11 Evaluation of Organic Solvent Vapors in the Workplace
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ROBERT C. VOBORSKY Sentry Insurance, 1800 North Point Drive, Stevens Point, WI 54481
A potential threat to the health, productivity, and efficiency of man in most occupations and industries, and in his nonoccupational environments as well, is his exposure to organic solvents. Exposures to solvents occur throughout life from conception to death. Solvent vapors inhaled by the mother often reach the fetus. The elderly often spend their last days in the hospital where the odor of the solvents, disinfectants often prevails. Exposures also occur in the course of daily living. Exposures may range from the inhalation of vapors from a newspaper freshly off the news stand, to the intake of the cleaning solvent by a l l routes of exposure being used. Effects from the exposure may range from simple objection to a low concentration odor, to death at high concentrations. In between, there is a whole spectrum of effects. When one considers that there are hundreds of different solvents, that there are a multitude of exposures to different concentrations, and that these effects may differ from individual to individual and may also vary with age, i t is apparent that the number of combinations almost defies imagination and description. The problem lies in determining what are the effects, which are harmful and which are not harmful, and at what levels such effects occur. When the exposure exceeds certain threshold levels, many of these effects are harmful to ones health and his ability to function efficiently may be impaired. In some cases, the effects are irreversible and damage to the body organ can be permanent. As i n the case of many s a f e t y measures, people o f t e n do not u t i l i z e the necessary p r o t e c t i v e measures. Too o f t e n there i s more contact with the s k i n then the user r e a l i z e s and/or l o c a l v e n t i l a t i o n i n the b r e a t h i n g zone i s not adequate. Concentrations of organic solvent vapors i n a i r are u s u a l l y expressed i n p a r t s of vapor per m i l l i o n parts of a i r (PPM). The p h y s i o l o g i c a l e f f e c t s of d i f f e r e n t solvents i s f a r to complex and v a r i a b l e to be discussed here i n depth. However, 0-8412-0539-6/80/47-120-197$05.00/0 © 1980 American Chemical Society In Analytical Techniques in Occupational Health Chemistry; Dollberg, D., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1980.
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c e r t a i n g e n e r a l i z a t i o n s can be made. A l l organic solvents a f f e c t the c e n t r a l nervous system to some extent, a c t i n g as depressants and a n e s t h e t i c s , and causing other e f f e c t s depending upon the degree o f exposure and the solvent involved. These e f f e c t s may range from mild unnoticed e f f e c t s to n a r c o s i s and death from r e s p i r a t o r y a r r e s t . A l l solvents which contact and wet the s k i n w i l l cause d e r m a t i t i s , an inflammation of the s k i n . This may be caused by simple i r r i t a t i o n or by systemic damage to the s k i n . Even the most i n e r t solvents w i l l d i s s o l v e the n a t u r a l p r o t e c t i v e b a r r i e r of f a t s and o i l s and leave the s k i n unprotected against f u r t h e r i r r i t a t i o n and harm by the organic solvent. Organic solvents are u s u a l l y c l a s s i f i e d according to t h e i r chemical composition. The a l i p h a t i c hydrocarbons, which are s t r a i g h t or branched chains saturated with hydrogen, a c t p r i m a r i l y as depressants to the c e n t r a l nervous system, but otherwise they are g e n e r a l l y as i n e r t b i o c h e m i c a l l y as they are chemically. Even as a i r p o l l u t a n t s , they are among the l e a s t r e a c t i v e and do not pose a s i g n i f i c a n t problem. The primary problem with t h i s c l a s s of solvents i s d e r m a t i t i s . The c y c l i c hydrocarbons, such as cyclohexane, a c t much i n the same manner as the a l i p h a t i c hydrocarbons. A s i g n i f i c a n t percentage of q u a n t i t y inhaled may be metabolized to compounds with a lower order of t o x i c i t y . The unsaturated c y c l i c hydrocarbons g e n e r a l l y are more i r r i t a t i n g than the saturated forms. The primary problem i s d e r m a t i t i s . The aromatic hydrocarbons, such as xylene and toluene, e x h i b i t t h e i r t o x i c e f f e c t s on the c e n t r a l nervous system. Benzene, however, i s q u i t e d i f f e r e n t i n that i t ' s t o x i c i t y a f f e c t s the blood forming organs. The e f f e c t s of the halogenated hydrocarbons vary considerably with the number and type o f halogen atoms present i n the molecule. Carbon t e t r a c h l o r i d e a t one end of the s c a l e i s h i g h l y t o x i c , a c t i n g a c u t e l y by i n j u r y t o the kidneys, the l i v e r , the c e n t r a l nervous system and the g a s t r o i n t e s t i n a l t r a c t . Trifluo r o t r i c h l o r e t h a n e on the other hand has a very low l e v e l o f t o x i city. I t s primary e f f e c t of known s i g n i f i c a n c e i s the depressant e f f e c t on the c e n t r a l nervous system. The c h l o r i n a t e d hydrocarbons i n general are more t o x i c then the common f l u o r i n a t e d hydrocarbon s o l v e n t s . S p e c i f i c e f f e c t s and t o x i c i t i e s vary widely, but the most common e f f e c t s from the c h l o r i n a t e d hydrocarbons of intermediate t o x i c i t y are the depressant e f f e c t on the c e n t r a l nervous system, d e r m a t i t i s , and i n j u r y to the l i v e r . The nitro-hydrocarbons vary i n t h e i r t o x i c o l o g i c a l e f f e c t s depending on whether the hydrocarbon i s a p a r i f f i n or an aromatic. The p a r i f f i n s are known f o r t h e i r i r r i t a n t e f f e c t s accompanied by nausea, and the e f f e c t s on the c e n t r a l nervous system and l i v e r becoming s i g n i f i c a n t with acute exposures. The n i t r o - a r o m a t i c s l i k e nitrobezene, are much more hazardous.
