The second floor of Washington’s wastewater treatment plant is vulnerable to significant damage if the hydrogen sulfide in the plant becomes explosive.

Because of the threat, the city has been advised by its insurance provider to upgrade and explosion-proof the equipment and electrical devices at the plant. The Board of Public Works agreed Wednesday morning to seek bids for the project.

Engineers have estimated the work would cost $360,000.

Water/Wastewater Superintendent Kevin Quaethem said the upgrades have been discussed for some time. He said there have been several meetings until, finally, Jacobs Engineering came up with a design and bid specs.

Quaethem said the city’s engineering department has signed off on the plans and everything would be up to code.

The plans call for a complete overhaul of the second floor.

“All the equipment on the second floor — there’s controllers, there’s switches, there’s motors, there’s lights, there’s fire alarm systems — all that needs to be explosion-proofed,” Quaethem said.

The process of explosion proofing the facility is fairly simple.

“You take a regular outlet, and you modify it with a case where no gas and air can get in,” he said.

Board member Rob Vossbrink said he was “baffled” such action would have to be taken so soon after the facility opened.

“There were no issues when this wasn’t included in the original plans,” Vossbrink said.

Quaethem said the explosion-proof features should have probably been installed from day one. However, at some point during the construction someone said it didn’t need to be done.

“Somewhere along the design process, somebody said it didn’t need to be in,” Quaethem said. “Nobody is saying who did, nobody remembers who did it, but the bottom line is that if that had been in the plans when the plant was built it still would have been about the same cost to have it installed.”

Quaethem said the upgrades are needed in case a hydrogen sulfide accident happens. Hydrogen sulfide is produced during the treatment process at very low levels.

At the Washington plant, the numbers have been low and not caused a problem. If the hydrogen sulfide levels were to increase, the results would be explosive.

“As plants age, conditions change,” he said. “All it would take would be one time for the hydrogen sulfide levels to build up. If something would go wrong, it would be catastrophic.”

Quaethem said the cost estimate came in after the budget was made for the 2014-15 fiscal year, so the project wasn’t included. He said he has met with City Administrator Jim Briggs to discuss funding.

Quaethem said the city was confident it could pay for the project despite it not being in the budget.

“I feel we need to move ahead, just for the safety side of it,” Quaethem said. “Should it have been put in? It probably should have. Why wasn’t it? Nobody remembers who said what. The bottom line is, it does need to be done.”

Board President Kurt Voss said he agreed with Vossbrink that spending a significant amount of money on a building that just opened in 2009 doesn’t sit well with him. However, he said he understood the need for the upgrades.

“I don’t like it,” Voss said. “But at the same time, I’ve heard from engineers, I’ve heard our insurance people that it needs to be done. It’s what the code requires. I don’t want it on my hands that we knew about it, and didn’t do something to remedy the problem.”

The board voted unanimously to move forward with the project and start the bidding process.