Joel Eisiminger was racing to save homes in Northern California from a fast-spreading wildfire when a crewmate noticed that one side of his face was suddenly drooping so much that his mouth hung open.

In his six years fighting fires, Joel had tumbled down burning hills, endured full-body rashes from poison oak and inhaled plumes of smoke that left him gasping for weeks. But he had never felt as bad as he did on this morning in July 2024. He didn’t want to let down his crew, so he kept working deep in the forest until a medic told him to get to a hospital. He might have had a stroke.

As the doctors ran tests, Joel grew sicker. Within days, he was too exhausted to walk. On the eve of his 25th birthday, he received a diagnosis: acute myeloid leukemia, an aggressive, often fatal blood cancer that usually strikes people more than twice his age. Joel told the doctors he was not a regular smoker and had no family history of blood cancers. But he did have one risk factor: his job.

For decades, wildfire fighters have been sent to work in toxic smoke without masks or warnings about long-term health risks, The New York Times has reported. They inhale poisons that are linked to more than a dozen kinds of cancer, including leukemia. Many are falling gravely ill, and some are dying at young ages.

But when these firefighters get sick, they don’t all receive the same help.

About two-thirds of the country’s 40,000 wildland firefighters work for state and federal agencies. By law, many of their cancers are assumed to be job-related, and their workers’ compensation benefits are automatically approved.

The other firefighters — about 14,000 — are like Joel. They work for private companies that the government hires to shore up its ranks against a growing wildfire threat. Reliance on these contract crews has more than doubled since 2019, as climate change drives more extreme fire seasons. They have fought alongside federal workers in every major fire of the last decade.