NIOSH has updated its criteria document governing occupational exposure to heat and hot environments, deciding that its current Recommended Alert Limits (RALs) and Recommended Exposure Limits (RELs) can remain unchanged. “It was determined that the current RALs for unacclimatized workers and RELs for acclimatized workers are still protective for most workers,” the document says. No new data were identified to use as the basis for updated RALs and RELs. Most healthy workers exposed to environmental and metabolic heat below the appropriate NIOSH RALs or RELs will be protected from developing adverse health effects,” the document says. But NIOSH decided to remove the ceiling limits for acclimatized and unacclimatized workers after finding that many workers live and work in temperatures above those limits. Despite leaving the standards in place, the document identifies two newer areas of research that will likely continue to grow: the effects of climate change on workers and how heat stress affects the toxic response to chemicals.
