Metalworking Fluids Require Careful Monitoring

Oil and water don't mix, and when you add emulsifiers, defoamers and other chemicals to the liquids that clean, lubricate and cool metals during the milling process, the result can be dangerous.

The chemical composition of modern metalworking fluids have evolved from those on which OSHA bases its current standards. The Hartford Financial Services Group, a major insurer of metalwork shops, wants companies to understand that federal standards may not have kept up with changes in fluid formulations.

Existing standards for metalworking fluids were promulgated for simple oils, like mineral oil, that were used with machining tools for over 100 years between the 1860s and the 1970s. Today, a significant portion of metal processing machines use sophisticated oil-and-water-based fluids, or fully synthetic fluids, that may bring with them different exposure issues. While OSHA focuses its resources on arsenic and other known dangers, metal workers in small and large operations could be inhaling or touching other chemicals at levels that may be dangerous to their health but nonetheless fall within federal guidelines.

This situation leaves metalwork shops in a tough position. Merely complying with current federal standards may not be sufficient to limit worker exposure. Tim Howe, assistant vice president of Loss Control at The Hartford, notes that some companies, in consultation with loss control experts and safety engineers, have adopted stricter standards in their operations.

"We're raising the issue of metalworking solvents because we know that informed companies can take can take the standards endorsed by the National Institute for Occupational Safety and Health (NIOSH) into consideration in their risk management strategies," said Howe.

He pointed out this is not a new issue: the UAW in 1993 petitioned OSHA for emergency regulations to protect workers from the risks of occupational cancers and respiratory illnesses due to exposure to these chemicals. Four years later, the secretary of labor established an advisory committee to recommend exposure standards. In 1999, the advisory committee endorsed standards proposed by NIOSH.

When OSHA failed to take action to adopt and implement these standards, the UAW and United Steel Workers of America filed a petition asking the U.S. Court of Appeals for the Third Circuit to review OSHA's failure to set formal exposure limits for these new substances. OSHA argued that it had more pressing issues to review and that it could not respond to all issues before it with the same level of priority. In January, the Third Circuit denied the petition for review, thereby upholding OSHA's position that its resources were better directed to larger issues with significant mortality risks.

"Protecting workers is a complicated matter requiring heavy detective work, the right tools and a thorough review of businesses operations through the lens of loss control," Howe explained. "Exposure can vary from machine to machine within the same shop and can be affected by something as simple as how often a protective apron is changed."

He explained that a machinist using a predominantly oil-based fluid might, for example, be more likely to change an oil-soaked apron each day and ultimately have less exposure to harmful chemicals or metals then a worker using water-based fluids that dry in the apron. The chemical levels in the apron would grow more concentrated as the apron was repeatedly soaked. Since the fluid also mixes with tiny particulates during machining, the likelihood of skin problems increases, according to medical experts.

"Most loss control experts are much more comfortable with NIOSH's recommended exposure standards of 0.5 milligrams per cubic meter of air for 8 hours near the machines, rather than the existing OSHA standards of 5 milligrams per cubic meter for mineral oil mist or 15 milligrams per cubic meter for particulates," said Howe. "Most safety professionals agree the standards proposed by NIOSH and endorsed by OSHA's advisory panel appear to be well thought out and to more accurately reflect current exposures."

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