Across the country, wildfire fighters work for weeks at a time in poisonous smoke. Across the country, wildfire fighters work for weeks at a time in poisonous smoke. The government says they are protected. The government says they are protected. We tested the air at one fire to find out why they are still dying. We tested the air at one fire to find out why they are still dying. Across the country, wildfire fighters work for weeks at a time in poisonous smoke. Across the country, wildfire fighters work for weeks at a time in poisonous smoke. The government says they are protected. The government says they are protected. We tested the air at one fire to find out why they are still dying. We tested the air at one fire to find out why they are still dying.

It’s July and the Green fire is tearing through Northern California. An elite federal firefighting crew called the La Grande Hotshots has been sent to help. The 24-person crew has been working for days on the front lines, where invisible toxins hide in the thick haze.

More than 1,000 firefighters are on the fire. Several crews, including the La Grande Hotshots, are trying to contain the flames by building a trench of bare earth that will stretch from a road to a river bank. They’re doing this at night, in hopes that the cooler air will tamp down the smoke.

The crew knows that they’re risking their health.

The La Grande hotshots on a