. |
| 74. | Rath BN, Ghanwat SJ, Kaity S, Chandan D, Kulkarni RV, Alur VD , et al. Thermal conductivity of composites of beryllia and lithium titanate. J Mater Eng Perform 2013;22:3455-60. |
| 75. | Sharma BP, Sinha PK, Offshoots from Be Development Programme, Conference on Metallurgy in Western India: Golden Years ahead (GOLDMET-95), Bombay; 1995. |
| 76. | Thorat DD, Tripathi BM, Sathiyamoorthy D. Extraction of beryllium from Indian beryl by ammonium hydrofluride. Hydrometallurgy 2011;109:18-22. |
| 77. | Tripathi BM, Prakash J, Thorat DD, Sathiyamoorthy D. Statistical evaluation of ammonium hydrofluride process for beryllium extraction from Indian beryl ore. J Powder Metall Min 2013;2:118. |
| 78. | Nair Sathi R, Ghanwat GJ, Patro PK, Shyambabu M, Mawal NE, Mahata T, et al. Evaluation of Thermal Properties of Sintered Beryllium Oxide Produced from Indian Beryl Ore, Proceedings of the DAE-BRNS Fifth Interdisciplinary Symposium on Materials Chemistry, Mumbai; 2014. p. 115. |
| 79. | Mohanty T, Tripathi BM, Mahata T, Sinha PK. Arc Plasama Assisted Rotating Electrode Process for Preparation of Metal Pebbles, Proceedings of the Twenty Sixth International Symposiums on Discharges and Electrical Insulation in Vacuum (ISDEIV-2014), Mumbai; 2014. p. 741-4. |
| 80. | Tripathi BM, Prakash D, Sinha PK. Physico-chemical characterization of red mud produced during extraction of beryllium. Trans Powder Metall Assoc 2015;41:9-12. |
| 81. | Sinha PK. High Temperature Conductivity BeO and Silicon Ceramics: Processing Properties and Applications, Proceedings National Workshop towards Self Reliance in Advanced Ceramics (ACer-2016); 2016. p. 7. |
| 82. | Nair SR, Sinha A, Patro PK, Lenka RK, Sinha PK. Synthesis of High Purity Beryllium Oxide from Beryllium Hydroxide by Carbonate Route for Reactor Applications, Proceedings of Conference on Indigenous Fuel Programme in India-Achievements, Status, and Prospectus, Mumbai; 2019. p. 42-3. |
| 83. | Kain V, Sinha DK, Singh D, Asnani CK. Atomic minerals: Journey of India to self-sufficiency. Curr Sci 2022;123:293-309. |
| 84. | |
| 85. | |
| 86. | |
| 87. | |
| 88. | |
| 89. | Narayan S, Ramamurthy A. Health and safety aspects of beryllium operations. Miner Process Extra Metall Rev 1995;14:301-18. |
| 90. | Saha S, Roy PR. Assessment of waste of a beryllium extraction plant. Waste Manag 1992;12:17-21. |
| 91. | Thorat DD. Studies on Analytical and Environmental Characterization of Beryllium, PhD Thesis University of Mumbai; 1997. |
| 92. | Bhat PN, Pillai KC. Leachability and immobilisation of beryllium from solid waste (red-mud) generated in processing beryl. Water Air Soil Pollut 1997;94:297-306. |
| 93. | Ramamurthy A, Vedak SB, Aga AJ, Somayaji KS. Evaluation and control of Beryllium hazards in research and development operations. Indian J Occupational Health 1972;15:13-9. |
| 94. | Thorat DD, Mahadevan TN, Ghosh DK, Narayan S. Beryllium concentrations in ambient air and its source identification. A case study. Environ Monit Assess 2001;69:49-61. |
| 95. | |
| 96. | Thorat DD, Mahadevan TN, Ghosh DK. Particle size distribution and respiratory deposition estimates of beryllium aerosols in an extraction and processing plant. AIHA J (Fairfax, Va) 2003;64:522-7. |
| 97. | Sathiyamoorthy D, Mohanty T, Srinivas K, Selvaraj D, Thorat DD. Beryllium pebbles preparation and modeling of rotating electrode process. Fusion Sci Technol 2012;61:159-66. |
