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Philip Morris

Occupational Toxicology Chapter 17

Date: 19940000/P
Length: 22 pages
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Page, N.P.
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MARG, MARGINALIA
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2063794653/4953

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Basic Environmental Toxicology
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' ' _ ~- ,/38a y .~ ". j CuSTWrt ER COPg tUw Ises Copy Comp ment Deliueri CAS Do 1800-6i8-4337 hpptei ~\Occupational Toxicology Norbert P, Page , i ' , , ' , ' , ' ' A. INTRODUCTION Early in the 20th century, with the introduction of the automobile, an expanding petrochemical industry, and production liaemetnods, the workplace envirantttent changed from one of mainly small, isolated shope to one domi- nated by large factories employing many workers. In many wses, workers were crowded into buildings with poorventiladon and minimal safety conttols, and the hazards of chemicals became moee evident• Petroleum and mined materiais, e.g., asbestos and metals, could now be removed from the earth, transported great distances, and huroduced into a plethora of manufactured products. ihe natuc of thetvorkplace today is quite varied, from workers on large producoon lines in manufacturing plants to workers in small groups or individuals working alone such as in the application of pesticides. Regardless of the nanue of employment, worJcers in virtually aIl places ate potentially exposed to chemicals. In fact, the Occupational Safety and Health Adnunistra- tion (OSHA) estimated in 1987 that 32 millioo worYes were potentially exposed to chemical hazards (OSHA, 19g7). . As the industrial and chemical revolution progressed, knowledge of the hannful effects of chemicals primarily eesuitedfivm exposures occurring in the workplace and the effects that were observed in_ worker populations.It was not until the 1930s and 1940s, that safetytesdng with laboratory animals began, and.only then by some of the larger companies to assess toxicity for high volume chemicals. Tbe concerns were for immediate acute effects such as death or skin and eye damage with little regard for long term effects or the potential for birth defects. Competing corporations ardently protected their etpYYn-IyYIDLMLe I9Y1y'OtCIw•Ic 457 ; . drrk~'ea N # ~ co CN 1, ~r_.. ~, s;; .~ 00 0 0 ., ~~. e~as s'~•.1
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08 Basic Snvironmental Taricolvgy W7:.:'t. data with minimal exchange and publication of the health dffects data. (To some extent this problem still exists today, although government regulations now require that adverse health effects data be made available to the public.) B. GOVERNMENT REGULATIONS FOR INDUSTRIAL CHEMICALS Before the establishment of the American Conference of Governrnenml Industrial Hygienists (ACGIH) in 1938, there was no meaningful govenamen- tal strveillance, so the protection of workers was haphazard. Smx that time numerous laws (federal, state, and local governments) have been implemented that require the careful adherence by industrial hygienists and occupational health officials. The ACGIH is a professional society established in 1938 by employees of federal or state organizations and educational institutions engaged in occupa- tional health activities. It was formed to meet this obvious need to protect workers from unhealthy workplace environs. The primary goal was to provide a forum for information exchange and to promote actions in the common interest of worker safety (Lippman, 1983). The two major activities of the ACGiH are (1) to determine safe or "acceptable exposure kvels" for work- place chemicals by develapment of threshold limit values (TLVs), and (2) to promote the development of better methods to measure exposure levels, e.g., air sampling instmtnents. The TLVs are recommendations for airborne concentrations of substances which represent conditions under which ACGIH believes that nearly all work- ers tnay be repeatedly exposed daily without adverse health effects. These are not official regulatory standards but rather recommended maximum exposure limits. They ate not absolute safety levels and a small percentage of workers may experience effects at the TLV level or below due to the wide variability in individual susceptibility (ACGIH. 1990). There are three fotms of 1LVa that consider the length of exposure, i.e., TLV-TWA (8-h time weighted average), TLV-ST'E[.