The House upholstery shop has been temporarily shut down after a potentially harmful level of black mold was discovered there.

Officials suspect the mold, specifically identified last week as the airborne fungi penicillium and aspergillus, was caused by water leakage first reported to the Architect of the Capitol by the Chief Administrative Officer18 months ago.

It is unclear when the substance began to grow in the shop, which is located in a subbasement of the Rayburn House Office Building and overseen by the CAO.

Upholstery workers noticed a musky odor lurking in the shop following heavy rainstorms in July, which caused a significant amount of water to leak from the roof.

“We just figured with the water coming in, it was only a matter of time before we’d have a problem,” upholsterer Dave Peebler said.

The AOC, which serves as the facilities manager for the Congressional campus, has been working on a major project to replace the waterproofing system on the roofs of the House underground parking garages located near the shop, said spokeswoman Eva Malecki. The repairs are nearing completion and should correct the water leaks, Malecki added.

In the meantime, actions will be taken to make repairs to the upholstery shop, including scrubbing down the area, Malecki said.

“Air sampling will be conducted by safety specialists over the next few days to determine if any health hazards exist,” she said. “Additional actions will be taken as appropriate.”

But the damage has caused the ire of CAO Dan Beard, who first saw the mold during a visit to the shop two weeks ago.

Beard recalled: “I looked at the wall, and I saw the streaks, and said, ‘What the hell is that?’”

Beard ordered samples of the substance be sent to a lab for analysis. When specialists found that some of those samples showed 10 times the allowable level of penicillium and aspergillus, Beard immediately ordered the six upholstery employees be moved out of the shop.

“It’s a potential health hazard,” Beard said. “I don’t know how big of a health hazard, but I’m not going to take any chances.”

Aside from removing the employees, Beard also sent a letter to acting Architect of the Capitol Stephen Ayers detailing the closure. Copies of the letter, which was not made public, also were sent to House leadership officials and the House Appropriations and House Administration committees.

And Beard contacted the Office of Compliance, seeking guidance on the mold issue. OOC acting Executive Director Tamara Chrisler confirmed that an inspections process has begun at the site.

Penicillium and aspergillus are a common, natural mold, but subspecies can have some “nasty effects,” CAO Safety Coordinator Mike Garrott said.

The substance can cause respiratory issues, particularly in people with a damaged immune system, Garrott said.

“In a contained environment, it’s not good for you,” he added.

At the upholstery shop on Wednesday, Garrott pointed out where the largest sample of mold had been found. That mold had found a perfect place to grow, located underneath a cabinet that only recently had been removed during a remodeling project.

The remodel efforts, which already have seen some of the facility’s cabinets removed and replaced, allowed workers to spot the substance. But the discovery of the mold also has stalled the remodel project — the floor can’t be replaced until the mold problem is taken care of, for example.

“It’s probably good it happened when it happened, because everything would have been moved in,” Peebler noted.

Mold requires three things to grow, Garrott said: the proper medium, standing water and time.

“This was the perfect collision of things,” he added. “It doesn’t look like much. In fact, in the beginning, we thought it was rust.”

The six-person upholstery team should complete its move to nearby offices by Friday, said Carol Swan, the acting director of textiles.

Upholsterers are in charge of upkeep and repair on a range of furniture used in the House, from couches in Member offices to chairs used in committee rooms.

Much of the furniture requires historic preservation. Swan pointed to a black couch that had not been reupholstered since 1957.

Beard noted that because the employees are being moved to other offices, the time it takes to complete projects likely will increase.

“We’ll reduce productivity for awhile,” he said.