Solvent Exposure in the Workplace

Solvents are probably the most widely used substances in the workplace and among the most dangerous.

Organic solvents can cause cancers, heart and blood diseases, brain damage, nervous disorders, liver and kidney damages, and affect one's ability to bear healthy children.

Whether you produce solvents, use them as degreasers, or as intermediates in chemical synthesis, be sure to know what solvents are used, what their health effects are, and how to protect yourself from the hazard. The following is an overview of the major hazards with a chart listing solvents according to chemical families and listing OSHA exposure limits, organs affected, and the health risks.

One point should be made: the exposure limits are not always a good clue to the toxicity of the solvent. Most of the exposure limits were set without any clear idea of whether the limits were actually protective. Most of the limits need to be lowered, especially for hydrocarbons. You need to insist that the company keep levels to a minimum, and this article tells you how.

Health Effects

Central Nervous System

Solvents damage the central nervous system (CNS) through their ability to cause narcosis or depression. Symptoms of CNS poisoning include inebriation followed by headache and nausea. If exposures are high enough, dizziness, convulsions, and unconsciousness can occur. Chronic exposure to low levels may cause loss of appetite, irritability, fatigue, and personality changes.

Methyl butyl ketone, carbon disulfide, and n-hexane are solvents that also damage the peripheral nervous system, causing a slowdown in the speed of the nerve impulses from the spinal cord to the arms and legs. The result is peripheral neuropathy, a disease marked by numbness, weakness and even paralysis of the arms and legs.

Heart Damage

The discovery of over 100 deaths from sniffing solvent containing products in one five-year period led to the link between heart disease and solvent exposure. Several of the hydrocarbon solvents cause abnormal heart rhythms Or "arrhythmias". Benzene, chloroform, heptane, trichloro-ethylene, carbon tetrachloride, methylene chloride, and methyl chloroform all have the ability to cause arrhythmias in exposed workers. Tetrachloroethylene has caused arrhythmias in animal experiments.

Liver and Kidneys

The liver serves to convert solvents into less toxic substances, and the products of the conversion are excreted by the kidneys. As a result, both organs, but especially the liver, are affected by solvent exposure. Liver damage may lead to complaints of loss of appetite, nausea, an unpleasant taste in the mouth, and stomach discomfort. Kidney failure can occur after acute or long-term chronic exposures.

Solvents and cancer

A Finnish study of workers exposed to the halogenated hydrocarbons 1,1,1-trichloroethane, tetrachloroethylene, and trichloroethylene showed an excess risk of various cancers. These include cancers of the liver, pancreas, lung, kidney, bladder, nervous system, and blood-forming system, as well as the cervix uteri.

An excess of cervical cancer has been consistently reported for female solvent workers. This has usually been explained by socioeconomic factors, but there appears to be an occupational component present.

Solvents and pregnancy

Maternal and paternal exposure to organic solvents affects pregnancy outcome, but inconsistently.

In a study of pharmaceutical workers, the risk of spontaneous abortion increased with the number of solvents used. In pharmacy assistants, solvent exposure was associated with an increased risk for stillbirth and perinatal deaths.

Individual solvents
An increased risk of spontaneous abortion was linked to exposure to tetrachloroethylene in dry cleaning work.

Occupational exposure to toluene was related to spontaneous abortion in a small group of shoe workers. An increased risk for spontaneous abortion was also found among audio speaker factory workers and laboratory workers with high exposure to toluene. An excess of urinary tract defects was reported for toluene exposure.

High exposure to aliphatic hydrocarbons was related to spontaneous abortion among women monitored for solvent exposure; the risk was highest among graphics workers.

Other solvents
An increased risk of spontaneous abortion has been linked to exposure to petroleum ether in laboratory work, methylene chloride in pharmaceutical manufacturing work, and paint thinners.

Paternal exposures

Paternal exposure to organic solvents has been related to spontaneous abortion, low birth weight, and birth defects. The highest risks were observed among painters and wood workers. Individual solvents associated with spontaneous abortion included toluene, xylene, and miscellaneous solvents such as thinners.

Exposure to solvents used in petroleum refineries and in the manufacture of rubber products was found to be related to spontaneous abortion.

Paternal studies have been marred by lack of accurate exposure data, but the above offers a hint of the problems posed by paternal exposures.

Irritation

All solvents are irritants. Inhaling the vapor can cause irritation of the eyes and upper respiratory tract, including the nose and throat. Eventually, the irritation will cause chronic bronchitis and other lung diseases.

Skin contact with solvents can dissolve the skin's natural protective coating, causing dryness, chafing, and cracking. This makes the skin more vulnerable to other irritants and often leaves the skin open to absorption of toxic chemicals.

