(KTXL) A worker who was rescued after losing consciousness inside a gas storage tank at a Sacramento, California Costco died at the hospital, fire officials announced Monday.

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Firefighters responded to a call at the Costco on Expo Parkway at around 10:45 a.m., according to the Sacramento Fire Dept. (SFD).

The unidentified male employee did not work for Costco, but for Ponder Environmental Services, a company that cleans gas and oil tanks.

SFD said once the worker got down the ladder into the empty tank, a coworker said the man slid down the last portion of the ladder and passed out amid heavy fumes. When firefighters arrived at the scene, the rescue team set up a tripod with a rope system to pull him out.

On Monday, fire officials weren’t immediately sure if the worker had passed out from the gas fumes or had experienced a medical emergency after making his way down.

Due to the lack of oxygen caused by the fumes, responding firefighters had to use supplemental air around the hazardous environment inside the tank.

After the man was pulled out, he was loaded into an ambulance, CPR was administered, and he was rushed to the hospital, where he died.

Occupational Safety and Health Administration officials also responded Monday to investigate what happened before firefighters arrived, Sacramento FD said.

Sacramento Fire spokesperson told Nexstar’s KTXL that crews continued to monitor the air quality in the area Monday afternoon, and the fuel tank was not a threat to the public.