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.