Philly changed the way the world views heat disasters and may have saved thousands of lives

The temperature had reached 100 degrees for three consecutive days in Philadelphia, three straight in New York, and two in Baltimore.

But something was dramatically different in Philadelphia during that historic July heat wave in the East 30 years ago.

People in Philly were dying. Lots of them. Yet heat deaths were strangely scarce in New York, Baltimore, and other cities during what was a brutally hot summer.

Philly was feeling the heat on two fronts. Were these real numbers? And if they were, how could city officials be so inept?

Among those who wondered what was going on were David L. Cohen, who then was Mayor Ed Rendell’s chief of staff and is now U.S. ambassador to Canada, and his boss.

What neither Rendell nor Cohen realized at the time was that Philadelphia and its medical examiner, the late Haresh Mirchandani, were about to change the way the nation, and the world, view heat dangers. In the process, say health experts, the city was ringing lifesaving alarm bells.

“It’s quite possible that thousands of lives have been saved,” said Laurence Kalkstein, a climatologist and heat-mortality expert who helped develop Philadelphia’s heat-wave warning system that went into effect two summers later. Variants eventually were adopted in other cities.

Mortality statistics support that assertion. The Southwest saw historic heat this summer, and climate researchers have warned that longer and more-intense heat waves can be expected as the planet’s temperature rises.

However, in the first 22 summers of the 21st century, heat deaths declined dramatically in Philadelphia compared with the 1990s. Only one has been reported this year in Philly, and just 44 from 2013 through 2022, compared with 400 in the 10-year period ending in 2002. And they have been trending downward across the country.

Officially, Philadelphia recorded 118 heat-related deaths in the summer of 1993, most of them among older people who lived alone. Unofficially, not everyone believed it.

“There was a fair amount of criticism that it was an overcount,” said Dean Iovino, a lead meteorologist at National Weather Service office in Mount Holly, who worked in the Philly office that summer.

The medical examiner for Detroit, where Mirchandani was stationed before he came to Philadelphia, dismissed the total and suggested it was the result of “sloppy” work.

And if the numbers were accurate, that would raise serious questions about an administration that had been in office just 18 months, Cohen said: People might well ask, “‘Why can’t the city take care of its aged population.’ ” Rendell sought answers from the Medical Examiner’s Office and the Health Department.

What Mirchandani had done was to expand the definition of heat deaths to include those in which heat had been determined to be a contributing cause. In the past, the strict criterion was hyperthermia, a core body temperature of 105 degrees at the time of death.

Mirchandani reasoned that in a prolonged hot spell, his investigators wouldn’t be able to get to all the bodies quickly enough to ascertain their body temperatures. So he told them to look for forensic evidence, such as closed windows with fans operating.

That summer, in an Inquirer interview, Mirchandani said that “on a typical day, we see 15 cases ... and if it suddenly jumps to 40 cases when the temperature is 100 degrees and we go out and see all the windows closed,” it was reasonable to conclude that heat was a factor in the excess deaths.

The mayor was sold.

“There was some legitimate questions,” Cohen added, “but we had what we thought what were really legitimate answers.”

Both NOAA and the Centers for Disease Control and Prevention agreed, concluding that not only was Mirchandani right, but that his method should become the standard. At it turned out, the CDC’s “excess mortality” figures — the number of deaths above daily averages — tracked neatly with Mirchandani’s running counts.

One person who concurred with Mirchandani’s method was Edmund Donoghue, the Cook County chief medical examiner in 1995, when 739 heat deaths were recorded in Chicago.

Donoghue also endured blowback, including from Chicago Mayor Richard Daley, who opined that the counts were inflated. Donoghue didn’t flinch, and on Monday said, “I wouldn’t do anything differently.” He added that he was grateful to Mirchandani.

When the CDC backed Philly’s system, said Donoghue, now a professor of pathology at Western Michigan University, in Kalamazoo, “that really helped me.”

The tragedy in Chicago further affirmed Mirchandani’s methodology, said the weather service’s Iovino.

“We are fortunate that Philadelphia did that in 1993,” said Eric Klinenberg, New York University sociology professor who wrote Heat Wave: A Social Autopsy of Disaster in Chicago. “People are aware of the dangers of heat waves in a way that they weren’t before.”

He said that traditionally, news media treated them as basic feature pieces, with images of eggs frying on sidewalks. “Heat waves don’t make for great TV,” he said.

“They target, poor, old, sick Black people,” he said. “We have a tendency to treat them as expendable. Heat waves remain silent and invisible killers of silent and invisible people.”

Klinenberg, a Chicago native and now a sociology professor at New York University, recalled that in 1995 he was living in Paris, where he read about the disaster in his hometown.

Five years later he would begin his investigation for his book, which was published in July 2002, the year before one of the worst natural disasters in world history — a heat wave in Europe that killed tens of thousands.

Klinenberg said he is haunted by the similarities between what happened there and in Chicago, and has wondered if the tragedy could have been averted had leaders in the European community had been more aware of the Chicago experience.

The shock of the 1993 death toll in Philly, the highest on record, moved the city to mobilize a “state-of-the-art” heat-response system, said Cohen.

It included setting up cooling centers, alerting block captains to look in on older neighbors, having the Philadelphia Corporation for the Aging, and launching a public campaign to advise people to open their windows if they didn’t have air-conditioning.

It went into effect in 1995 and through the summer of 1998 it had saved 270 lives, according to a 2004 study published in the Bulletin of the American Meteorological Society. The annual cost was a mere $100,000.

Through subsequent administrations Philadelphia has retained variants of the original system, and similar programs have been adopted in Chicago, Cincinnati, Dayton, and other cities, said Kalkstein.

“We weren‘t trying to be heroes,” said Cohen. “We weren’t trying to change the world.”