(shorttemt exposiae l'unit), and TLV-C (ceiling). The TLV-TWA is an average concentration for anotmsl 8-h workday and a 40-b wod;weekthat workers may be exposed to day atterday. The TLV-STEL is supplementary to the TLV-TWA and consists of a catcentra- tion that worhers can be exposed to for no more than a shortpedod (15 min).11te TWA-STELs protect fmm the acute effects of substances whose primary toxic effects ate of a chronic nature. They are recommended only when acute toxic effects have beenreported itnmhigh, shorttetm exposures of animals orhtmtans. The TLV-C is a contenttation that should not be excaded at any time. ln some cases, such as irritant gases, the 7LV-C may be the onty'iLV category. .r' x G~. :R rai A I Forthosesubsances:, expostne, a large body d provided with a "akin not workers from sldn or muc ' tion has been provided. T. . mtion of carcinogenicity catdttogen tag. As of 1994 ACGH ' - chenticalsubstantxswith' skin notations). Approxin7 Al (confitmed) or A2 (s . oped for several physicr radiofteqnencyhtticrowavc noise, static magnetic fiel•. mendations of the Nation , ments have been adopted 1. OSIiA Act of 197C The concern of the p serious accidents due to ur the Occupational Safety ar to "assure, so far as posatbl had•a safe and healthful federal agenoies, the Occu; and the National Institute : I I OSHA was assigned t: , able standards which dict NIOSH was established to ~ The initial thrust of OSHA. as OSHA federal standatd:- , TLVs were based primarQ eyes or respiratary ttact, ar The 1968 TLVs did nd effects. Sinee then, sddi Ndti careinogenic effects. The 1987) provides informatio, nial substances or process health standards for many of these recommendations A complete listing of 0 1989). I I ~.ai:.~ fal4de' J I I I I
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I I I - 1 I I I I ' I I I ' I I I For those substances that ate absorbedas the tesult of skin, mucous, or eye exposure, a large body dose may tesult: in those cases, the TLVs are also provided with a"stin notation". This alerts employers to the need to protect workers from skin or mucous membrane absorption even if respiratory pnmc- tlon has been provided. Those substances for which there has been a deteani- nation of carcinogenicity are also identified with a"confinned or suspected" carcinogen tag. As of 1990, ACOIH has developed TLV-TWAs for approximately 700 chemical substances with 4ZV-STELs forabout 20% of these (about 20%have skin notations). Approximately 100 of the substatuxs were also designated as Al (confirmed) or A2 (suspected) carcinogens. TLVs have also been devel- oped for several physical agents, including ultrasonic, ultraviolet, laser, radiofiequency/microwave, upper- and ultrasonic acoustic radiations, audible noise, static magnetic fields, heat stress, and hand-amt vibration. Tfie recom- mendations of the National Council for Radiation Protection and Measure- ments have been adopted by the ACGIH for ionizing radiation exposure. 1. OSHA Act of 1970 The concern of the public and Congress over the escalating number of setious accidents due to uncontrolled workplace hazards led to the passage of the Occupational Safety and Health Act (OSHAct) of 1970. The OSHAct was to "assure, so far as possible, that every working man and woman in the Nation had a safe and heaidtful working environment." The OSHAct created two federal agencies, the Occupational Safety and Health Administration (OSHA) and the National lnstimte for Occupational Safety and Health (NIOSH). OSHA was assigned the responsibility for promulgating legally enforce- able standards which dictate practices appropriate to protect workers, while NIOSH was established to conductresearch on occupational safety and health. The initial thrust of OSHA's Standards Program was to adopt the 1968 TLVs as OSHA federal standards for permissible exposure limits (PEI.s). The 1968 TLVs were based primarily on acute effects such as poisoning, irritation of the eyes or tespiratory tract, and skin rashes. The 1968 TLVs did not consider carcinogenic, teratogenic, or mutagenic effects. Since then, additional PELs have been promulgated, most related to carcinogenic effects. The NIOSH Pocket Guide to Chemical Hazards (DHHS, 1987) provides information on the PELs. NIOSH has evaluated many indus- trial substances or processes and has recommended occupational safety and health standards for many of them (DHHS,1988). OSHA has accepted many of these recommendations, rejected a few, and is considering several others. A complete listing of OSHA PELs has recently been published (OSHA, 1989).
