DALLAS, TEXAS: A judge has refuted the plea to stop the execution of a Texas inmate who has alleged the drugs he is due to be injected with are unsafe.

Jedidiah Murphy has filed a lawsuit after the drugs were exposed to extreme heat and smoke during a recent fire.

However, according to the Texas Attorney General's Office, testing done on the samples after the fire show that the drug used in executions, pentobarbital, "remain potent and sterile." The 48-year-old convict is set to be executed on Tuesday, October 10.

Jedidiah Murphy has spent the last two decades on death row

Murphy, who has spent the last two decades on death row, fatally shot 80-year-old Bertie Lee Cunningham of Garland, a Dallas suburb, during a carjacking in October 2000.

On August 25 this year, a fire took place in the administration building of a prison unit in Huntsville.

The execution drugs that the state uses are kept in the building and Murphy's attorneys claimed in a lawsuit filed on Wednesday in a federal court in Austin, that the drugs were exposed to excessively high temperatures, smoke and water as a result of the fire.

What did the lawsuit state?

"When pentobarbital is exposed to high temperatures, it can quickly degrade, compromising its chemical structure and impacting its potency," the lawsuit said.

"This creates substantial risks of serious, severe, and superadded harm and pain," according to the lawsuit.

Murphy's attorneys alleged in a lawsuit filed on Wednesday, October 4, in federal court in Austin, that during an August 25 fire that caused "catastrophic damage" to the administration building of a prison unit in Huntsville, the execution drugs the state uses were exposed to excessively high temperatures, smoke and water.

What did the Huntsville Fire Department report state?

According to a copy of a Huntsville Fire Department report included in the lawsuit, a prison guard and a fire captain entered the burning building to check "on the pharmacy," but as they approached the third floor, they had to evacuate because "the area was about to be overtaken by fire", Associated Press reports.

Amanda Hernandez, a TDCJ spokeswoman replied, "TDCJ has viable execution drugs available", in response to questions about what kind of impact the fire might have had on the execution drugs and the area where they are stored.

Why did the judge deny Jedidiah Murphy's request to stay his execution?

US District Judge Robert Pitman denied Murphy's request to stay his execution in an order issued Friday evening, saying the test results of the pentobarbital samples undermine Murphy's claims that all of TDCJ's execution drugs were damaged in the fire.

"As a result, Murphy's claim that the so-called 'fire-blighted' pentobarbital is sure or very-likely to cause serious illness or suffering is meritless," Pitman wrote in his 10-page order.

Murphy's lawyers also claimed the criminal justice department is using expired execution drugs, an allegation made by seven other death row inmates in a December lawsuit.

However, Pitman said there was no validity to these claims as well and there was nothing to support Murphy's allegations "that TDCJ's current execution method is sure or very likely to cause needless suffering and illness."

The Texas attorney general's office submitted a laboratory report of test results completed in late September of two pentobarbital samples in response to Murphy's lawsuit.

One sample had a potency level of 94.2% while the other was found to be 100% potent. According to the report, both samples also passed sterility tests and had acceptable levels of bacterial toxins.

The lab report "also undermines Murphy's claim that TDCJ is improperly using expired drugs in its executions - the Defendants' testing shows that, even if Murphy's allegation that the drugs are expired is true - which it is not - they remain potent and sterile," the attorney general's office wrote in its response.