(FORT WORTH, TX) — Two men were rushed to hospitals in critical condition after suffering from carbon monoxide poisoning while inside their converted bus in the infield at Texas Motor Speedway.

The Fort Worth Fire Department says the men, both in their 50’s, were found Sunday morning after bystanders reported the men appeared to be ill.  One man was taken to a nearby hospital, the other was flown to a hospital for treatment in a hyperbaric chamber.  Firefighters determined a gas-powered generator inside the bus wasn’t properly ventilated.