Shop Employees May Be Exposed to Heavy Metals Through Shop Towels - Engine Builder Magazine

Shop Employees May Be Exposed to Heavy Metals Through Shop Towels

Gradient (, a nationally recognized environmental and risk science consulting
firm, recently announced the publication of a study that finds elevated levels
of heavy metals in tested laundered shop towels.

The study, “Evaluation of Potential Exposure to Metals in Laundered
Shop Towels,” builds upon an earlier analysis published in 2003 and
concludes that, even after commercial laundering, the towels studied
retain elevated levels of metals. This could result in worker exposures
that exceed agency guidelines, which are based on various health
effects such as cancer. Additionally, the tested shop towels may
unexpectedly introduce new metals that are not otherwise in a facility.


Exposure to Heavy Metals in Shop Towels Can Exceed Health-Based Limits

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

In addition, estimated metal intakes were compared to the California
Environmental Protection Agency’s (CalEPA) Proposition 65 regulatory
limits for cancer or reproductive effects. The Gradient study finds
that, for the worker using the typical amount of towels per day,
average exposure to seven metals (antimony, beryllium, cadmium, cobalt,
copper, lead, and molybdenum) may exceed health-based exposure
guidelines set by these agencies. For example, based on the
calculations discussed in the 2011 Gradient study, a worker may ingest
up to 3,600 times more lead on a daily basis than recommended by
CalEPA. Excessive metal exposure over time may present a health concern.


Workers Not Aware of Heavy Metal Exposure Issue

Workers cannot see, smell, or feel heavy metal contaminants on
“clean” laundered shop towels, so they are not aware that the towels
could contain elevated levels of tiny metal particles, invisible to the
eye. Workers who touch towels with their hands may unknowingly transfer
these metals from their hands to their mouths. Ingestion of metals from
hand-to-mouth transfer is an important exposure route for metals as
recognized by multiple federal agencies including the U.S. EPA, ATSDR,
the Consumer Product Safety Commission (CPSC), and the Occupational
Safety and Health Administration (OSHA) .


The National Association of Manufacturers estimates that nearly 12
million Americans, or nine percent of workers, are employed in
manufacturing. Across industries — from equipment manufacturing and
printing, to aviation and automotive work, to food and beverage
packaging and medical device manufacturing — 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.  


“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, Ph.D., DABT, principal at Gradient, who has testified before the U.S. Congress on lead toxicology issues.

“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.”


Commissioned by Kimberly-Clark Professional, Gradient researchers
analyzed data from laundered shop towels submitted by 26 North American
companies across various manufacturing industries. The towels were
submitted to an independent lab for testing. Gradient found
significantly higher levels of contamination than in the similarly
designed 2003 study <> .


• More heavy metals exceed health-based exposure criteria:
A worker using a typical number of laundered shop towels a day (12) may
be exposed to levels of antimony, beryllium, cadmium, cobalt, copper,
lead, and molybdenum that are higher than health-based guidelines set
by regulatory agencies.

• Tested towels are dirtier: The
concentrations of six metals—aluminum, barium, calcium, copper,
magnesium, and sodium—were found to be significantly higher than towels
tested in the original 2003 Gradient study.

• More metals detected more often: A wide
variety of heavy metals were commonly found on the shop towels tested.
Of the 29 metals studied, 26 were found on more than 90 percent of the
towels tested.

It is unlikely that metals found in the tested towels could come from a
single industry source. For instance, beryllium is not commonly used in
manufacturing sites, but was present in a number of the towels.
Launderers combine towels from multiple industries before washing,
which may contribute to this finding.


The new report, “Evaluation of Potential Exposure to Metals in
Laundered Shop Towels,” is available at

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