Laundered shop towels may cause exposure to heavy metals: Study

U.S. study shows elevated levels of heavy metals on “clean” towels

Even after commercial laundering, shop towels retain elevated levels of metals, according to a study by Gradient, a U.S. science consulting firm.

The study, Evaluation of Potential Exposure to Metals in Laundered Shop Towels, said these elevated levels could result in worker exposures that exceed agency guidelines.

The towels could even introduce new metals that are not otherwise found in a facility, according to the study.

The study compared the estimated amounts of ingested metals to health-based criteria, including the criteria from the U.S. Environmental Protection Agency and the Agency for Toxic Substances and Disease Registry, a federal public health agency of the U.S. Department of Health and Human Services.

It found the worker using the typical amount of towels per day, would have an average exposure to seven metals (antimony, beryllium, cadmium, cobalt, copper, lead and molybdenum) that may exceed health-based exposure guidelines set by U.S. agencies.

Workers cannot see, smell or feel heavy metal contaminants on laundered shop towels. They are not aware the towels could contain elevated levels of tiny metal particles. Workers who touch towels with their hands may unknowingly transfer these metals from their hands to their mouths, according to Gradient.

Across industries, workers use laundered shop towels for wiping equipment as well as their hands and faces. Industrial launderers then collect the towels from different workplaces, wash them together and send them out again for use by the same or other businesses, said Gradient.

"Manufacturers face an unexpected worker exposure issue: Workers using just one or two shop towels a day may be exposed to elevated levels of heavy metals, compared to health-based exposure guidelines," said Barbara Beck, a principal at Gradient. "Without knowing it, manufacturing workers may be ingesting certain heavy metals at elevated levels from this unexpected source. 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 study was commissioned by Kimberly-Clark Professional. Researchers analyzed data from laundered shop towels submitted by 26 North American companies across various manufacturing industries.

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