Heat kills thousands of Americans each year, but federal tallies capture only a fraction of the toll. In southern Arizona, that danger has become especially visible inside manufactured homes, where aging structures, high cooling costs and extreme temperatures can turn private living spaces into deadly environments. The death of 76-year-old Sheri Petty in Tucson has become one of the clearest examples of how indoor heat exposure is affecting residents far from worksites or sidewalks.
A Tucson woman’s death put a number on an often hidden danger
Sheri Petty died after suffering heatstroke inside the manufactured home she shared with her daughter and granddaughter on the outskirts of Tucson, according to NPR’s Sept. 7, 2026 investigation. Her daughter, Tara Gentner, told NPR that paramedics found the home dangerously hot and that Petty’s body temperature had reached 106 degrees after the bedroom air conditioner and the home’s swamp cooler stopped working during a stretch of 100-degree-plus days in July 2025.
Petty was taken to a hospital after going into cardiac arrest triggered by heatstroke, Gentner said in the report. Petty died later that day at age 76. NPR reported that she had tried to get help repairing the cooler through county and private assistance programs, but no free or low-cost service was available in time and she could not afford the repair herself.
The case sits within a broader national finding. NPR and Boston University reported that roughly 9,000 Americans die from heat-related causes each year, a figure they said is more than five times the level reflected in federal statistics. Their reporting said official records radically undercount the toll, particularly when heat contributes to deaths that happen indoors and alongside existing medical conditions.
The local geography in this case is Pima County, where Tucson is located and where NPR reported one of the nation’s highest per-capita rates of heat-related deaths. The outlet said about 10% of the county’s housing is manufactured housing, sheltering roughly 100,000 residents. More than a third of those homes are at least 50 years old, according to the report, placing many households in structures built before stronger 1976 federal standards for insulation, wiring and construction took effect.
That age matters because older units often have thin walls, little insulation, leaky windows, aging coolers and electrical systems that may not reliably support air conditioning, according to University of Arizona geographer Mark Kear, as cited by NPR. The report also said many parks are heavily paved and have limited shade, conditions that can intensify surrounding temperatures.
What remains unclear is the full scale of households currently living with failed cooling systems or recurring outages across Pima County. The report describes repeated power losses in some parks and widespread affordability problems, but it does not provide a comprehensive public list of affected communities or a countywide count of homes with broken cooling equipment.
Researchers and public officials interviewed by NPR traced the risk to a combination of climate, housing and cost. Tucson now experiences about twice as many hot nights as it did in the 1990s, the report said, a shift tied to climate change and one that reduces the body’s chance to recover after daytime heat. Arizona State University geographer Patricia Solis said mapping in metro Phoenix showed mobile home parks clustering in areas with high heat death counts and relatively little utility-bill assistance.
Solis and her colleagues found that mobile home residents in Maricopa County are six to eight times more likely to die from heat-related issues than residents of traditional housing, according to NPR. Tucson heat team member Karina Martinez told the outlet that some residents cannot afford to run their coolers even when equipment works, while others face barriers tied to master-metered billing systems that can limit access to utility aid.
Pima County, Tucson and nonprofits have begun offering programs for insulation, electrical upgrades and cooling repairs, NPR reported, and local officials have also supported outreach in high-risk parks. But county housing rehabilitation specialist Joel Viers told the outlet those programs are often oversubscribed, meaning residents in older manufactured homes may continue to face a high level of risk during prolonged heat events even as assistance efforts expand.