The moment Mark Spiro walked into G&K Services, an industrial laundry in Waterbury, the steamy air stung his eyes and made his head ache. The place reeked of chemical solvents: methyl ethyl ketone, xylene, toluene - the sickly sweet scents of spray paint, permanent markers and model glue.

On that day in 2007, Spiro, an air pollution control engineer with Connecticut's Department of Energy and Environmental Protection, discovered high levels of volatile organic compounds (VOCs) pouring from G&K's roof stacks, the result of laundering shop and print towels contaminated with toxic solvents, state records indicate. The state eventually sued G&K, won a $1.8 million settlement and stopped the facility from laundering shop and print towels in Connecticut.

Laundering shop and print towels, which are cloths used to wipe oil, solvent and other chemicals off machinery, can fuel the release of VOCs above federal limits. The use and processing of shop towels is largely under regulated, despite its potential to emit toxic substances into the air. When the DEEP uncovered the chemical release violations at G&K, it alerted the U.S. Environmental Protection Agency, which launched its own investigation into all industrial laundries in New England. "Based on EPA documents, this appears to be an issue that has been missed for a long time," said Steven Rapp, chief of the Air Technical Unit, EPA Region 1. "It's a complete sleeper."

So far, the EPA's ongoing probe has identified and inspected 17 industrial laundries in New England, including UniFirst in Stratford and AmeriPride in Hartford, that process shop or print towels. The EPA has brought action against two other facilities, in Manchester, N.H., and New Bedford, Mass., for violations of the Clean Air Act, and has ordered testing of others.

The state and federal investigations have also exposed a potentially bigger problem: the spotty oversight of chemical-laden shop towels as they travel from factory floor to washing machine. The EPA and the laundry industry disagree on who bears liability for VOC emissions along this supply chain, with the EPA targeting laundries and the laundries pointing at customers.

This poorly regulated process can lead to a mix of incompatible chemicals at the laundry, creating additional risks for human health, the environment and fire, according to state and federal officials.

This story was reported under a partnership with the Connecticut Health I-Team (www.c-hit.org).

"If you don't know what's in there it could be hazardous," said EPA's Rapp. "There have been explosions at these types of facilities. We've heard reports of fires in the washing machine when the washer is going. What are you ignoring when the water is on fire?"

From October 2006 to October 2007, G&K in Waterbury produced an estimated 180 tons of VOCs, 130 tons over the legal limit. This made G&K the largest emitter of VOCs in the state, more akin to a hazardous waste processing facility than a laundry.

"I've been here 25 years. I've been in enforcement my whole career. This is by far the worst case I've ever seen," said Robert Girard, assistant director of the Air Enforcement Program at CT DEEP.

"It was a total surprise to us that an industrial laundry would be a source of VOCs," said Gary Ginsberg, senior toxicologist at the Connecticut Department of Public Health.

VOCs are chemicals that evaporate quickly, and many common products, like paint thinner, contain them. VOCs range from innocuous to toxic, but because they evaporate rapidly people are likely to inhale them.

When Ginsberg analyzed the emissions from G&K, he found that they posed a potential threat to public health, especially for vulnerable groups like children and the elderly. Many organic solvents irritate the skin and eyes, and can cause nausea, dizziness and headaches. Long-term exposure can damage a person's kidneys, liver and respiratory system.

Most troubling at G&K were high concentrations of two particular chemicals: hexachlorobutadiene, a carcinogen that Ginsberg describes as a "very active toxin," and isophorone diisocyanate, a highly irritating chemical that causes lung and eye damage.

Waterbury resident Marie DellAnno, who lives across the street from G&K and alerted DEEP to the odor, said the smell - like lighter fluid, "but a thousand times worse" - made her dizzy and nauseous. "A smell like that, it comes after you and grabs you," she said.