MARYLAND HEIGHTS, Mo. – Fire and EMS are investigating after an unconscious man was rescued from an underground sewer Wednesday morning in Maryland Heights.

The firefighters’ rescue went like clockwork. It happened shortly before 11 a.m. near the intersection of Dorsett and Fee Fee Road.

“Ended up being a confined space rescue, where we had a worker unconscious at the bottom of the sewer,” Maryland Heights Fire Captain Robert Daus said.

The man was working eight feet down and was trapped in a 21-inch in diameter pipe. The hydrogen sulfide levels were high.

“It did appear there wasn’t sufficient ventilation at the time that led to some building up some sewer gases that rendered the victim unconscious,” Daus said.

Firefighters began pumping in fresh air.

“Immediately the person started coming around,” Daus said.

Firefighters began their rescue in a very tight spot using special equipment including smaller air tanks that allow them ease of movement underground.

“It’s not for the claustrophobic at all when it comes to that type of technical rescue; usually one or two guys make the rescue,” said Assistant Fire Chief Steve Rinehart.

If a firefighter is claustrophobic, they still play an important role supporting the rescue from the outside, manning the ropes, and pumping in fresh air.  Fire officials will turn over what they learned on the scene to the feds.

“There’s OSHA standards. This incident will be investigated by OSHA as well,” Daus said.​