With a few weeks to go before children return to their classrooms, the Sitka School District believes it has flushed out the rodent problem at Baranof Elementary School.
The source of the rats' entry? An open toilet drain in a six-foot square bathroom that was walled off during last year's remodeling project.
"I think we've found the problem," said School District Superintendent Steve Bradshaw.
"We're now in the process of getting into the room, getting it cleaned up, and cementing over the hole. We think we have the problem solved."
"I feel very surely, very strongly that's where the rats were coming in and out of the building," agreed Hunter Horvath, school district director of maintenance.
Last April, the district reported finding rats and signs of rats at Baranof. Maintenance workers spent considerable time plugging all visible holes and setting traps to capture the pests, the superintendent said.
District officials believed the problem was solved. But as teachers began returning over the summer to prepare their classrooms, they started seeing signs that the rats were back, Bradshaw said.
City Engineer Rich Riggs said the source was discovered inadvertently last week by the city Deputy Fire Marshal Kelli Cropper, who was performing a regular fire and life safety inspection. She noted that a section of wall did not go completely to the ceiling, and told the school district maintenance staff to address the problem.
Horvath said when his staff looked into the enclosed space, they discovered rat feces and the unsealed dry sewer pipe. They investigated further by opening the wall. Horvath believes the rodents entered Baranof through the pipe, then crawled up construction debris that had been left in the space to enter the main part of the building.
He said an open toilet drain can also allow sewer gases to vent back into the building, and noted that a teacher had noticed a smell coming from that area from time to time.
He said that at the building department's suggestion, George Erickson, senior facilities operator for the wastewater treatment department, tested the area for carbon monoxide, oxygen percentage, hydrogen sulfide and explosive gases such as methane.
"They were all in the normal range," Erickson said.
Horvath said the workers will clean out the area and seal the pipe opening. The area will then be converted into a storage space.
Another big job will be rigorously sanitizing the area, he added.