Fire and Explosion

Engineering Substitution of a less hazardous solvent is often an effective way of minimizing the risk to workers. Where possible, solvents should not be used at all when detergents and water will do the job. When substituting one solvent for another, however, make sure that the substitute is indeed less toxic than the original. If you have doubts, contact the Health and Safety Department for assistance.

Enclosing the process where the solvent is used is the most effective engineering control of solvent vapors. Local exhaust ventilation should also be used to prevent vapor release through openings in the enclosure.

If the operation cannot be enclosed, the local exhaust ventilation should be used to remove vapors at the source. This consists of a hood or slot placed near the solvent generating source. The ventilation system should be checked out at least every three months, more often if exposure levels are high. The company should conduct regular air monitoring and provide you with the results. If exposure levels are high, the ventilation is inadequate and needs improvement.

Personal Protective Equipment

Personal protective equipment should be provided by the company at no expense to the worker and should include gloves, face shields, aprons and any other clothing necessary to protect from solvent skin contact. The company should launder any clothing provided and install separate lockers for work and street clothing.

The company should also allow workers shower and clean-up time before leaving work at the end of a shift.

Respiratory protection should only be used as a temporary control measure, or for special situations such as cleaning up spills, cleaning tanks, or during startup and shutdown operations.

Work Practices

  • All solvent containers should be properly labeled with the composition of the solvent and safe handling procedures.
  • Employers should be informed of the toxic and flammable characteristics of all solvents in use, as well as their recommended control measures.
  • Written standard operating procedures should be posted, including first aid instructions, wherever solvents are handled or used.
  • Solvent-soaked rags should be disposed of in air-tight, all metal containers and removed from the plant daily.
  • Eating facilities should be separate from work areas.
  • Ventilation should be checked regularly to insure it is adequate and working.

    Are You Exposed to Solvent Mixtures?

    Since there are so many organic solvents, the possibilities for combined exposures in the work environment are numerous.

    The individual concentrations of organic solvents in the workplace can be well within the OSHA PEL, yet still cause health problems as several recent studies have demonstrated.

  • A high prevalence of polyneuropathy, a nerve disturbance, was noted in 350 male and female shoe and leather workers exposed to different solvents in glues. There was a relationship between the daily duration of glue use and the intensity of nerve disturbances. Symptoms of polyneuropathy included muscle spasms, leg weakness and pains, and tingling in the arms. The solvents used included n-hexane, ethyl acetate, trichioroethylene, n-heptane, and traces of benzene, toluene and xylene.
  • One hundred workers in two handicraft shops were exposed to a solvent mixture containing low concentrations of ace tone, butylacetate, and toluene (below the PEL). Almost 95% of the employees had complaints of headache, sleeplessness, digestive disturbance, and signs of irritation. Many of the women workers reported spontaneous abortions, premature births, and menstrual cycle disturbances.

    Solvent Questionnaire

    1. Are you abnormally tired?
    2. Do you have palpitations of the heart even when you don't exert yourself?
    3. Do you often have painful tingling in some part of your body?
    4. Do you often feel irritated without any particular reason?
    5. Do you often feel depressed without any particular reason?
    6. Do you often have problems with concentrating?
    7. Do you have a short memory?
    8. Do you often perspire without any particular reason?
    9. Do you have any problems with buttoning and unbuttoning?
    10. Do you generally find it hard to get the meaning from reading newspapers and books?
    11. Have your relatives told you that you have a short memory?
    12. Do you sometimes feel a tightness in your chest?
    13. Do you often have to make notes about what you must remember?
    14. Do you often have to go back and check things you have done such as turned off the stove, locked the door?
    15. Do you have a headache at least once a week?
    16. Are you less interested in sex than what you think is normal?

    Less than 28 years of age, with more than four symptoms in the 16 questions, should be further checked by a physician.

    28 years of age or older, more than six symptoms should be further checked by a physician.

    Local Union Action Plan

    1. Request from your employer a list of all solvents used in the plant.
    2. Rank the solvents in order of toxicity.
    3. Survey the member ship for adverse health effects from solvent exposure. (Use the survey in this Alert).
    4. Demand substitution of less toxic solvents where necessary and possible.
    5. If you need assistance, contact your International representative, who will get in touch with the Health and Safety Department.

    SOURCES:

    OCAW Lifelines.
    Journal of Occupational & Environmental Medicine, August, 1995, Vol.37, No. 8.
    Bureau of National Affairs (BNA) Occupational Safety and Health Daily.
    Axelson, Olav, M.D., Hogstedt, Christer, M.D., On the Health Effects of Solvents, The Chemical Occupational Environment.

    Published by the Oil, Chemical and Atomic Workers International Union, P.O. Box 281200 Lakewood, CO 80228-8200.