URGENT UPDATE: New research reveals alarming levels of carcinogenic hexavalent chromium (chromium-6) in the air over Los Angeles, detected as recently as March 2023, more than two months after devastating wildfires swept through the region. Researchers found concentrations of this hazardous pollutant up to 200 times higher than baseline levels, raising immediate health concerns for residents in affected areas.
The study, conducted by environmental engineer Michael Kleeman and his team at the University of California Davis, sampled air from debris cleanup zones around the Eaton and Palisades fires. They reported values ranging from 8.1 to 21.6 nanograms of hexavalent chromium per cubic meter in the hardest-hit neighborhoods of Altadena and Pacific Palisades. While these levels fall below the National Institute for Occupational Safety and Health’s exposure limit of 200 nanograms, they exceed the EPA’s indoor limit of 0.1 nanograms per cubic meter.
Officials are reacting swiftly. The South Coast Air Quality Management District stated that while the study’s sampling was limited, they do not currently perceive an immediate health risk from hexavalent chromium. However, the study’s findings, available on the preprint server Research Square, have prompted researchers to alert both policymakers and the public about this potential danger.
Hexavalent chromium is notorious for its health risks, linked to increased chances of lung, nasal, and sinus cancers. The fires have amplified its toxicity, as heat can convert less harmful chromium III into this hazardous form. Research indicates that wildfire smoke and ash can contain significant amounts of this pollutant, explaining why Kleeman and his team expected to find elevated levels.
What surprised the researchers was the remarkably small size of the detected particles—most were under 56 nanometers. These nanoparticles pose a higher risk because they can penetrate deeper into the lungs and even enter the bloodstream, potentially impacting major organs. Kleeman noted, “Nanoparticles smaller than 50 nanometers can cross cell membranes, meaning they can get deeper into our bodies than larger particles.”
While the findings are concerning, Kleeman urged caution rather than panic. He plans further investigations to determine whether airborne hexavalent chromium levels have returned to normal and to identify potential sources of pollution.
As California grapples with escalating wildfires due to climate change, understanding the implications of this newly identified threat becomes increasingly critical. “We all need to work together to adapt to this new reality,” Kleeman emphasizes.
Residents of Los Angeles and surrounding areas are encouraged to stay informed as more data becomes available. This developing situation underscores a growing public health challenge as climate change exacerbates the frequency and intensity of wildfires, leaving behind lasting impacts on urban air quality. Stay tuned for more updates as this story unfolds.