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._.2xrb`~,y •n4~...:"'.:a'}'„"~,~.u$.-.,c,~_~°n~'.`~.'. 460 BaaicEnvamrmentalTo.dcofagy TABLE 17.L OSHA Regulated Carcinogens Substance Date of Fuul Standard 2-Acetylnminofloumne iMn4 1/17n8 Actylonitrile h l 4 bi 1129/74 eny •Andno p 6/40186 Asbestas Benzene 9/11187 Benzidine 1/19/T4 Beryllium ' I0117(!5 Bls(chlocomethyl)etlxr IMn4 Coai pitch volaoles . 11t1B3 Coke oven emissions .10/11/16 1,2-Dibtnmethene [EDB] . , . _ 1,2•Dihromo-3~Moecpropsne (DBCPI . .. . 3/17 8 3,3'-Dichlorobenxidloe rzobenzene i i h l 3R9f/4 un no met y 4-D t nzece i h l I129R4 am ~e 4-D met y Ethyleneimine 1/t9l74 Ethykneoxide . ldeh de F 17 y orma In anic arsenic S~ng org 4J4-Methylcnebis{2-chtomandline) [MOCA] (Vaeamd) Methyl chloromethyl ether .. Il29174 a-Napbthylanune Il29(74 (1-Naphtkytamine gd9/74 4-Nitrobipbenyl 1/19174 n-Nitrosodimethylamine , 1/29(14 GS-Propriolactone 1I29774 Trichloraetnyiene (Proposed) Vinyl chloride 101C14(14 . 2. OSHA Regulation of Carcinogens OSHA has now published proposed regulations that identify 28 workplace carcinogens and proposed permissible exposure limits, established work prac- 6ces, and medical surveillance requirements for them. The first substance to be regulated was asbestos in 1972. This was followed in 1973 by a pmposed rnle covering 14 substances, with fmal rules promulgated in 1974. Since that time, proposed rules were issued for 13 other substances. Of the 28 substances proposed as carcinogens, final rules were issued far 26 of them. However, nine of the fmal standards were challenged in coutt and two, MOCA and benzene, were struck down. A reproposed benzene rule has since been finalized. Thus, as of this writing, regulations are in effect for 2S carcinogenic substances as listed in Table 17.1. Realiaag ihe enormous task of promulgating individual standards for the multitude of potential carcinogenic industrial chemicals, OSHA chose to de- velop a generic policy to sttearn]ine the standards r'+i~~~'*.g process. Y11,•~~'FPA f2 la fd3i{'..; ~:_.. ~ 59W a 3. OSHA Cancer Policy Since infonoation was mc developancer. OSHA was coa patentiel canerrhazards and ine exposuns. Toward this end, OS The proposed cancer po, publish a candidate list of pote listed in two categories: catec concem, based on evidence a bioassays, and results that werc tests; category II was for thoss which the evtdence was only ' OSHA thought that a gen. tion of carcinogens by liatitin_ latory proceedings for individ siai) featme of the proposed C ments would not be employed priorities for regulation. It w, declared an occupational carcii on feasibility for control mcas 1980 and consisted of 107 ch were not classified into categc publish an updated candidate 11 I, by categories. Soon after OSHA iasued ic the 1978 OSHA fmal benzene regulate exposures posing a "si then if theregulation could be d prompted C1SHA to amend its c of esemated risk along with fe donal carcinogens (OSHA, 19' cancer policy. In 1982, 05HA (OSHA, 1982) and has not pul Cattcer Policy remains dotmar. 1987, based on additionat data: that demonstrated sigitificant ri 4. OSHA Hazard Comm, Lt 1983, OSHA promulga directing employers in the mn~ M, Y t+ I I ' I I I ~ I I I
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I I I I I I I I I I I I Occupat(unalToxrcolov 461 3. OSHA Cancer Policy Sinoe infonaation was mounting that many workers were at high ri.dc to devebp oa.ncer, OSHA was compeged to find an efficient meens to determine the potential cancerharards and inuoduceteasonable control nteatutesto reduce the exposures. Toward this end, OSHA (1980a) promulgated a generic cancerpoliry. The proposed cancer policy stipulated that OSHA would periodically publish a candidate list nl'potential occupational catcinogens. They were to be listed in two categories: category I was for those substances of the highest concem, based on evidence of carcinogenicity in humans, long term aaimal bioassays, and results that were bt concordance with otherdata, e.g., short term tests; category II was for those which met the criteria for category I, but for which the evidence was only "suggestive". ' I. OSHA thought that a generic aaroinogen policy would speed the regula- tion of carcinogens by l'aniting the debate over genetic issues in future tegu- lamry proceedings for individual carcinogens. An important (and convover- sial) feature of the proposed OSHA policy was that quantitative risk assess- ments would not be employed to set exposure standards but rather only to set priorities for regulation. It was OSHA's intent that once a substance was declared an occupational carciaogen, exposure standards would be based only on feasibility for contml measmes. The first "candidate list" was released in 1980 and consisted of 107 chemicals (OSHA, 1980b). However, chemicals were not classified into category I or II at that timo since OSHA intended to publish an updated candidate list on an annual basis and,would then list them by categories. ' Soon after OSHA issued its cancer policy, the Supreme Court nded against the 1978 OSHA fmal benzene standard and stipulated that OSHA could only regulate exposures posing a "significant" risk to the health of workas and only thenif the regulation could