Killer Heat Waves Are An Even Bigger Public Health Threat Than We Realize, CDC Warns

Public health officials have been underestimating the number of deaths resulting from heat waves, the Centers for Disease Control (CDC) said on Thursday. The problem is more serious than federal officials realized largely because heat deaths tend to disproportionately affect non-residents, who weren’t included in the CDC’s previous data.

Non-residents include undocumented immigrants, tourists, and migrant workers — groups that particularly suffer when it gets very hot. The CDC didn’t used to track the data for those groups, but the inclusion makes a difference. “About 15 percent of the heat-related deaths we have seen over 10 years are occurring in non-U.S. residents,” a CDC official, Ethel Taylor, explained to NBC News in reference to the agency’s most recent report. That adds up to about 1,000 people.

Forty percent of the deaths over the 10 years occurred in California, Arizona, and Texas. The CDC suspects that many of the people who died from extreme heat in those states were immigrants attempting to cross the border from Mexico. Farm workers who spend their time in the desert are also particularly at risk, as well as the rural poor who may not have access to air conditioning.

The CDC is continuing to raise awareness about how to avert heat illness, which can carry subtle symptoms that don’t immediately seem like cause for alarm. “Heat is kind of an insidious killer and it easy for people not to realize they are at risk,” Taylor explained to NBC News. The federal agency is urging local officials to identify their most vulnerable populations, like the poor and the elderly, before the summer heat hits.


Although heat fatalities have declined in the U.S. over the past two decades, public health officials warn that trend may not continue, largely thanks to climate change’s extreme weather patterns. 2012 was the warmest year on record so far, and this summer could end up setting new records. The situation is made worse by the increasing number of large storms, such as the derecho that hit the East Coast last July, that tend to knock out power for days on end. One recent report predicted that climate change will cause the death toll from extreme temperatures to dramatically increase in New York City over the next 70 years. That’s why some members of the scientific community have begun pointing to heat deaths as an method of effectively framing climate change as a public health issue, perhaps making it more personally relevant for Americans.

Of course, Americans are hardly the only ones affected by killer heat waves. In developing nations with more poverty and fewer energy resources, extreme heat is particularly deadly. Over 500 people have died in India since the beginning of this April as a result of a heat wave.