Wildfires will get worse with climate change. This will not only endanger those living near the blazes, but also threaten the health of millions of Americans from wildfire smoke that is capable of drifting hundreds of miles. This is all according to a new report by the Natural Resources Defense Council.

Communities need to protect themselves from the health risks that arise from wildfire smoke exposure, which include asthma attacks, pneumonia, and other more serious chronic lung diseases. The report, titled “Where There’s Fire, There’s Smoke,” suggests that the U.S. needs to take action to curb the threat of climate change.

“There’s trouble in the wind: What blazes in Texas rarely stays in Texas. Wildfire smoke can pose serious health risks to people hundreds of miles away from the sources of fires,” said Kim Knowlton, a senior scientist in NRDC’s Health and Environment Program, who directed the analysis. “Wildfire smoke already clouds the skies of millions of Americans and because climate change will fuel more wildfires, that danger will rise.”

“Communities need safeguards against this peril, and our country needs standards to curb the unlimited carbon pollution from power plants that’s driving climate change,” she added.

This study was based on smoke data collected from the 2011 wildfire season, which is considered one of the worst in recent decades. It was found that the area affected by smoke is 50 times greater than the area burned by fire. About two-thirds of Americans lived in counties affected by smoke conditions in 2011. Many states battled large wildfires that year, but the study found that among the top 20 most affected states, six that experienced no major fires still had to cope with more than a week of medium to high density smoke conditions during the year.

The states with the greatest numbers of residents affected by wildfire smoke conditions for a week or more in 2011, according to this report, were: Texas, Illinois, Florida, Missouri, Georgia, Louisiana, Michigan, Alabama, Oklahoma and Iowa.

“The clear takeaway is that wildfires, smoke and the conditions that increase fire risk are national health concerns that spread well beyond the borders of local fire perimeters, conditions that are only projected to worsen with climate change,” the report says.

NRDC used smoke data from federal weather satellites and also looked at the locations of Environmental Protection Agency ground-based air quality monitoring stations.