Duluth School District leaders say they're making progress on ridding Congdon Elementary school grounds of its rat infestation.
Facilities manager Dave Spooner says, last week Guardian Pest Solutions put heavy-duty plastic boxes, containing poison around the outside of the school.
This week he says the investigation into their progress really begins.
Since the rats are expected to consume the poison, and die later in their burrows Spooner says it will be hard to produce a solid number of dispatched rats.
It's also hard to determine how long the operation will take.
But officials say they're hopeful the process won't cost the district more than $5,000.
Congdon Elementary School will be closed to the public this summer following the discovery of rats, Duluth School District officials said in a statement Wednesday.
The District said staff and a local pest control firm are working to clear the footing and foundation drainage system underneath the gym addition of a population of rats.
Pest control workers are currently trapping about five rats per day.
"We're working to remove them from the burrows created in the hillside and beneath the gym addition before they can get into the building itself," said Dave Spooner, ISD 709 Facilities Manager.
Spooner estimated there to be about 100-200 rats total. He said he's seen 75 rats for himself during the day.
Spooner says the planned methods to accomplish eradication are "fully compliant" with Minnesota Department of Health and Environmental Protection Agency guidelines.
Timestamps on pictures of the rats provided to KBJR 6 by the district suggest the rat infestation was first reported to district officials on May 18, while school was in session.
The district and the local pest control company started by removing any food sources that might attract the rats.
"Having the building and grounds unoccupied will allow us the flexibility to take steps necessary to make that happen. We appreciate everyone's support as we work to keep our school grounds healthy and safe."
According to Spooner they'll begin reducing the population with the least toxic method, which includes pesticide bait boxes set outside the footing and foundation drainage system and near the burrow entrances in the hillside.
Spooner says the district is communicating with Congdon neighbors, families and the public and will be posting signage to alert people that these boxes are being used.
KEY Zone and EXCEL programs are being moved to Ordean East Middle School.