Smoke from wildfires causes a cascade of changes in the proteins in the blood of firefighters, according to a groundbreaking study by researchers from the University of Arizona School of Public Health. The researchers found 60 different changes in blood proteins in samples taken from 42 firefighters who battled the Los Angeles wildfires that charred 23,000 acres and forced 10,000 people to flee their homes. Those changes in serum proteome are associated with a potential increased risk of cancer, abnormal cell growth, immune system dysfunction and inflammatory response. …The findings are the latest to highlight the health risks facing wildland firefighters, who for decades have actually been barred from wearing protective masks on the fire lines for fear it would limit their work and lead to overheating. The Forest Service recently shifted its policy to allow firefighters to wear masks if they choose.