Texas, the state with the largest prison population in the US, is coming under mounting legal pressure to address the ongoing crisis of brutal heat in its cells, as extreme summer temperatures expose inmates to suffering, illness and even death.

The Texas department of criminal justice (TDCJ), the state agency that runs dozens of prisons, has been hit by a new wrongful death lawsuit by the family of Jason Wilson. The inmate was found dead in his solitary confinement cell at the Coffield unit in July 2024.

The family’s civil complaint, lodged in a federal district court in Houston, accuses the state of inflicting cruel and unusual punishment on the prisoner “that led to his death in a brutally hot, un-airconditioned cell”. Refusal to provide Wilson with cool water and regular showers, combined with the lack of air conditioning and a failure to check routinely on his wellbeing, “caused him immense suffering and death”.

His plight was the result of “deliberate indifference” and “intentional discrimination” on the part of the Texas authorities, the suit says.

The new wrongful death lawsuit comes as Texas is already awaiting the outcome of a separate federal court action in Austin over the heat crisis. An alliance of advocacy groups is calling on a federal judge in the western district of Texas to order the state to introduce air conditioning in all its prisons over the next three years.

A ruling in that case is expected within months.

The legal crunch is coming to a head just as searing summer heat yet again pummels Texas prisons. Of the state’s 141,000 prisoners, more than 85,000 are held in cells without air conditioning where internal temperatures regularly exceed 115F (46C) in summer months.

A high of 149F has been recorded. At such extremes, individual inmates can experience physical and mental breakdown, and those who are particularly vulnerable as a result of co-morbidities can suffer fatal heatstrokes.

Desperate inmates have been known to spill dirty toilet water on the concrete floors of their cells and lie in it in an attempt to cool off.

TDCJ has accepted that there were three heat-related deaths in its prisons in 2023, but has denied any such fatalities since then. One of the three deceased inmates, Patrick Womack, 50, was found unresponsive in his cell in August 2023 with a core body temperature of 106.9F.

In the Coffield unit the temperature log inside the prison recorded 107F the day before Wilson died. This summer, the heat register for Coffield has again been intense.

Anderson county, where the prison is located, recorded temperatures of 100F or hotter on 17 out of 30 days in June. Those outside temperatures are known to rise even further inside the prison, especially at night.

Brittany Robertson, who acts as an outside advocate for hundreds of Texas inmates, said that she had been receiving distress signals from several individuals in recent days complaining of a dearth of cool water.

“The cool down showers are still at regular shower temperatures, which won’t do anything to lower the body temperature,” Robertson said. “The dire conditions are made worse by electricity and water outages.”

One recent communication from James, an inmate in the Coffield unit, sounded the alarm in chillingly similar terms to urgent pleas Robertson received from Wilson shortly before he died. James wrote: “I was stuck 20hrs with no running water or a toilet. Wow. Not one rank walked the line lastnite or even came to resolve the problem.”

At the time of his death, Wilson was locked up in his solitary confinement cell – known as restrictive housing in Texas – for 23 hours a day. He was known to have co-morbidities including his weight that rendered him officially obese, and as such was supposed to have been given intensive wellness checks during hot spells.

The night before he died, however, the officer responsible for carrying out the last wellness check of the day failed to complete it. The officer later said the unit was struggling from understaffing and he was “tired due to the heat”.

Ronnie Wilson, Jason Wilson’s father who has brought the wrongful death lawsuit, told the Guardian that he had no idea that his son was enduring such extreme suffering until after he died. When he began digging into the conditions at Coffield, Ronnie was told that the institution was colloquially known by staff as the “glass house” because of the way the sun beat down on it.

Texas is facing possible punitive charges in the wrongful death suit. Wilson said that money wasn’t the issue – he wanted to see justice done for his son and necessary changes made by the state.

“Too many people are dying. My son was sentenced for what he did wrong, but he didn’t get a death sentence. He wasn’t meant to suffer like that, like he was slowly being put to death.”

The Guardian approached TDCJ for its response to the accusations leveled against it, but the agency declined to comment due to pending litigation.

The calamity inside Texas prisons is predicted to steadily intensify as temperatures rise under the climate crisis. Climatologists project that Texas is likely to warm by up to an additional 5.1F (2.8C) by 2050.

The cost of introducing air conditioning into all of Texas’s prisons has been estimated at $1.3bn. That is well within the state’s reach – it currently has a rainy day fund that is capped out at $27bn.

To dip into the coffer, known officially as the economic stabilization fund, the legislature would have to pass a two-thirds vote. But Erica Grossman, a lawyer who is acting as counsel on both the wrongful death suit and the federal action in Austin, said that prison authorities were continuing to deny the scale of the problem.

“You don’t get the funding unless you explain to the legislature why you need it, and articulate the severity of the crisis,” she said.

Grossman said that the state had tolerated unconstitutional, brutal conditions inside its cells for years. “It continues to tolerate it, to cover it up, rather than take accountability. Prisoners in solitary confinement like Jason Wilson are basically being cooked to death.”