Some water coolers in schools, offices and other public places release very high concentrations of lead with each drink, contributing to unsafe levels of the hazardous metal in much of the nation's drinking water supply, according to new findings of the Environmental Protection Agency.

Tests of water from refrigerated fountains at an unidentified federal agency revealed lead concentrations as high as 40 times the recommended EPA standard. The average lead level from five different brands of coolers exceeded safety standards by threefold to sixfold, depending on the length of time the water was allowed to run, the EPA reported.

Deposits of the metal apparently came from lead coating water tanks or lead solder connecting coils. Previously, high lead levels have been traced to corrosion in the plumbing systems of buildings, but samples from the coolers carried more lead than tap water, the EPA reported.

Although the coolers tested earlier this year probably are typical of public fountains everywhere, it is unclear how widespread the problem is, said Jeanne Briskin, of the EPA's Office of Drinking Water. Not all of the agency's coolers leaked excessive concentrations of lead, and industry officials said that only older models contain the metal.

But Paul Mushak, senior author of a Public Health Service report on lead, said that coolers may be an "insidious" source of the metal, especially in schools, where lead can accumulate in the fountains during long lapses in use.

And Rep. Henry A. Waxman (D-Calif.), chairman of the House Energy and Commerce health and environment subcommittee, who will hold a hearing on lead in drinking water Thursday, said he plans to urge manufacturers to stop sales of lead-leaking coolers and state governments to remove them from schools and public buildings.

"This is a problem that concerns the health and intelligence of our nation's children," he said.

Once considered a health problem restricted to lead refinery workers and ghetto children who eat chips of peeling paint, lead has emerged in recent years as one of the most dangerous and pervasive pollutants.

Even low levels of the metal absorbed in the blood have been linked to diminished physical and mental growth in children, hypertension in middle-aged men and pregnancy complications for women.

Last year, the EPA estimated that one of every five Americans consumes unsafe levels of lead in residential drinking water. This excess alone was said to be responsible annually for lower intelligence quotient scores for 240,000 children, hypertension for 130,000 white males and pregnancy complications for 680,000 women.

Those findings and an EPA proposal to tighten the drinking water standard from 50 parts per billion (ppb) to 20 ppb prompted a federal agency to sample its water for lead, both at the tap and the cooler, according to Briskin.

Forty samples drawn immediately from the cooler averaged 125 ppb of lead and reached a high of 570 ppb. Since such first-flush samples generally register more lead because the metal accumulates in pipes, a second batch of 119 samples was taken after running the fountain from one to two minutes. The average was 64 ppb, and the highest level was 830 ppb. The lowest level for both draws was 5 ppb.

Briskin said all of the fountains releasing high levels of lead have been replaced by the agency, which she declined to identify.

The EPA memorandum identified high lead levels in coolers manufactured by five firms: Halsey Taylor Co., Elkay Manufacturing Co., General Electric, Sunroc Corp. and Cordley.