The annual federal Toxic Release Inventory was started 15 years ago to let people know about the amounts and kinds of toxic pollutants emitted into the air, water and soil of their communities.

But an analysis of the inventory released yesterday by environmental groups in Texas, Pennsylvania, Louisiana, Kentucky and Washington, D.C., says the TRI significantly underestimates the amount of toxic air releases and that the U.S. Environmental Protection Agency has known for years that the information is inaccurate.

In response, the EPA rushed to release a summary of its 2002 TRI report yesterday afternoon that shows the total air, water and land releases increased by 5 percent -- only the second emissions increase in the inventory's 15 years of reporting.

According to the study by the Washington, D.C.-based Environmental Integrity Project and the Galveston Houston Association for Smog Prevention, the actual emissions -- including human carcinogens benzene and butadiene -- from refineries and chemical plants are four to five times the amounts that those facilities have self-reported to the TRI program.

The analysis says underreporting of toxic releases nationwide totals at least 330 million pounds per year. At least 5 million pounds of unreported emissions occur in Pennsylvania.

"The public is being exposed to far more toxic air pollution than the EPA acknowledges for the record," said Kelly Haragan, Environmental Integrity Project counsel. "It's time that the EPA and the states deal with the problem of inaccurate and flawed reporting of toxic releases."

She said the systematic underreporting occurs because most air pollution is estimated based on models and formulas that the EPA knows are inaccurate.

In 2001, the U.S. General Accounting Office called on the EPA to improve its oversight of emissions reporting and calculated that only 4 percent of all emissions reports sent to the TRI by industries, refineries and utilities were made using direct monitoring or testing.

Despite that recommendation, the EPA this year adopted weaker new rules that changed air emission reporting mandates, requiring facilities to monitor actual emissions only more than once every five years.

"It is a guessing game to figure out which facilities are reporting accurately," said Rachel Filippini, director of the Group Against Smog and Pollution in Allegheny County. "The fact that EPA accepts estimates, rather than requiring the actual monitoring of the emissions of these toxic chemicals that affect public health, is astounding."

Haragan said studies done by the Texas Commission on Environmental Quality and other independent groups in Houston show that actual emissions releases were two to 14 times the amounts reported in TRI reports filed by chemical plants and refineries in the Houston area.

The analysis published yesterday concludes that at least 16 percent of toxic air emissions from all sources nationwide "have been kept off the books."

But EPA spokeswoman Kim Nelson said the agency "has no evidence there are significant trends in underreported emissions" and has taken no enforcement actions based on underreported releases.

"The law says the facilities must submit the best available information," Nelson said. "If there is monitoring information, they must submit that, but the law doesn't require monitoring of all chemical releases."

Nelson said the TRI data for 2002 -- collected on releases of more than 650 chemicals at 25,000 facilities -- show that lead releases increased by 3.2 percent, mercury increased by 10 percent and dioxin decreased by 5 percent. The only other year when overall pollution emissions showed an increase was 1996-97, when they went up 2.7 percent.

Nelson laid the blame for most of the pollution release increase on a smelter shutdown in Arizona.

Philip Clapp, president of the National Environmental Trust, said the emissions increases documented in the TRI are a reflection of weakened regulation and enforcement by the Bush administration.

The EPA yesterday did not release TRI data for 2002 for specific states but plans to do so today. In 2001, Pennsylvania industries, utilities, refineries and chemical plants released approximately 94.7 million pounds of pollutants into the air, the fifth most in the nation.