His helmet securely sealed to his airtight suit, John Derouen slowly backed down the ladder, disappearing into the sewage.
Soon only the ropes that would pull him to safety in case of emergency were visible.
Derouen's gloved hands reached through the murky waters, searching for tactile landmarks, as he found his bearings and went about his job: inspecting the nine-foot-wide propellers that push sewage through Anne Arundel County's Patuxent Water Reclamation Facility.
Just another day at work for the 32-year-old Millersville resident.
Derouen earns his keep diving into cooling ponds for nuclear reactors and storage lagoons for industrial sludge.
The county Department of Utilities hired him last August to inspect the plumbing at the bottom of an oxidation ditch at the Crofton treatment plant where sewage is dissolved by bacteria.
Either a pipe had broken or something had fouled the air ports that feed the bacteria with necessary oxygen, said Rich Bowen, project manager for the Department of Utilities.
The county had no other way of knowing how extensive the damage was without draining the polluted water from the ditch. Draining the ditch would have taken two weeks and would have been a violation of the Patuxent plant's operating permit, which only allows emptying during the cold months between November and May, Bowen said. Violations could cost up to $10,000 per day, Bowen said.
"It's much more economically feasible to look at the pipes without draining it," said Derouen, a native of Brockton, Mass.
Derouen, who served 10 of his 13 years in the U.S. Navy as a diver, moved to Anne Arundel County when he was posted at the Annapolis Naval Station. He left the Navy and began commercial diving in 1989.
Now, he travels the East Coast, plying his trade. One month, he's cleaning sediment screens in a cooling pond for a nuclear reactor in Florida. The next, he's measuring the depth of sludge at the bottom of a storage lagoon operated by a Western Maryland paper manufacturer.
"I've been in some pretty corrosive stuff," said Derouen, who last week was inspecting the bulkhead around a waterfront hotel in the highly polluted Boston harbor. "But it's not like I'm subjecting part of my body to it. It's a completely sealed, dry suit. It's like a space suit."
Still, Derouen takes precautions. The week before he dove into the Patuxent pond, he spent $800 on immunizations. That many shots at once can hurt in more ways than one, Derouen said.
"My family was having a picnic that Friday," Derouen recalled. "I had the shots that morning. Driving home the next day, I hit the Jersey Turnpike with fever sweats."
He also spent several hours practicing for his dive in a dry oxidation ditch at the county's Broadneck Water Reclamation Facility.
"We told him the things he should feel for and their location in the ditch," said Bill Henderson, president of Trident Engineering, which coordinated the dive. "He's been in as bad or worse situations. You'd be amazed at what these divers get into."
Derouen eventually found several cracked pipes. Bowen estimated the cost of repairs, which began in November, at $100,000. The county paid Derouen $2,500.
"Would you do it for that? I wouldn't," Bowen said. "Everybody has to make a living, I guess."
Derouen shrugs off the notion that there is anything unsettling about his job.
Then, tongue in cheek, Derouen asked, "You're not going to put all this into the newspaper, are you? I guess I won't be able to get any more dates."