The debate continues over the hygiene of laundered shop towels.

A new study, “Evaluation of Potential Exposure to Metals in Laundered Shop Towels,” published by Gradient, updates findings from a 2003 analysis and still shows that towels retain elevated levels of heavy metals, even after commercial laundering.

According to the study, a worker using 12 laundered shop towels a day will be exposed to seven metals that exceed health-based exposure guidelines set by the U.S. Environmental Protection Agency, the Agency for Toxic Substances and Disease Registry and the California Environmental Protection Agency’s (CalEPA) Proposition 65 regulatory limits for cancer or reproductive products. The concern is that workers who touch the towels with their hands may inadvertently transfer the metals to their mouths by touching their faces. As a result, industrial workers may ingest up to 3,600 times more lead on a daily basis than recommended by CalEPA, states the study.

“Without knowing it, manufacturing workers may be ingesting certain heavy metals at elevated levels from this unexpected source,” says Barbara Beck, Ph.D., DABT, principal at Gradient. “For some of these metals, the amounts ingested may be greater than allowed in drinking water on a daily basis. Because towels are used and then laundered multiple times and are often delivered to different companies each time, workers may even be exposed to metals that do not otherwise exist in their work environment.”

The Textile Rental Services Association of America (TRSA), however, expresses doubts because the study provides no evidence that residual materials have ever been transferred to a person or ingested.

“In regards to employee safety, 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,” says Kevin Schwalb, director, government affairs for TRSA.

According to Schwalb, the laundering process for reusable towels is engineered specifically to maximize cleanliness.

“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,” he says.

Jan/san distributors sell disposable wipers to industrial facilities, but compete for these same accounts against uniform companies who rent laundered shop towels.