Examples of such solvents include kerosene, acetone, petroleum distillates and naphthas. Potential solvent uses are limitless and include degreasing, cleaning, stripping, thinning and finishing. Solvents are used extensively in many industries.
How Can Exposure To Solvents Affect Health?
Excessive solvent exposures can lead to health problems.
Solvents are ABSORBED (enter the body) by the following routes:
Inhalation
This is the most important route of exposure for most solvents. Once inhaled, the vapors which arise from solvents can directly irritate the upper respiratory tract (nose, throat and bronchial tubes) and the lungs. Solvent vapors can also be easily absorbed from the lungs into the bloodstream and travel to other parts of the body to produce additional harmful effects.
Skin Contact
Solvents can be absorbed through the skin and travel to other parts of the body. Solvents can also break down the natural protective oils and fats of the skin. This can cause the skin to become dry, cracked and inflamed.
Mouth Contact
Solvents can enter the body and bloodstream through the mouth and digestive system. Although not a common route of entry, mouth contact with contaminated hands, food and cigarettes can occur and be dangerous.
Health Effects Are Dependent On What Factors?
Toxicity of the solvent.
Route of exposure.
Amount of exposure.
Individual worker's susceptibility.
Combination with other chemical exposures.
All of these factors are important in determining whether a person will experience any damaging health effects from solvent exposures. For example, a worker who already has respiratory breathing problems, such as asthma, may experience breathing difficulties while working around solvent vapors that do not produce any health effects in a person without respiratory problems.
What Acute (Short-Term) Effects Can Occur?
Solvent health effects that are ACUTE follow a single or short-term chemical exposure and usually occur soon after the exposure. Acute effects generally last only minutes, hours or days and are reversible once the exposure is over. Since they occur shortly after exposure, they are more easily identified. Common acute effects from solvent exposure include:
Respiratory Irritation
Exposure to solvent vapors can irritate respiratory mucous membranes. This can produce a burning sensation of the nose, throat or chest and lead to coughing. Inhalation of very high concentrations of solvents may result in severe irritation of the lungs and a condition called pulmonary edema, or fluid in the lungs. Symptoms of pulmonary edema include coughing and difficulty in breathing and require prompt medical attention.
Eye Irritation
Exposure to high concentrations of solvent vapors may produce eye irritation. This can lead to burning, tearing, and painful eyes. Dermatitis. Acute contact with a solvent can cause a breakdown of protective fats and oils in the skin. Skin may become reddened, itchy, and blistered. Central Nervous System Depression. The central nervous system consists of the brain and spinal cord. Solvent exposure can affect the brain like alcohol and lead to a state similar to being drunk. Large exposures can produce central nervous system effects including euphoria, feeling "high," dizziness, lack of coordination, headaches, fatigue and nausea.
Heart Arrhythmia
Solvents, particularly chlorinated hydrocarbons (those with chlorine molecules attached to carbon), can increase the irritability of the heart muscle at high exposure levels. This can lead to irregular heartbeats called cardiac arrhythmia.
What Chronic (Long-Term) Effects Can Occur?
Solvent exposures can produce CHRONIC health effects, which occur after repeated exposures and are often long-lasting or irreversible. Symptoms may appear gradually, so they may be initially ignored. This can make it hard to identify the chronic health problems related to solvent exposure.
Chronic health effects include:
Respiratory Effects
Repeated irritation of the respiratory tract may result in bronchitis and produce symptoms of chronic cough and sputum production. Dermatitis. Long-term exposure can lead to chronic dermatitis. The skin can become dry, thickened, cracked, hardened and flaky.
Nervous System
Most organic solvents affect the central nervous system, primarily the brain. With increasing levels of exposure, these effects include feeling "high," irritability, nervousness, weakness, tiredness, dizziness, sleeplessness, disorientation, confusion and even unconsciousness.
Long-term exposure has been associated with effects such as difficulty in thinking and personality changes. A few solvents, such as n-hexane and methyl n-butyl ketone, can damage the peripheral nerves, which are nerves to sensory organs and muscles. Symptoms of nerve damage include pain, loss of sensation, and weakness, usually beginning in the toes, then the fingers and moving up the legs and arms.
Liver
Some solvents, particularly chlorinated types, can damage the liver, causing a type of hepatitis. There may be no symptoms. If there are symptoms, they may include: nausea, pain in the right side, yellow skin and eyes, dark urine and light-colored bowel movements. Hepatitis may be detected by blood tests of liver function.
Blood
A few solvents, such as glycol ethers, affect the blood, either by damaging blood cells that are circulating in the body or decreasing the production of new blood cells. There usually are no symptoms until blood counts are extremely low, resulting in tiredness or infections. Benzene is one solvent that is known to be particularly dangerous; it can cause anemia (low blood counts) and also leukemia (cancer of the white blood cells).
Reproductive Effects
Although chemicals may affect reproduction in females and males, there are no definitive studies that demonstrate the effects of solvents on human reproduction. Cancer. Benzene is the only commonly used solvent that has been associated with cancer in exposed workers. A number of other solvents, including carbon tetrachloride, chloroform, 1,4-dioxane and trichloroethylene have caused cancer in laboratory animals. Vinyl chloride has been known to cause angiosarcoma of the liver in humans.
What Should You Do If You Develop Symptoms That May Be Related To Solvent Exposure?
Inform your employer and consult a physician. Many health problems that can be related to solvent exposures can also be caused by other medical problems which may need immediate treatment. Special laboratory tests can be performed to assess solvent exposures.
How Can Exposure To Solvents Be Reduced or Prevented?
The best way to guard against the harmful health effects of solvents is to prevent or minimize exposure. As a first step, be aware of the hazards and safe handling procedures for materials on the job. This information must be available to you and usually is provided in Material Safety Data Sheets (MSDS), employer instructions and container warning labels.
Secondly, use the procedures and equipment that are available. Employers are responsible for providing safe work conditions.
The most important ways of preventing exposure are:
- Substitution of a solvent with a less hazardous substance.
- Enclosure of the process or containers where the solvent is being used (so it never enters the air you breathe).
- Exhaust ventilation systems that function effectively.
- Redesign of a process (to eliminate a step releasing vapors or requiring liquid contact).
- Personal protective equipment (should be used only when engineering controls such as enclosure of a process are not feasible).
- Respirators should be worn as a part of a comprehensive respiratory protection program. Other protective gear such as gloves, aprons, goggles and face shields should be used when appropriate.
- Good housekeeping practices (essential to ensure exposures are minimal).
What Other Hazards Are Posed By Solvents?
Solvents can be flammable or explosive, and exposing them to flame or hot surfaces can also form highly toxic decomposition products. Ignition sources such as welding torches, lit cigarettes and sparks should be kept away from solvent use and storage areas. I
n addition, some chemicals are incompatible with solvents and mixing will produce toxic gases, heat or fire. Oxidizers (e.g., sodium chlorate) and strong acids and bases (e.g. sulfuric acid, sodium hydroxide) should never come in contact with solvents. Refer to Material Safety Data Sheets or chemical suppliers' information for special hazards.
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