| 98. | Bhat PN, Soundararajan S, Sharma DN. Study on seasonal variation of metal ion (Beryllium) concentration in water, sediment and its distribution in a stream. J Inst Eng India Ser A 2015;96:151-60. |
| 99. | Bhat PN, Vajarekar AS. Beryllium Safety: Challenges and Solutions, 36 th DAE Safety and Occupational Health Professionals Meet to be Held at NFC. In Hyderabad; 2019. p. 86-8. |
| 100. | Kumar M, Kamble MK, Srivastava A. Emergency Preparedness during Beryllium Handling, Operations & Associated Challenges, 37 th DAE Safety & Occupational Health Professionals Meet, 8 th-9 th October, 2021. Vol. 37; 2021. p. 1-2. |
| 101. | Kumar M, Kamble MK, Srivastava A. Studies on Fluorescence Response with Be Concentration and Its Estimation. Vol. 2. Proceedings of DAE Second Symposium on Current Trends in Analytical Chemistry (CTAC-2021); 2021. p. 58. |
| 102. | Kamble MK, Kumar M, Prasad S, Srivastava A. Safety Management during COVID-19 Pandemic: Experiences from Beryllium Safety Hygiene Practices, 37 th DAE Safety & Occupational Health Professionals Meet, 8 th-9 th October 2021. Vol. 37; 2021. p. 1-2. |
| 103. | Kumar M, Srivastava A. Risks associated with beryllium exposure, comparison with radiological risk philosophy and response models. Radiat Protect Environ 2023;46:S2-3. |
| 104. | Chauhan A, Kumar M, Kamble MK, Srivastava A. An update on beryllium ambient air concentration in Navi-Mumbai, India – 30 years status. Radiat Protect Environ 2023;46:S399-400. |
| 105. | Kamble MK, Kumar M, Chauhan A, Srivastava A. Industrial hygiene surveillance practices for beryllium workplaces and role of re-suspension factor. Radiat Protect Environ 2023;46:S451-2. |
| 106. | The Hazardous and Other Wastes (Management and Transboundary Movement) Rules, 2016, Pollution Control Acts, Rules & Notifications Issued there under, 2021. CPCB; 2021. |
| 107. | Paul CM, Sharma BP, Sobbarao KS, Rajadhyaksha MG, Sundaram CV. Preparation of Copper-Beryllium Alloys from Indian Beryl, BARC-794; 1975. |
| 108. | Sarathi IV, Mahadevan TN, Krishnamoorthy TN. Leaching Characteristics of Beryllium in Red Mud Waste and Its Stabilization in Cement, BARC Report No. 035 (External); 1998. p. 1-48. |
| 109. | International Limit Values, Maintained by the Institut für Arbeitsschutz der Deutschen Gesetzlichen Unfallversicherung (IFA, Institute for Occupational Safety and Health of the German Social Accident Insurance). Available from: https://limitvalue.ifa.dguv.de/WebForm_ueliste2.aspxGESTIS. [Last accessed on 2023 Apr, 09]. |
| 110. | |
| 111. | |
| 112. | Johnson JS, Foote K, McClean M, Cogbill G. Beryllium exposure control program at the Cardiff atomic weapons establishment in the United Kingdom. Appl Occup Environ Hyg 2001;16:619-30. |
| 113. | Vincent R, Catani J, Créau Y, Frocaut AM, Good A, Goutet P, et al. Occupational exposure to beryllium in French enterprises: A survey of airborne exposure and surface levels. Ann Occup Hyg 2009;53:363-72. |
| 114. | Brisson MJ, Ashley K. Sampling and analysis issues relating to the ACGIH notice of intended change for the beryllium threshold limit value. J Occup Environ Hyg 2005;2:D97-9. |
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]
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