The Bush administration's controversial proposal for regulating mercury emissions from power plants would allow continued, unregulated releases of arsenic, lead and 60 other toxic material that could harm public health, according to a new study by the Clean Air Council.

That major policy change would be particularly bad for the health of Pennsylvania residents, the study says, because the state's 27 power plants emit more arsenic into the air than those in any other state, more lead and chromium than those in all but two other states and significant amounts of the other airborne toxics.

While recent reports by other environmental groups on the U.S. Environmental Protection Agency's proposed mercury rule have focused solely on mercury emissions, the study released yesterday says the rule's provisions for unregulated releases of other toxics also could be harmful to public health.

"It is now clear that mercury is just the tip of the iceberg," said Arthur Stamoulis, policy analyst for the Clean Air Council, a statewide environmental group.

"Power plants in this state are emitting tens of thousands of tons of arsenic, lead and other toxic air pollution and the Bush plan will keep these substances completely unregulated."

The administration's proposed mercury controls feature a "cap and trade" system that would allow utility companies to reduce mercury emissions from some power plants but not others. Its goal is to reduce mercury emissions by 14 million tons, or 30 percent, by 2010 and 70 percent by 2018.

That is far short of the 90 percent reduction in mercury emissions by 2008 proposed by the Clinton administration and endorsed by Bush's first EPA administrator, Christine Todd Whitman.

The Clean Air Council study said the proposed mercury rule would change the classification of electric utilities as a major source of Hazardous Air Pollutants, or "HAPs," a legal maneuver necessary because the federal Clean Air Act prohibits the trading of those toxics.

Such a major policy change would have the effect of allowing power plants to avoid any controls on all of the more than 60 HAPs the EPA has identified in power plant emissions.

It also would run counter to a recent EPA determination to regulate many of these same substances ---- including arsenic, cadmium and chromium ---- as hazardous pollutants when emitted by industrial, commercial and institutional boilers.

Pennsylvania is one of 11 states that have filed critical comments on the mercury rule-making, telling the EPA that the Clean Air Act requires the regulation of all hazardous air pollutants and "does not authorize EPA to pick and choose which HAPs it will regulate."

In response to yesterday's report, the EPA cited a 1998 EPA report to Congress that concluded that mercury poses the greatest threat to human health and that regulation of other HAPs was not appropriate.

The EPA response says that reductions in many of theunregulated HAPs will "occur in conjunction with reductions of conventional pollutants."

In 2002, the most recent year for which EPA data is available, Pennsylvania power plants emitted 18,826 pounds of arsenic, a known human carcinogen; 14,146 pounds of lead, which can cause childhood learning disabilities at low doses; 41,750 pounds of chromium, which can cause respiratory tract damage. Several of the coal-fired power plants in the state are among the highest emitters of toxics in the nation.

Nationwide in 2002, power plants emitted more than 120,000 pounds of arsenic, 250,000 pounds of lead and lead compounds, and 300,000 pounds of chromium and chromium compounds.

By comparison, coal- and oil-burning utilities emit 96,000 pounds of mercury annually, about 40 percent of the nation's mercury pollution and the largest single source. The 1990 amendments to the Clean Air Act exempted utilities from mercury controls, but subsequent EPA scientific studies led to a decision in December 2000 to regulate the metal as a toxic pollutant.