The climate-fueled heatwave broasting the southern U.S. has already killed at least 11 people in Texas, 21 people in northern Mexico, and an unknown number of migrants and people incarcerated in Texas jails. At least nine people incarcerated in Texas jails have died since the beginning of the heatwave, including Tommy McCullough, a 35-year-old who died of what the prison system says was cardiac arrest after mowing in the sun outside a Huntsville prison last Friday — a day on which the lowest temperature was 80°F.

More than two-thirds of Texas prisons lack air conditioning or even adequate cooling — nevertheless, the state prison system has not acknowledged a single heat-caused death in over a decade despite numerous wrongful death lawsuits and its agreement to install air conditioning in one facility in order to settle a civil rights lawsuit.

McCullough told a friend the night before he died that prison guards refused to bring him water, his sister Kristie Williams told the Texas Tribune. It’s a complaint many other inmates have relayed to their families in recent weeks. “He had so much life ahead of him,” Williams said. “There was so much he wanted to do and he was capable of doing. He just had to get this behind him.” (Heat deaths: CNN; Prison deaths: Texas Tribune, KXAN; Climate connection: New York Times $; Climate Signals background: Extreme heat and heatwaves)