EPA says perchlorate may cause more harm

Thursday, Jan. 17, 2002 | 9:58 a.m.

Perchlorate, a rocket fuel booster found in Southern Nevada's drinking water, causes more harm to human health than scientists believed, a draft Environmental Protection Agency report says.

The EPA is preparing a risk assessment, the first step leading to a national limit of the chemical in drinking water. The process could take 10 years, EPA officials have said.

Scientists knew in the 1950s that perchlorate could cause thyroid cancer or slow growth in children. The chemical has been made by two companies in Henderson since 1952. Kerr-McGee Chemical Corp. is working with Nevada environmental officials to clean the chemical, a salt, out of local drinking water.

Perchlorate has been found in the Las Vegas Wash and Lake Mead. The highest level of the chemical recorded in local drinking water was 26 parts per billion in December 2000.

The Oakland, Calif., organization Environmental Working Group is suggesting a limit of 3.2 parts per billion, Bill Walker, an analyst for the group, said. That's equal to three drops of perchlorate in an Olympic-size swimming pool. The group analyzed the EPA's data in the draft report, Walker said.

The Environmental Working Group withdrew its analysis from public access last week after a request from EPA to do so.

Southern Nevada Water Authority officials had not seen the EPA's report or the environmental group's study, spokesman J.C. Davis said. The water authority found perchlorate at 14 parts per billion in December, he said.

Kerr-McGee Chemical Corp. has said it will begin this year removing most of the perchlorate from the Las Vegas Wash leading to Lake Mead, Davis said.

EPA spokeswoman Lisa Fasano said that the public may comment on the draft report until Feb. 11. It can be found at www.epa.gov.