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Also known as: Methyl chloroform, 1,1,1-TCA
Chemical reference number (CAS): 71-55-61

1,1,1-TCA is a colorless liquid that evaporates quickly at room temperature. It is used as a metal degreasing and dry-cleaning solvent, and to make other organic chemicals. 1,1,1-TCA can also be found in aerosol spray products found in the home. When 1,1,1-TCA enters the environment, it can seep into soil and groundwater or evaporate into the air.

People can be exposed to 1,1,1-TCA when they inhale contaminated air. This is the most common type of exposure that occurs in the workplace. If people have contaminated drinking water in their home, they may be exposed to vapors when using water to cook, bathe, or do laundry. 1,1,1-TCA can enter the body when people drink contaminated water. Although, vegetables do not take up the chemical when they are grown in contaminated soil.

1,1,1-TCA can be absorbed through the skin when people use products that contain the chemical, handle contaminated soil, or bathe in contaminated water.

No standards exist for regulating the amount of 1,1,1-TCA allowed in the air of homes. However, the Wisconsin Department of Natural Resources (DNR) has set a residential indoor air action level for 1,1,1-TCA at 940 parts per billion by volume (ppbv). The action level is considered to be protective of public health. Breathing 1,1,1-TCA for a lifetime at 940 ppbv is very unlikely to be harmful to people. If 1,1,1-TCA concentrations in air are above the action level, we recommend taking action to halt exposure.

Most people can't smell 1,1,1-TCA until the level is greater than 23,000 ppbv. If you can smell the chemical, the level is too high to be safe.

The Wisconsin Department of Natural Resources regulates the amount of 1,1,1-TCA that can be released into outdoor ambient air by industries.

The state and federal drinking water standards for 1,1,1-TCA are both set at 200 parts per billion (ppb). We recommend that you stop drinking water that contains more than 200 ppb of 1,1,1-TCA. Contact your local public health department for more information specific to your situation.

Everyone's Reaction is Different

A person's reaction to chemicals depends on several things, including individual health, heredity, previous exposure to chemicals including medicines, and personal habits such as smoking or drinking. It’s also important to consider the length of exposure to the chemical, the amount of chemical exposure, and whether the chemical was inhaled, touched, or eaten.

The following symptoms may occur immediately or shortly after exposure to a level of 1,1,1-TCA above 350 ppm in air:

  • Irritation of the eyes, throat and nose
  • Headaches, nausea and dizziness
  • Loss of balance
  • Loss of consciousness
  • Heartbeat irregularities
  • Drop in blood pressure

Animal studies show that exposure to 1,1,1-TCA is not likely to cause cancer; however, liver, lung, and brain damage can result from long-term or high-level exposures.

For those individuals with frequent or potentially high-level exposures, liver function tests and neurological examinations may be performed. A medical evaluation that includes a careful history of past and present symptoms will provide a basis for future health exams.

Seek medical advice if you have any symptoms you think may be related to chemical exposure.

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Last revised June 15, 2022