Perc poses a serious threat to human health. For example, the U.S. Environmental Protection Agency (EPA) listed perc as a Hazardous Air Pollutant and both the U.S. EPA's Carcinogen Assessment Group and the International Agency for Research on Cancer (IARC) classify perc as a probable human carcinogen.

Studies of dry cleaning workers have found an association between a wide array of serious health effects and exposure to perc in the workplace. Perc is known to attack the central nervous system -- workers in perc dry cleaning plants frequently complain of headaches, nausea, dizziness, irritability, and other problems related to the central nervous system. Liver and kidney damage has also been linked to perc.

Exposure to perc is also suspected as the cause of a myriad of reproductive disorders. Studies in Scandinavia have shown an association between occupational exposure to perc and higher rates of miscarriage in dry cleaning workers. Infertility in both men and women and menstrual disorders have been linked to perc as well.

Studies of dry cleaning workers have also found an association between exposure to perc and increased risk of several types of cancer, including cancer of the esophagus, kidney, liver, bladder, lung, cervix, and pancreas, as well as leukemia.

Widespread human exposure to perc from the dry cleaning industry is occurring throughout our population, through contaminated air, water, and food. Once inhaled or ingested, perc accumulates in the body, although it is not as persistent as some other organochlorines. It has been found in the blood, fatty tissue, breath, and breast milk of the general U.S. and Canadian populations.

Also at high risk are people who live in close proximity to dry cleaning plants. Perc levels tens or hundreds of times higher than New York State guidelines have been found in residences in New York and California --the only two states to have tested indoor air levels. New York City now bans the operation of drycleaning shops in residential buildings. High perc concentrations in homes poses a severe threat to public health as many people spend more than 40 hours per week at home, and therefore are exposed to perc for even longer periods than dry cleaning workers. Some groups, such as small children and the elderly, may spend substantially more time at home.

Perc from dry cleaning plants is also contaminating food and water supplies. Numerous investigations of perc-contaminated groundwater, for example, have been linked to dry cleaners. Tests done on food from stores or residences near dry cleaning plants have revealed high levels of perc contamination as well. Because perc accumulates in fatty tissue, infants can be exposed through contaminated breast milk.

Even casual exposure to dry cleaned clothes can be a cause for concern. Dry cleaned clothes offgas perc, resulting in higher perc levels wherever the clothes are placed such as in the home or car. Tests of food stored in a closed car with dry cleaned clothes for as little as one hour have revealed elevated levels of perc.

Increasing evidence of perc's adverse health effects, coupled with new realizations of widespread public exposure, have resulted in a number of recent regulatory actions by some governments and local authorities. Dry cleaners using perc face high liability costs in the U.S. for any site or groundwater contamination caused by their operations. Recently, several perc-contaminated groundwater supplies in both the U.S. and Canada have been traced to dry cleaners, and many more are suspected due to past disposal practices of the industry. Landlords and lenders can also be held liable under U.S. laws, and are increasingly reluctant to rent space or make loans to dry cleaners using perc.

Hazardous-waste disposal costs are also rising. Fees to remove perc-contaminated waste from dry cleaning plants have doubled within the last 5 years. Chemical costs are rising as well.

These recent industry trends make the continued use of perc increasingly costly and unattractive to dry cleaners. Dry cleaners who make the switch to water-based methods will not be faced with these expenses and difficulties; on the contrary, they can receive a higher profit and return on investment. And the first to convert or start new businesses using water-based methods will undoubtedly gain an edge in the market as well as contribute to a safer environment and healthier community.