Once a week, a batch of freshly laundered red towels, sealed in plastic, arrives at the Atlas Garage on the Upper West Side of Manhattan, while 100 or so soiled rags begin their journey back to a commercial washing facility.
Riaz Khan, 33, has spent the last 11 years caring for cars at this neighborhood shop -- checking oil, changing tires and performing other skills of his trade. While he has always been conscious of the gasoline and other fumes he breathes daily, it never occurred to him that the 10 or so "clean" towels he goes through in a typical eight-hour shift might be exposing him to toxic heavy metals, let alone at concentrations of up to 7,700 times current EPA limits.
"They're just like disposable towels," he said as his cousin, Fayaz Khan, 32, checked out a customer's car, wiping down a dipstick with a red rag. "We use them and toss them in the bin. And they are washed really well."
The towels did look, smell and feel quite clean. But could they actually harbor hidden hazards for the some 12 million automotive, printing and other manufacturing and industrial workers in the U.S.?
Makers of disposable shop towels and providers of the reusable variety have long been battling for the hearts and minds of the nation's mechanics and machine-shop owners, whose dirty jobs expose them to a variety of potentially unhealthy metals and oils. A new study sponsored by Kimberly-Clark Professional, one of the nation's largest makers of disposable towels, represents the latest salvo, suggesting that workers using laundered towels are in fact exposing themselves to high levels of lead, cadmium and other heavy metals.
Not surprisingly, providers of laundered towels -- and even some independent toxicology experts -- viewed those claims with skepticism.
The authors of the new report, published on Monday, suggest exposure to the metals, oil and grease that don't get removed in the wash can occur both directly and indirectly: a worker may graze their lips with a towel while wiping off sweat, or touch their fingers to their mouth after using a towel to remove grime from a hand or tool. (The average person subconsciously touches his or her face an estimated 16 times an hour.)
Over time, they say, the toxins can accumulate in the body, potentially leading to cancer or other damage to tissues and organs including the brain, bones and blood.
"This is an entirely unexpected and unnecessary source of metal exposure in the workplace," said Kim Dennis MacDougall, a research scientist at Kimberly-Clark. She compared the apparent lack of awareness to that of smokers in the 1940's and 1950's, who had "no realistic association between cigarettes and illness."
After surveying 26 U.S. and Canadian companies and analyzing data from a randomly selected sample of 26 of their laundered towels, researchers at Gradient, an independent environmental consulting firm in Cambridge, Mass., found that the average worker who uses 12 towels a day may be exposed to seven metals -- antimony, beryllium, cadmium, cobalt, copper, lead, and molybdenum -- at levels that exceed health-based exposure guidelines.
Furthermore, of the 29 metals for which the researchers tested, 26 were found on more than 90 percent of the towels.
Lead exposure, which has been linked to nervous system damage, may be of particular concern. Gradient's analysis found that the typical 12-towel-a-day worker may ingest up to 3,600 times more lead than is recommended by the EPA. Those who use 26 towels per day, meanwhile, may ingest up to 7,700 times the limit. Even using just one towel daily would expose users to lead levels that exceed the safety threshold, they estimated.
The research is an extension of a 2003 study, which MacDougall noted was prompted by indications from workers that their laundered shop towels often smelled of solvents and oil.
Barbara Beck, principal at Gradient and lead author of the study, noted that her team remains the only group of researchers to have delved into this issue. She also acknowledged that they have faced limitations, including a lack of established rates at which contaminants can be transferred from a shop towel to a hand or mouth. They improvised with estimates gleaned from studies of chemicals transferred from other soft surfaces such as carpet.
Working conditions such as air quality have generally improved since the 1970s, said Robert Herrick, a senior lecturer on industrial hygiene at the Harvard School of Public Health in Boston. Yet Herrick, who was not involved in the study, says the issue of occupational exposure via shop towels has yet to move onto people's radars.