be demonstrated to reduce the risk significantly. This prompted OSHA to amend its carcinogen policy in 1981 to allow consideration of estimated risk along with feasibility in setting health standards for occupa- tional carcinogens (OSHA, 1981). This eviscerated the thrust of the proposed , cancer policy. In 1982, OSHA suspended the publication of the candidate lisit (OSHA, 1982) and has not published one since. As of this writing the OSHA Cencer Policy remains domtant (Note: a final nile was issued for benzene in 1987, based on additional data and the conduct of a quantitative risk assessment that demonstrated significent risk at the previous PE4) 4. OSHA Hazard Communication Standard In 1983, OSHA promulgated the Hazard Cotnmunication Standard (HCS) directing employers in the manufacturing industry to infoxm their employees
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462 Basic F.aoironmentd Tosicology of the hazards with which they work (OSHA,1983).'lhie was modifird in 1987 to expand coverage to employees in ttonmenufaenuing industries (OSHA, 1987). The basic provisions of the HCS consist of hazerd determination, labeling, preparation of material safety data sheets (MSDSs), and employee training. Employers are required to review the available scientific data relative to . the hazardous chemicals that they manufacture or use and to report the infor- tnation m their employees and to those who purchase or use their products. OSHA defined "hazardous chemicals" as • Toxic and hazardous substances for which OSHA has issued a penois- aible exposure standard (29 CFR 1910, subpart Z) • Those for which ACO1H has prepared a TLV • Suspect or confirmed carcinogens as reported by the National Toxicol- ogy Program or International Agency for Research on Cancer (IARC) or those that OSHA has regulated as carcinogens Labeling is required on all storage containers of hazardous chemicals in the workplace and those leaving the workplace. The labels must identify the chemicals, their hazards, and the name and address of the manufacturer or responsible party. Employers are responsible for obtaining or developing a MSDS for each hazardous chemical produced or used in their workplace. The MSDS must contain ' • The identification of the chemical • Physical and chemical characteristics of the hazardous chemical • Known acute and chmnic, health effects and related health information • Exposure limits • Whether the chemical is considered to be a carcinogen by NTP, IARC, or OSHA • Precautionary measures • Emergency and first aid procedures • The identification of the organization responsible for preparing the sheet The MSDSs aro to be readily accessible to employees in the work areas and for manufactured materials, and they must be provided to those purchasing the substances. Excellent reviews by Marsick and Byrd (1990) and Marsick and Adkins (1990) provide further information required of the MSDSs and recommended sources of information for their preparation. Figure 17.1 is the MSDS fotmat recommended by OSHA. .. In addition to labeling and MSDSs, the employers are also required to establish a training and information program for employees exposed to I
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M m m m m mm mm m m ar .r. .rr ... .= r ... o. MATERIAL fAFEty DATA SHEEf eo..'.yruuwurw ' GIMIIYnwbWNY YIr 1L m1' M.~.Fw~1.r~w bIM/4 /mIXV ~ K~{ RiBbi~ /l1 . r.~..n6 u.u.1.. a.r. ww fMWR ~ 0 rT~YG"h~rr >Wt •~n Ty.nir .rr~•o I , , aaYR 1~,111, wmm~~ WRT=;WFMmi= ~ ~ n - l-'''-Iw1G - . ~~ F~ Fylun 1T•1. RaanvKndcd fpm.n fnr cutahl rfay dna f6eq (fJ6FIA). 6 . ..... . . ...__.__. . .._......~ . . _ I. T11 M4t~lr 1 ~V•- . .. . ...r.... ~..... ..,~. _ _. ~............",',7'1'f:^'.r.r:.-'1•r~•.^^--'~~~.„,c,.~~„~.t-_-- i !:: J •I IS Ib ~ ~+{lr~rs~'' _..:..Irr.l64: UiiAa':!rrei,l: . Lrr•r6,i:QH+1•lULt•:• " ~91... -._• T Jl 1 L + t: 01e d- A . 4 : ' • ~ , , d ~ u~l.u ') .~rLi ~lytc -e.t~ ~i.Y~\fta/4..dL bL9bBL A ~ -- E90Z
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464 Basic Envirenmenml Ta:icology hazardous chemicals in their work area at the time of initial assignment and whenever a new hazard is introduced into their work area. A training plan is required which will train employees in the reading and interpretation of labels and MSDSs and instmct employees in obtaining and using the avail- able hazard information. 5. Emergency Planning and Community Right-to-Know Act Regulations have also been promulgated extending the dissemination of infonnationon chemicals used in industry to the public residing nearby the industrial facilities. Title IIl of the CERCLA Superfund Amendments and Reauthorization Act of 1986 (SARA) requires that indusrty inform the public regarding these hazardous chemicals (U.S. EPA, 1988). The responsible industry must • ProvideatepresentativetoarequiredLocalEmagencyPlamdttgCom- ntittee (LEPC) • Notify the LEPC in the event of a release to the environment of a listed hazardous substance that exceeds the reportable quantity (RQ) for that substance • Submit copies of MSDSs or a list of MSDS chemicals to the Ld:PC, State Emergency Response Commission, and local fire departments . ReporttotheLEPCanyhazardouschemicals(forwhichOSHAMSDSs have been prepared) that were present in