As wildfires have killed at least 50 people in California this week, many Americans have seen terrifying photos of homes ravaged by flames and a school bus charred from mustard yellow to dark amber. The photos may seem to suggest that nature is impartial with regard to who and what it harms. However, the effects of wildfires can’t be put down entirely to nature, and they are not equal.

A new study published in PLoS One, “The unequal vulnerability of communities of color to wildfire,” takes a “social-ecological” approach to determine wildfire vulnerability across the 70,000-plus census tracts in the United States. The researchers find that communities of color—specifically, Census tracts that are majority black, Hispanic, or Native American—are about 50 percent more vulnerable to wildfire compared to other Census tracts. These three groups are overrepresented among the 12 million socially vulnerable Americans for whom a wildfire event could be devastating. (Asian and Pacific Islander Americans were included in the study, but tended not to live in places prone to fire or with low adaptive capacity, defined below.)

“We looked at the problem similar to how people have looked at Katrina and other hurricane disasters, where you realize … the disaster part isn’t natural,” said Phillip Levin, one of the study’s authors, who is the lead scientist for the Nature Conservancy in Washington and a professor in the School of Environmental and Forest Sciences at the University of Washington. “The disaster part is the result of the social, political, and economic context in which the environmental event happens.”

The first map below shows wildfire hazard potential; the second, wildfire vulnerability. The latter takes into account both landscape wildfire risk and socioeconomic factors to discern how likely an area is to adapt to and recover from a wildfire. The researchers define adaptive capacity as “the ability of a census tract to absorb and adjust to disturbances, like wildfire, while minimizing damage to life, property, and services.” They measure it by using data from the Census’s 2014 American Community Survey on socioeconomic status, language, education, housing, and other factors.

So, considering hazard potential alone, the Southeast generally exhibits moderate scores, with few places having very high potential for extreme wildfires. But considering the threat from a social-ecological perspective, the Southeast stands out as a region of high vulnerability to wildfire.

The majority of the 29 million-plus Americans who live in areas with significant chance of extreme wildfires are white and socioeconomically secure. That obscures the fact that blacks, Hispanics, and Native Americans often have worse prospects for recovery from wildfires, for a number of reasons.

“What sort of gets lost, I think, is that people who have historically had less of a voice or less power, [and] are economically disadvantaged, are sort of invisible in this whole process,” Levin said.

For example, language barriers prevent some Hispanics from receiving evacuation orders. During a wildfire in eastern Washington state in 2014, the only Spanish radio station in that region at the time never received the emergency information. NPR reported in 2015 that Spanish-speaking farmworkers in the Pacific Northwest were particularly vulnerable to wildfires because emergency information didn’t reach them as quickly, a problem that a lack of internet access might exacerbate.

Black and Hispanic Americans are more likely to rent their home than own it. Living in multi-unit rental housing—especially if poorly constructed—can make it harder to escape wildfires, because “escape routes can be overcrowded and building-owners are less likely to pursue fire mitigation on their properties,” the paper notes. Also, renters are not eligible for much of the federal housing assistance that homeowner fire victims receive.

Native Americans are “highly overrepresented in all of the most vulnerable areas,” according to the study. The authors point to the policy of forced concentration on reservations as evidence that injustices committed over the course of American history have led to unequal vulnerability to wildfire today.

When wildfire overtook parts of Washington state back in 2014, the U.S. deployed the National Guard, but the study’s authors write that undocumented migrant farmworkers didn’t view them as “trusted helpers and messengers,” but rather as “government authorities and threats.”

For more equity in wildfire response and recovery, as the study demonstrates, experiences of communities of color need to be taken into account. Levin suggested one of the easier steps would be to improve the signs and other evacuation communications when they are translated into Spanish and other languages. Also, wildlife groups could ramp up their outreach to communities of color, so that they’re aware of fire prevention measures and included in the conversation well before disaster strikes.

“While some people are … beginning a slow and difficult process of recovery, other people don’t even have that ability. You’re just out of luck,” said Levin. “It’s these parts of the population that we were trying to highlight.”