EPA Bans Chemical Used Against Pool Algae

Citing evidence that the pesticide simazine causes breast cancer and other health problems in lab animals, the U.S. Environmental Protection Agency yesterday banned simazine-based products used to control algae in swimming pools, hot tubs and whirlpools.

Simazine's primary use is as a weed killer, and that use is still permitted. It is also one of 20 products registered for algae control and accounts for less than 10 percent of that market. It has been licensed since 1971 for use on black and green algae.

Simazine is one of six pesticides that remain on the market despite being designated by the EPA as breast carcinogens in rats and possible human carcinogens. The others are atrazine, cyanazine, express, oryzalin and Terrazole.

All have come under renewed scrutiny by the EPA in light of new evidence that exposure to some pesticides may increase breast-cancer risk if those chemicals are able to mimic the effects of the hormone estrogen.

But the agency said yesterday's action was prompted not by concerns about estrogenicity, but because until recently the EPA had never studied how people could be exposed to the chemical by swimming in simazine-treated water. In the past, the EPA's human-exposure studies for simazine had focused only on its use as a weed killer.

In addition to breast cancer, the EPA said tests on lab animals show that simazine may cause anemia and weight loss.

The EPA yesterday ordered manufacturers to recall unopened containers from dealers, distributors and consumers and urged consumers to dispose of opened containers according to state or local regulations. Open containers should not be dumped into water systems, the agency said.

All but three of the 13 companies registered to produce and sell simazine have voluntarily canceled those registrations, and the EPA plans to take action to force the remaining three companies to take the chemical off the market.

Those three companies are Aladdin Chemical Co. of Greeley, Colo., N. Jonas and Co. Inc. of Bensalem, Pa., and Alden Leeds Inc. of South Kearny, N.J.