the facility at any time during the year at a level above the specified thresholds • Report annually to the EPA and state officials an inventory of chemi- eals that have been released to the environment in excess of specified threshold quantities . In addition to the Federal OSHA and SARA requirements, many states have "Right-to-Know" laws. The occupational health specialists must be cog- nizant of state and local regulations and assure compliance with those provi- sions as well as the federal requirements. C. MEASUREMENT OF OCCUPATIONAL EXPOSURES To assure compliance with the TLVs or PEi.s, knowledge of individoal worker exposures are needed. Assessment of the exposure to chemical agents primarily involves three approaches: (1) examination of exposure records, (2) environmental monitoring, and (3) biological monitoring. Records that can be used as a source of exposure data ate industrial tecordv, information from I suppliers (such as MSDSs), t data provided by the coml~S Data ftom such soutms ue r: directing tttote definitive eff, monitoring. L Environmental Monf I The two main types of r sampling and pers®al samp I area sampling, the measurem, fixed stations or areas, e.g., r pling can detect sources of e Area sampling, coupled with i various areas where the exf sufficiem to estimate a persc; pling to estimating individua{ sures have multiple mlease , tions. Workers usually move ner, so detailed recordings of . sampling can also detect'Yug9' loss of containment or contm] of temperature control of a va, the fugitive emission at the detection by fixed sensors in~ or remote indicators are noi~ chemicals, e.g., hydrogen sull gen dioxide, sulfur dioxide, c' and continuing general area I concentrations at speci5c loc mielY detetmine the individu I I I I I The advantages of gene exposure can be pinpointed , collect very large samples analytic devices. They are necessary. Many monitors at excessive. On the other ban require well trained technicia: that to relate general aeos mc individttal's work pattem integrate their exposures. A ~ the use of "grab samples". S can collect larger volumes at ;t¢ T_VR~?., _ ~. w.~ v N b rs~,: tn I I I
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I I I I ' I I I I I I I I I I I I suppliers (such as MSDSs), data pertaining to environmental discharges, and data provided by the company, its iruorance canier. and government agencies. Data ftom such somas are rather quafltative in nature but can be valuable in divecting mase definitive efforts for environmental monitoring or biological mooiioring. 1. Environmental Monitoring The two main typrs of environmental monitors consist of general am sampling and personal sampling (Hermatm end Peterson, 1988). in general area sampling, the measurements am not specific for individuals but rather for fixed stations or areas, e.g., oear machines and equipment. This type of smn- pling can detect sources of exposure or points of releasm e.g., welding ares. Area sampling, coupled with knowledge of awmker's activity (time present in various am where the exposures have been documented), ean often be sufficient to estimate a person's exposure profile. Extrapolation of am sam- p]ing to estimating individual exposure is rarely a simple matter. Most expo- sures have multiple release points with complex spatial and temporal varia- cons. Workers usually move through the workplace in a nonpredictable raan- ner, so detailed recordings of such movements are needed (Lynch, 1979). Area sampling can also detect "fugitive emissions", leaks or inadvertent and random loss of containment or control (e.g, due to plugged drain, inoperative fan, loss of temperature control of a vat, etc.). Constant monitoring is desirable to detect the fugitive emission at the earliest time and prevent bxtensive injury. Leak detection by fixed sensors in critical locations which are connec[ed to alarms or remote indicators are now commonly used for some of the more toxic chemicals, e.g., hydrogen sulflde, carbon monoxide, hydrogen cyanide, nitro- gen dioxide, sulfur dioxide, chlorine, and other highly toxic agents. Extensive and continuing general area sampling must record temporal IIuctuations of concentrations at specific locations to relate to worker movements and accu- rately determine the individual exposure profile. The advantages of general area sampling are that the main souttts of exposure can be pinpointed and the monitoring equipment can be rigged to collect very large samples and can be coupled with automatic recording and analytic devices. They are adequate when precise worker exposure is not necessary. Many monitors are capable of issuing alerts when exposures are excessive. On the other hand, some area monitors are quite complex and require well trained techniciaris forps.oper use and maintenance. Keep in mind that to relate general area monitoring results to aa individual's exposure the individual's work pattern and specific areas worked must be recorded to integrue their exposmes. A variation of area monitoring at fixed locations is the use of "gtab samples". Such area sampling is done on an ad hoc basis and can collect larger volumes at specific locations as the need watrants. I

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