"This, too, needs to be investigated and followed up more thoroughly," said Herrick. "There's no reason for a worker to think that there's any contamination."
Like the Khan cousins, Aaron, a car mechanic at Manhattan Jeep Eagle, has assumed that the freshly washed towels he uses are perfectly clean.
"We send them out pink and they come back red," said Aaron, who preferred not to provide his last name. He pulled out a pinkish-red rag covered in dark smudges. "They disinfect the heck out of 'em," he added.
Industrial workers that don't use toxic materials themselves may be particularly unaware of the potential risk of contamination. Shop towels from a food or beverage manufacturer, for example, could have been laundered in the same facility as those soiled by automotive and heavy equipment companies.
"It all goes into the same mix," Herrick noted.
What's more, after growing up in a family of industrial workers, Herrick learned that potentially toxic hazards could also be brought home. Shop towels can be handy for do-it-yourself projects around the house. He even recalled using them as a kid to clean the grease off the spokes of his bike.
Yet Kevin D. Schwalb, director of government relations for the Textile Rental Services Association in Alexandria, Va., questions the presence of any risks -- whether at the shop or home. In fact, he calls the research "profit-driven and baseless," pointing to the relatively small size of the study and the fact that it was not published in a peer-reviewed journal.
"Hundreds of millions of shop towels have been used by millions of employees for more than 100 years and we have never heard of any health issues related to their use," Schwalb said in an email.
"The industrial laundering processes and formulas used to clean reusable towels (chemicals, water temperature, agitation) are engineered specifically to maximize cleanliness and minimize environmental impact," he said. "Any materials including residual metals still on towels after laundering would have to be significantly bound to the fibers, making any transfer from towel to hands or mouth virtually impossible."
Alfred Bernard, a toxicology expert at Catholic University of Louvain, in Belgium, agreed, questioning the "astonishingly elevated metal concentrations" found in the study and urging that the "data be interpreted cautiously."
Robert L. Redding, Jr., Washington, D.C. representative of the Automotive Service Association, noted in an email that most auto shops now use reusable towels and that trend is unlikely to change until there is a more "targeted study of wipes in the automotive shop environment."
Further supporting the use and re-use of laundered towels is what Herrick calls "vigorous promotion" of the use of reusable towels among some groups, such as the center for Environmental Compliance for Automotive Recyclers. The sector-specific Web-based center advises people who generate contaminated material to use laundered towels, and thereby avoid responsibility they would otherwise confront if disposing of used towels. (The U.S. Environmental Protection Agency (EPA) currently regulates disposable and reusable shop towels separately.)
"Why take a chance of being on the hook for generating hazardous waste when you use something disposable?" he said. "You can just get around regulation by using things laundered. I don't think this is on the screen for anyone in the regulatory community."
Catherine C. Milbourn, senior press officer at the EPA, noted in an email that the agency is "currently working to finalize a rule that addresses the safe handling and disposal of used industrial wipes containing spent solvents, as well as the management of used wipes that will be laundered and wipes that will be disposed."
For now, MacDougall recommends that companies worried about the potential risks of laundered towels -- particularly companies that aren't "dirty," such as those that manufacture food -- choose a launderer that doesn't recycle rags across multiple industries.
"They could also change their practice to minimize contacts with towels, such as adopting hand washing and decontamination protocols before going on break or before going home," she said.
Jeff Weidenhamer, chair of the department of chemistry, geology and physics at Ashland University, in Ohio, added some more possibilities. Weidenhamer, who was not involved in the study, suggested changing laundering methods and choosing towels made of materials that would be less likely to trap particles, such as ones with flat surfaces rather than loops like a bath towel.
Both New York City businesses already have some precautions in place, including the use of a mix of reusable towels for messy work, like wiping down a wrench or screwdriver, and disposable ones for drying hands.
The bin for soiled rags at Aaron's shop also bears a warning: "Do not wipe face with shop towels."