More than one in six Americans is at risk of being seriously harmed or killed by toxic chemical releases, plant fires or industrial explosions, two environmental groups contend.

A study issued Tuesday by the National Environmental Law Center and the U.S. Public Interest Research Group ranks the states and localities considered most vulnerable to chemical disasters."More than 44 million Americans live within range of a deadly toxic cloud that could result from a chemical accident at a facility located in their ZIP code," said Hillel Gray, the law center's policy director and co-author of the report.

Texas, California and Ohio lead the nation in terms of worst-case chemical accident potential, the study said, followed by Illinois and Louisiana. Rounding out the top 10 are Pennsylvania, Michigan, New York, Indiana and Georgia.

Cities with the highest potential of worst-case disaster are Houston; Chicago; Baton Rouge, La.; St. Louis; Baltimore; Los Angeles; and Memphis.

Utah was ranked 35th in the nation for danger chemical accidents, said Warren Alfred, U.S. PIRG state campaign director.

He said that means one in six Utahans also are directly in danger of being exposed to toxic chemicals.

At a late-morning news conference in Salt Lake City, Alfred listed four Utah companies among 400 nationally that he said posed the potential for the greatest danger - Magnesium Corp. of America, which has a plant near the Great

Salt Lake in Rowley; Westinghouse's Ogden operation; Westernelectro, in Cedar City; and Thatcher Chemical in Salt Lake City.

All of those companies either manufacture or store chlorine, except for Westernelectro, which houses ammonia.

"This report should be a call to action for business leaders and citizens in the state of Utah," said U.S. PIRG spokesman Eric Wilden.

The rankings were based on the Environmental Protection Agency's Toxic Release Inventory data. The law center then calculated for nearly 10,000 manufacturing companies the worst-case scenarios of deaths or serious injuries that could result in the event of disaster.

A spokesman for the Chemical Manufacturers Association, which represents some of the nation's largest chemical companies, said the study doesn't consider industry's efforts to improve safety.

'The (Toxic Release Inventory) basically just measures how much you are putting out into the environment," said CMA spokesman Matthew Weinstock. "It doesn't measure what you are doing inside the fence line to safeguard against an actual release or anything."

Added Weinstock, "The CMA member companies take very seriously their commitment to safety and health of their communities and the neighborhoods, and I think have a pretty good record of being able to safeguard against accidental releases and spills and so forth."

The environmental groups recommended that industry and government make public their worst-case accident estimates.

They also took aim at proposals on Capitol Hill that would weaken reporting requirements by industry.

The House voted this month to restrict the ability of the Environmental Protection Agency to enforce a decade-old "right-to-know" law that requires some 23,000 manufacturing facilities to issue annual Toxic Release Inventory reports on emissions of 651 chemicals tracked by the government.