When it comes to dry cleaning, nothing else gets stains out like a chemical called perchloroethylene, or "perc," for short.

"I can't say I've seen anything better," said Mike Hill, plant manager for the Caskey Cleaning Co. at 47 W. Gates St. on the South Side.

Maybe, but for decades, officials at the U.S. Environmental Protection Agency have been studying the chemical as a cancer threat. After years of research, the EPA has proposed changing that threat level to people from "possible" to "likely."

Ohio businesses released an estimated 313,000 pounds of perc into the air in 2008, but industry groups continue to argue that even a "likely" cancer connection hasn't been proved.

"I've been working around it now for over 14 years, and my father has been working around it for over 30 years," Hill said. "We haven't seen any ill effects."

EPA officials and environmental advocates point to perc as an example of an even-bigger problem - a federal law that they say keeps the government from protecting people from dangerous chemicals.

The Toxic Substances Control Act, passed in 1976, was intended to give the U.S. EPA authority to restrict the use of chemicals or other substances if it determines they are hazardous.

But the law restricts the EPA's ability to enforce limits on chemicals in use before the law was passed. Perc dates back to the 1930s.

The law also restricts the agency's ability to act on new, outside research that links chemicals to human health problems. As a result, the agency has ordered tests on 200 of 84,000 chemicals used in business services and products.

Since 1976, the EPA has restricted the use of asbestos and lead-based paint and banned the use of only one class of chemicals, PCBs.

Lisa Jackson, the U.S. EPA administrator, called the law "toothless" during an appearance Thursday in Columbus. She said she's pushing Congress to pass a law that gives the EPA more authority to more quickly review chemicals.

"Americans are calling out for more safety in the products that they use," Jackson said. "I believe there is a real opportunity for a bipartisan legislative solution."

Richard Wiles, senior vice president for policy at the Washington-based Environmental Working Group, said a bill could be drafted within weeks.

Wiles said any new law should be similar to those that govern pesticides, which require studies that show how much of a chemical ends up in the food we eat.

The U.S. EPA has had similar problems restricting the use of other chemicals, including bisphenol A, a compound used in clear plastics and food cans linked to reproductive and nervous-system problems and cancers in lab animals.

Then there is perfluoroctanoic acid, or C8, a chemical DuPont uses to help make Teflon. Studies indicate that nine of every 10 people have at least trace amounts of it in their blood. It has been labeled a "likely carcinogen."

Wiles said companies have a responsibility to protect customers and others.

"If they want to sell a chemical, they have a duty to show what those exposures are," Wiles said.

It's not clear how industry groups will respond. Jack Pounds, president of the Ohio Chemistry Technology Council, said businesses need clear and understandable rules that they and regulators would have to follow.

Alan Spielvogel, director of technical services for the National Cleaning Association, said accuracy in health studies is more important that speed.

Where perc is concerned, "There needs to be more study done on this," he said.

The U.S. EPA is proposing to limit perc between 6 parts per billion to 50 parts per billion in air.

Spielvogel said such restrictions could force cleaners to use more expensive chemicals or costly filters. Hill said many dry cleaners already use "closed" systems that keep perc out of the air by cycling the dirty solvent through filters so it can be reused.

A 1997 Centers for Disease Control and Prevention study found these closed-system cleaners release much higher amounts of the chemical - an average 16.9 parts per million.

It's not clear when the U.S. EPA will make a decision on how to label the chemical.

"EPA will work as expeditiously as possible," said spokeswoman Latisha Petteway.

Miracle cleaner or dangerous substance?

Perchloroethylene, or "perc," is a chemical used in dry cleaning. It evaporates easily and gives off a sharp, sweet odor.

What it does - The chemical belongs to a family of industrial solvents. It also is an ingredient in printing inks, glues, polishes, lubricants, rug and upholstery cleaners, and stain, spot and rust removers.

History - Perc has been used since the 1930s.

In the environment - Perc has been found in groundwater in more than 770 of 1,437 hazardous-waste sites on the U.S. Environmental Protection Agency's National Priorities List.

Health effects - High concentrations can cause dizziness, headache, sleepiness, confusion, nausea, difficulty in speaking and walking, unconsciousness, and death.

Cancer risk - The chemical has been linked to liver tumors in mice and kidney tumors in male rats. The U.S. EPA has proposed declaring it a "likely" human carcinogen, which would require tighter restrictions on its use.

Source: U.S. EPA, Centers for Disease Control and Prevention