Antoinette D. Swan, 57, was found in a hot apartment without working air conditioning — the temperature read 94 degrees.

Francisco Hernandez-Lucero, also 57, was found unresponsive in a hot car with a blood alcohol level three times the legal limit.

Ruth P. Howard, 90, was found in her garden, still in work gloves, during a hot week.

Paul L. Boyd, 50, was working on a farm on a hot day when he was stung by a bee. About 30 minutes later, he was found unresponsive.

And Ronald Silver II, 36, was collecting trash in his job as a sanitation worker in Baltimore on a hot day when he collapsed after asking for water.

These are just five of the 25 Marylanders who have died from heat-related illness this year, the most since 2018, according to the Maryland Department of Health. Heat is an insidious killer that exacerbates existing health conditions and especially targets vulnerable populations, including children and older adults. Experts predict climate change will make Maryland hotter and wetter in the future, increasing the risk of heat-related illness.

Of the 25 people who have died this year, 19 were male and 14 were 65 or older, according to data from the health department. None of the reported heat deaths was a child.

“We clearly have not seen a decrease in heat or in extreme heat in the state. We are clearly continuing to see the impacts of climate change,” said Dr. Cliff Mitchell, director of the Maryland Department of Health’s Environmental Health Bureau.

Mitchell said there is not a simple explanation for why heat deaths dropped so much in 2023 and 2022 compared to this year and previous years. It’s possible there was a ripple effect from restrictions and behavior changes around COVID-19, he said.

But, he said, “I don’t think COVID alone is responsible” for the decline.

“As we see our temperatures increase, particularly higher temperatures earlier in the year, I am concerned about what the implications are for how we move forward” in terms of dealing with heat illness, Mitchell said.

The Office of the Chief Medical Examiner provided 18 autopsy reports connected to heat-related deaths to The Baltimore Banner. Another two reports were not completed by publication, and the other five heat-related deaths did not result in autopsies, officials said.

Most of the cases with autopsies — 13 of them, including Swan, Howard and Boyd — mentioned heart disease. Eleven of them mentioned a hot home or car, and three of them, including Hernandez-Lucero, mentioned alcohol intoxication.

Those are just some of the factors that make a person more susceptible. Robyn Gilden, a nurse and environmental expert at the University of Maryland School of Nursing, said additional risk factors for heat-related illness or death include whether a person works outside, whether they’re overweight and age.

The stress heat places on the body can worsen preexisting conditions, Gilden said.

“Heat just makes everything worse,” she said.

How heat kills

Illness and death from extreme heat are “an issue of regulation,” said Dr. Chris Lemon, a physician in emergency medicine with Johns Hopkins Medicine. The body’s ability to regulate core temperature begins competing with how hot it is outside.

You start sweating, breathing harder. Your pulse increases as your heart tries to move blood to your skin to dissipate heat from your core. Maybe your leg starts cramping.

If you don’t take steps to cool down and recover, your body may move into heat exhaustion.

Your skin could turn pale and moist. You may develop a headache, fatigue or weakness. You could become nauseated and vomit or have diarrhea. Your body is trying to compensate.

“The warning light is on the engine,” Lemon said. These are the signs of heat exhaustion.

If you don’t get treatment quickly, your body will enter heatstroke, a medical emergency. You may go from some confusion to “full-on altered mental status” or have a seizure, Lemon said. Your skin will be warm and dry, and you’ll likely have a temperature over 104 degrees.

“As you get further down this pathway, you’re losing awareness of how serious this is becoming,” Lemon said.

The heat begins to cause problems at the cellular level, Lemon said — proteins and enzymes in your body begin to denature, or stop working, and a series of “cascading failures” will begin.

“You get multisystem organ failure,” Lemon said, “which is what ends up killing you.”

A person experiencing heat illness needs to be cooled down. They should be moved into a cool building or shade to rest. Heatstroke needs to be treated and managed by doctors.

Even if a person experiencing heatstroke gets treatment, there could be irreversible organ damage — it varies patient by patient, based on whether a person has preexisting health conditions, Lemon said. He compared entering severe heat stress to running a car’s engine without oil.

“Even if you replace the oil, there’s a chance the engine will never be the same again,” he said.

Experts said it’s possible the number of heat-related deaths each year is higher than ends up reported because of the way heat complicates other health factors.

Mitchell said, in Maryland and everywhere, it’s “quite likely that there is some portion of the overall death rate that is affected by extreme heat events and extreme weather events.”

The future of heat

Many experts consider deaths from heat preventable because the risks and warning signs are so well understood. And some officials, including in Maryland, are working to protect more people from heat.

Maryland this year became the first state on the East Coast to adopt workplace heat standards. The rules require all workers to have access to water and breaks when the temperature gets too high. There are also training requirements to help people recognize signs of heat illness.

Those standards came too late for Silver, the Baltimore sanitation worker who died while working a route over the summer. Some experts, including former deputy assistant secretary of labor at the Occupational Safety and Health Administration Jordan Barab, say the standards could have saved Silver’s life.

“The one thing they’ll [officials will] have to do now is promote the standards,” Barab said. “They’ve got some time until the next hot season. They’re going to have to do a lot of work to prepare.”

Mayor Brandon Scott’s administration hired a law firm to evaluate the Department of Public Works in the wake of Silver’s death. Some, including union leaders, criticized the selection of Conn Maciel Carey LLP for the evaluation because it is representing an industry group that it convened to work against proposed federal heat safety regulations.

The law firm’s report, published in late October, concluded that DPW had inadequate procedures for heat-related illness and confirmed complaints of a toxic work environment in which employees feared retaliation if they raised safety concerns.

The city has submitted a Heat Illness Prevention Plan to the state for review. It includes modifications to the work schedule when the weather gets too hot, among other things. It does not include an automatic “stop-work trigger,” which Conn Maciel Carey recommended.

Gov. Wes Moore joined the calls for a “full investigation” into Silver’s death. A spokesperson for the state Department of Labor said investigations are standard operating procedure in Maryland after any workplace death, and that Maryland Occupational Safety and Health is still investigating.

But it’s not just people working outdoors or in hot kitchens who are at risk. People who live in places with no air conditioning are, too.

Carol Ott, tenant advocacy director for Economic Action Maryland, said she’s been pushing for about a decade for Maryland to require air conditioning in rental units, much like heat is required.

She wouldn’t require landlords to provide central air — window units or box units would be fine, Ott said. She said some renters live in places without air conditioning, commute on public transit and then work outdoors or in a place with no AC, such as a warehouse.

“For a lot of people in Maryland, there’s absolutely no relief,” she said.