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Q&A: Heavy Metal Safety

A recent study released by Gradient found that towels are often contaminated with heavy metal residues from other industries that survived the cleaning process.

A recent study released by environmental consulting firm Gradient found that towels routinely used by food manufacturers are often contaminated with heavy metal residues from other industries that survived the cleaning process. Food Manufacturing spoke with Kim Dennis of Kimberly-Clark Professional about the health risks of this issue, as well as the steps food processors can take to enhance the safety of their clothing and safety apparel.

Q: What are the most important safety issues when it comes to plant clothing and safety apparel in the food industry?

A: The Kimberly-Clark Professional Safety Survey, released on July 27, 2011, found a high rate of non-compliance with personal protective equipment (PPE) protocols, which is an important issue that needs to continually be addressed.

Among safety professional respondents from food processing and other industries, 89 percent said they observed workers not wearing safety equipment when they should have been. The protocols with least compliance included wearing eye protection, hearing protection, respiratory protection/masks, protective apparel, gloves and head protection, respectively. To address these issues, many safety professionals are planning enhanced education training programs or increased monitoring of employees. This proactive approach is encouraging.

The good news is the survey indicates growing awareness of potential heavy metal exposure from reusable shop towels. For example, 81 percent were aware that industrial workers could transfer dangerous metals to their hands and clothes from reusable shop towels. Raising awareness continues to be important, however. While 44 percent of respondents said they knew heavy metals could make their way into a facility’s operations via laundered rental shop towels from other companies’ manufacturing processes, 36 percent did not.

Q: Which types of items in a food plant pose the greatest health risk?

A: Introduction of foreign materials into any food processing facility is a serious concern. Most food plants have extensive documentation requirements for traceability and sanitization tracking the ingredients and origin of any materials being introduced to their product.

Whether or not it is the greatest health risk in a food plant, heavy metals that could be introduced into the work environment through shop towels is one of the least understood and monitored risks there. Because industries that must be clean, such as food plants, typically have equipment with moving parts that must be maintained in some fashion, a maintenance area is located on premises to support the repair and keeping of equipment. At a minimum, shop towels could be found in this area of the facility, if not found on or around the production floor. Surprisingly, metal residues, which can present a human exposure health hazard, are often found on laundered shop towels. Safety professionals are not often aware of this unexpected source of metals being introduced to their work environment via use of “clean” shop towels. In the case of food manufacturing, this source of metals may present a far-reaching hazard of exposure to heavy metals requiring further exploration to ensure the safety of the process as well.

Q: What were the levels of heavy metal exposure from these towels, and what dangers do such levels pose?

A: Commissioned by Kimberly-Clark Professional and released on July 11, 2011, Gradient researchers analyzed data from laundered shop towels of North American companies across many industries, including food processing plants. The study establishes a model of exposure based on the actual use practices of workers who handle “clean” shop towels barehanded and touch their face and mouth where ingestion can occur. The predicted metal intake was then compared to applicable exposure health-based guidance, such as CalEPA Proposition 65, U.S. Environmental Protection Agency (EPA) Oral RfD and the Agency for Toxic Substances and Disease Registry (ATSDR).

Even after commercial laundering, the shop towels studied retain elevated levels of metals. 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 California Environmental Protection Agency (CalEPA). For the person using the typical amount of towels per day, exceeding CalEPA Proposition 65 limits, or U.S. EPA and ATSDR health-based criteria, may occur for antimony, beryllium, cadmium, copper, molybdenum and lead. The number of compounds with health-based criteria exceedances is higher in the 2011 evaluation than in the 2003 assessment, due to a number of factors including higher detected concentrations and greater towel usage.

Q: What is the original source of these heavy metals in food manufacturing environments?

A: Food plants routinely rent reusable shop towels from commercial launderers. The washing and reuse of shop towels by commercial launders can occur many times before the shop towels are retired. The 2011 Gradient study established that 26 of the 29 metals tested appeared at a frequency of 90 percent within the sample set. However, very few if any industries use 26 different metals in their processes. This suggests co-mingling either throughout the laundering process or through sharing of towels between companies. Further study could help identify the source of heavy metal contamination, which may occur in the laundering process.

Q: What can manufacturers do to prevent cross contamination of heavy metals from shop towels to workers?

A: Shop towels are commonly used for everything from process wiping to personal wiping, like wiping hands, faces and necks. Metals on the shop towels can get onto hands, then be inadvertently transferred to the mouth and swallowed. Because these towels are used daily by employees, and workers are completely unaware of this potential hazard, the employer has a responsibility to protect their staff from this unnecessary risk. Manufacturers should have workers follow these guidelines:

  1. Do not wipe your hands, face or mouth with laundered shop towels. To avoid skin contact, gloves are recommended.
  2. Always thoroughly wash your hands with soap and water, and dry with a clean paper towel before eating or touching your eyes or mouth.
  3. Wash your hands and face before leaving work to avoid the potential of taking heavy metals home to your family.
  4. Do not tuck laundered shop towels into uniforms or clothing. Avoid wearing uniforms home.
  5. Do not take home laundered shop towels or wash them along with your clothes at home.

Using laundered shop towels is a source of potential worker exposure that can be easily avoided by incorporating the above protective and washing habits to minimize the likelihood of exposure whenever possible.

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