In Analytical Techniques in Occupational Health Chemistry; Dollberg, D., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1980.
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The common ketones g e n e r a l l y exert a n a r c o t i c type a c t i o n . A l l are i r r i t a t i n g to the eyes, nose, and the t h r o a t , and f o r t h i s reason high concentrations are not u s u a l l y t o l e r a t e d . (1)(2) Personnel concerned with h e a l t h and s a f e t y should recognize that the use of organic solvents can be a major t h r e a t to h e a l t h , and that c o n t r o l s are o f t e n necessary to prevent detrimental physiological effects. The Occupational Safety and Health Act of 1970 ( P u b l i c Law 91-596) i s one of the most f a r - r e a c h i n g f e d e r a l laws ever enacted. I t a p p l i e s to a l l employees of an employer engaged i n a business e f f e c t i n g commerce, except f o r government employees and employees and employers at employment s i t e s being regulated under other f e d e r a l laws. The Act s p e c i f i e s the employer's o b l i g a t i o n s to f u r n i s h to each employee a place of employment f r e e from the recognized hazards that are causing or l i k e l y to cause death or serious p h y s i c a l harm and to comply with standards promulgated by the Occupational Safety and Health A d m i n i s t r a t i o n (OSHA). The r e s p o n s i b i l i t y includes the determination of whether a hazardous c o n d i t i o n e x i s t s i n a workplace, the e v a l u a t i o n of degree of the hazard and where necessary, the c o n t r o l needed to prevent occupational illness. In the f i e l d of i n d u s t r i a l hygiene, c o n t r o l of the work environment i s based on the assumption t h a t , f o r each substance, there e x i s t s some safe or t o l e r a b l e l e v e l of exposure below which no s i g n i f i c a n t l y adverse e f f e c t occurs. These l e v e l s , r e f e r r e d to i n the generic sense as t h r e s h o l d l i m i t values (TLV) r e f e r to airborne concentrations of substances and represent c o n d i t i o n s under which i t i s b e l i e v e d that n e a r l y a l l workers may be r e peatedly exposed day a f t e r day without adverse e f f e c t . The TLV i s a Time Weighted Average (TWA) concentration f o r an e i g h t hour workday or f o r t y hour work week. Industry must comply with the Threshold L i m i t Values regarded by the r e g u l a t o r y agency as standards f o r occupational exposure to chemical substances. The l i s t of chemical substances which have been assigned a t h r e s h o l d l i m i t appears i n S e c t i o n 1910.1000 (e) Tables Z - l , Z-2, and Z-3 of the F e d e r a l R e g i s t e r . To a i d i n d u s t r y i n a monitoring program designed to comply with these standards, the N a t i o n a l I n s t i t u t e f o r Occupational Safety and Health (NIOSH), developed methods f o r the c o l l e c t i o n and a n a l y s i s of those r e s t r i c t e d compounds. Method P&CAM-127 i n the NIOSH Manual of A n a l y t i c a l Methods describes the recommended method of c o l l e c t i o n and a n a l y s i s of organic solvents i n a i r . (4) Many of the common solvents used i n i n d u s t r y which have been r e s t r i c t e d because of t h e i r t o x i c i t y are l i s t e d i n TABLE 1. The f i r s t step i n r e c o g n i z i n g p o t e n t i a l problem areas i n an occupational environment using organic solvents i s to become f a m i l i a r with the p a r t i c u l a r operations and raw m a t e r i a l s i n the p l a n t . Knowledge of the process and equipment as w e l l as the raw materials i s v i t a l . Process flow sheets from the p l a n t should be
In Analytical Techniques in Occupational Health Chemistry; Dollberg, D., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1980.
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