BATON ROUGE, La. (AP) — The warden of the Louisiana State Penitentiary apologized to a federal judge Tuesday, acknowledging he tried to cool death row cells while court-ordered temperature monitoring was going on to determine if heat levels were unsafe.

Burl Cain, warden at the Angola prison, said he made a mistake when he added temporary awnings on some of the death row cell blocks and tried to soak some of the buildings during temperature data collection.

“We really messed up,” Cain told U.S. District Judge Brian Jackson.

Jackson had ordered collection of 21 days of temperature data in advance of the trial for a lawsuit claiming that three condemned killers are forced to live in dangerous heat conditions in the death row building, which has little climate control beyond window ventilation and fans.

The judge said Cain’s actions could have damaged the data collection.

“The evidence may have been compromised due to your act,” Jackson said during testimony on the trial’s second day.

Cain said that wasn’t his intention. He said he thought he could use the improved temperature monitoring installed for the lawsuit to determine if remedial measures could help lower the heat for inmates, by comparing it to data in areas where those efforts weren’t tried.

“In our intention to do something good, we really violated the order,” Cain said, taking responsibility for the decision.

Cain said neither effort was successful at making a substantive difference, because the water pressure was too low to use the soaker hose on the concrete prison walls and the awnings didn’t change the heat level.

Jackson temporarily stopped questioning of Cain in the trial so that he could ask his own questions, all about the efforts prison officials took to alter the temperature on death row. He told Cain, warden of the prison for 18 years, that he may consider sanctions against him in a later court proceeding.

The judge questioned why Cain ignored an email sent by the assistant warden who oversees death row reminding prison officials about evidence preservation for the case.

He also asked Cain why the awnings were put up so quickly, erected by prisoners in the middle of the night. And he questioned why Cain didn’t try awnings and other cooling measures when the inmates first filed complaints about the heat.

“It was an honest mistake. I really apologize,” Cain told the judge.

Cain said he didn’t tell Department of Corrections Secretary Jimmy LeBlanc, also a defendant in the lawsuit, about the efforts until after the awnings were installed.

The lawsuit was filed in June on behalf of condemned killers Elzie Ball, Nathaniel Code and James Magee, saying the south Louisiana heat conditions violated the death row inmates’ constitutional right to protection from cruel and unusual punishment and federal law requiring reasonable accommodations for people with disabilities.

All three men have hypertension, along with other health conditions and have increased vulnerability to the heat, the lawsuit says. They testified over two days about heat that made them feel dizzy, light-headed and nauseous.

“In the morning times, it feels like a sauna … In the afternoon time, it turns into like an oven,” Magee said Tuesday.

Jackson didn’t say when he would rule in the lawsuit, which was filed by the Promise of Justice Initiative, a New Orleans-based nonprofit group that advocates on behalf of indigent defendants.