As concerns over conditions in the Capitol’s utility tunnels continue to hang like a black cloud over the Architect of the Capitol’s office, a steam pipe explosion in downtown New York last week left some on Capitol Hill wondering: Could a similar incident happen here?

While the Office of Compliance downplayed the likelihood of such an occurrence Tuesday, the man who was responsible for maintaining Congress’ steam pipes for the past eight years said it is a distinct possibility.

Last Wednesday’s explosion in Manhattan left one woman dead of a heart attack, more than two dozen injured and a massive crater in a busy downtown street. Since the explosion, city health officials have raised concerns about possible asbestos exposure and an extensive cleanup effort has been under way. While an exact cause for the explosion has yet to be determined, initial reports indicated that the incident was the result of water collecting in the steam pipe.

The combination of cold water and steam pressurized at up to 200 pounds per square inch can create an explosive combination. And if the water has nowhere to go, “it can become like a projectile,” said John Thayer, a 23-year veteran of Capitol Hill’s utility tunnel system who also is the former supervisor of the AOC’s tunnel maintenance team.

Thayer, who left the AOC’s office last month after settling a complaint against management, said Capitol Hill very well could be in store for an explosion similar to the one that happened in New York because the Architect’s office has neglected its utility tunnel system — which houses steam and chilled water pipes — for more than a decade.

“They’ve been so lax in doing anything about the tunnels that unless they take it seriously and start doing assessments, based on what I’ve seen it’s a good possibility,” Thayer said.

But Office of Compliance General Counsel Pete Eveleth said Tuesday that “we’re well aware of that incident in New York. … We can understand how people would ask if that could happen here because of the information out there about our tunnels. It’s not an unnatural question, but the danger is assuming that the same conditions exist.”

While some similarities do exist (for instance, both steam lines operate at 150 to 200 psi), the New York line that exploded was about twice the size of the Capitol Hill lines, and it is buried while the lines providing steam and chilled water on Capitol Hill are contained within tunnels or trenches.

“It depends on the history of the system, how well it’s maintained or not maintained, what corrosion may exist, how they are constructed, whether there has been excavation in the area,” Eveleth said. “It is apples and oranges to some degree.”

“As a general proposition I don’t see [a steam pipe explosion] occurring [on Capitol Hill], but that’s why we want to make sure that they do have good preventative maintenance plans,” he said.

The AOC’s failure to fix several health and safety issues in the tunnel system led the Office of Compliance to file a historic complaint against the agency early last year. That complaint not only brought about increased Congressional scrutiny on the tunnels but also resulted in a settlement agreement signed in May. According to OOC officials, that agreement requires the AOC to abate the many health and safety hazards in the tunnels, including falling concrete and loose asbestos, and requires the agency to develop a comprehensive preventative maintenance plan for Capitol Hill’s steam-pipe system.

“It’s not just enough to fix a particular hazard. We have said in the settlement agreement that no hazard will be considered abated unless we are convinced they have a preventative maintenance program,” Eveleth said.

He pointed out that if the AOC had put in effect a sufficient preventative maintenance plan in the first place, many of the issues included in the 2006 complaint would not have been a concern.

Terry Dorn, the Government Accountability Office’s director of physical infrastructure issues, said his agency never has done a specific study on the possibility of steam pipe explosions on Capitol Hill, but in studying the tunnel issues last year his agency did find that “not only does the AOC need to be concerned with the condition of the tunnels but also the condition of the pipes.”

A spokeswoman for the AOC said Tuesday that the agency “performs regular inspections and maintenance on the steam lines, and continues to do so.”

“In addition, we initiated a comprehensive, multiphased inspection of the tunnel system in 2006, which focused on issues such as structural conditions, life-safety and operational infrastructure,” AOC spokeswoman Eva Malecki added. “These inspections provided the foundation for the development and implementation of the AOC’s ongoing utility tunnel improvement program.”

But Thayer said the OOC settlement, which gives the AOC five years to fix all the tunnel hazards, is too little too late, especially when the Architect would prefer to continue to put Band-Aids on a damaged system rather than invest the $500 million he estimates it would take to overhaul the system completely.

Thayer, who will be testifying about tunnel issues next week before a House Appropriations subcommittee, said one example of the continued problems are the steam leaks in the pipes under the West Front of the Capitol. Rather than fixing the leaks, which are not only dangerous but also kill the grass, the AOC prefers to resod the West Front on an annual basis, he said.

Thayer added that he specifically raised concerns with the OOC in the past year about the quality of the steam pipes that were installed to feed the new Capitol Visitor Center.

Thayer and more than half of his 10-man tunnel team left the Architect’s office last month after a settlement was signed in a retaliation complaint they filed with the OOC against the AOC for harassment they say they received after stepping forward last year to tell Congress about the poor conditions of the tunnels.

He said now that he and most of his experienced crew are gone, he worries about the contractors the AOC since has brought in to maintain the steam and chilled water lines.

“I don’t want to sit at home and read that someone got killed because of this,” he said.