The Obama administration last night unveiled the broad outlines of a proposal to overhaul the regulation of thousands of chemicals used in consumer products and the workplace, calling for more testing and greater authority to restrict toxic products.

The plan, which would require legislation, would replace an existing system that is widely seen as ineffective - so much so that it did not allow the government to ban asbestos, a known carcinogen, decades ago.

Chemical manufacturers would have to share more information about the risks of both their existing products and any new creations, with less ability to hide behind claims of trade secrets. The companies would be required to conduct safety tests for certain chemicals, including in some cases tests on lab animals - a level of scrutiny currently not required at all for many new substances.

Public-health advocates welcomed the plan as did representatives for the industry, which in the past has balked at added regulation in favor of voluntary measures. A key reason is that individual states and cities have started to regulate chemicals on their own, leading companies to seek the uniformity of a federal program.

Lisa P. Jackson, administrator of the Environmental Protection Agency, said that a tougher law was "long overdue" and that industry must cover some costs of the new plan. She added that she would pursue regulation of six high-priority chemical groups this fall under the existing law. These include phthalates, which are used to make plastics flexible; bisphenol A, found in the linings of certain food cans and plastics; and perfluorinated compounds, which are used to make nonstick cookware.

Another target is brominated flame retardants, used in textiles and computers. Studies show some may, at high levels of exposure, cause cancer, decrease sperm quality, and affect thyroid function.

"As more and more chemicals are found in our bodies and in the environment, the public is understandably anxious and confused," she said, addressing reporters in a conference call.

New legislation is already in the works; the Senate version is to be sponsored by Frank Lautenberg (D., N.J.).

"America's system for regulating toxic chemicals is broken," Lautenberg said in a prepared statement.

When the Toxic Substances Control Act was passed in 1976, the law grandfathered in 62,000 existing chemicals - meaning that manufacturers could continue to make them without having to demonstrate safety in most cases.

Under the act, the EPA has since approved more than 20,000 additional chemicals - not including those used in pesticides, which are subject to a different, stricter law. In most cases, companies were required only to tell the agency certain basic information about the new chemicals' physical properties and structure, and regulators then evaluated them with computer models.

In practice, just 7,000 of the total 80,000-plus chemicals are widely used, and they are overwhelmingly considered safe, said officials at the American Chemistry Council, the largest industry group, in Arlington, Va.

Yet member companies are willing to have the EPA subject their products to more analysis so long as it is based on a scientific assessment of risk, said council president Calvin Dooley, a former Democratic congressman from California.

"We can create a system that will result in an enhanced level of consumer confidence," Dooley said.

"It's quite a newfound religion," said Richard Denison, senior scientist for the nonprofit Environmental Defense Fund in Washington. "I think they are feeling the effect of a large number of their own customers starting to question the safety of their products."

The existing law requires that, to restrict the use of a chemical, the EPA must determine that any risks are not outweighed by the substance's economic and societal benefits.

The most notorious failing of this law came with asbestos, a substance that has been shown to cause a rare form of lung cancer. The EPA spent a decade documenting the risks, but in 1991, its proposed ban did not withstand a challenge in federal court.

Lynn Goldman, who led the EPA office that regulated chemicals under President Bill Clinton, said the ruling hampered the EPA's ability to protect the public.

In one subsequent case, she tried to ban a chemical called acrylamide, used in sewer grout, that was thought to cause cancer and neurological harm. But she said the agency was unable to prove that banning it was "the least burdensome" way of addressing that risk - the legal standard required by the court.

"It was just an impossible, very unworkable statute," said Goldman, now a professor at the Bloomberg School of Public Health at Johns Hopkins University.

She said the proposed outline for a new law seemed sensible, but warned that it would require more staff, given new challenges such as nanoparticles and the need to study genetic effects.

The chemical-regulation office once employed 600 people. There were 400 people when Goldman was in charge, and now there are 320, she said.

Charles Auer, who headed the office under President George W. Bush, said it was too early to tell how the program would play out, but called it "a nice strong statement of where they want to go."

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