SAN FRANCISCO (AP) – Researchers are studying whether firefighters suffered any toxic exposure in last month’s deadly Northern California wildfires. The San Francisco Chronicle reported Sunday that researchers plan to take blood and urine samples from 200 firefighters for the study. A cancer-research organization of the San Francisco firefighters’ union is contributing $100,000 for the study. California state health officials and toxic-substances officials are assisting the work. Wildfires that broke out Oct. 8 killed at least 43 people over a half-dozen counties in Northern California. Researchers say it’s important to test for any exposure to toxins as soon as possible after the fires.