Phoenix area trails last year’s pace for heat-associated deaths, but investigations surge

PHOENIX – Despite the ongoing wave of excessive heat, metro Phoenix is trailing last year’s pace for heat-associated deaths.

However, the number cases under investigation is surging, according to Valley health officials.

The Maricopa County Department of Public Health has confirmed 25 heat-associated deaths this year, according to the latest weekly report, which runs through Saturday (July 22), 29 weeks into the year.

That was up seven from the previous week, but it was behind the 38 heat-associated deaths identified at the same point in 2022.

How many Valley deaths are under investigation for heat association?

The county was investigating 69 cases as of July 15, but that spiked to 249 last week, nearly equal to the 256 from this time last year.

A record 425 heat-associated deaths were recorded in the Valley in 2022, a 25% increase from the previous year.

Breaking down the data on heat-associated deaths in Maricopa County

A closer breakdown shows about a third of this year’s 25 heat-associated deaths were people age 75 and older.

Twenty of the deaths, or 80% of the total, were the result of outdoor heat exposure. Of the five indoor deaths, air conditioning wasn’t working in four cases and wasn’t being used in the other.

The homeless population accounts for 36% of the Phoenix area’s heat-associated deaths so far this year.

Heat-caused vs. heat-related

The county classifies heat-associated deaths in two ways: “heat-caused” or “heat-related.”

Heat-caused is used when heat is listed as a direct cause in the death certificate. Heat-related is for when heat exposure is mentioned in the death certificate but not as a direct contributor.

Of this year’s heat-associated deaths, 18 are classified as heat-caused and seven are heat-related.

How long does it take to confirm heat-associated deaths?

Sonia Singh, supervisor with the Maricopa County Public Health Department’s communications office, said the latest weekly heat-associated death reports don’t reflect the true toll of the ongoing heat wave.

“We will likely not have a complete count of deaths resulting from this heat wave for some time,” Singh said in a written statement to The Associated Press. “This is for a couple reasons: 1) the deaths are reported from multiple sources and may not come in to Public Health right away, and 2) these deaths sometimes take a while to go from a suspect case to a confirmed case.”

For instance, toxicological tests that can takes weeks or months after an autopsy is conducted could eventually result in many deaths listed as under investigation being changed to confirmed.

An example of this was seen in last year’s numbers.

At the end of last year, Maricopa County had reported there were 378 heat-associated deaths confirmed for all of 2022. By this spring, that number had grown to 425, the current number, as more deaths that were under investigation were confirmed as heat-associated. More than half of the deaths occurred in July in what was the hottest summer on record — a record that is likely to be broken this year.

The Associated Press contributed to this report.

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