Dry cleaning businesses would have to stop using perchloroethylene, known as perc, by the year 2020. The South Coast Air Quality Management District also approved $2 million in grants to help dry cleaners switch to other chemicals.
"I think it needs not only to be reduced but to be phased out altogether," said board member Roy Wilson, who introduced the measure.
A study done by the board staff showed about 50 percent of the perc used by dry cleaners finds its way into the air. Previous studies put that number at only 15 percent.
The board said the chemical is among six major airborne toxic substances in the region.
Scientists estimate the risk posed by long-term exposure to perc is between 20 and 140 in 1 million. Studies have linked the compound to cancers of the lung, cervix, esophagus and bladder in dry cleaning workers.
Since 1994, regulations have reduced by 80 percent the amount of the chemical released. The board has pushed alternative technologies, but dry cleaners said they are unproven and more costly.