A colony of rats is wreaking havoc at Duluth's Congdon Park Elementary, prompting district officials to close the school and its playground for the summer.

Since the unwelcome discovery, pest control workers have trapped about five rodents per day near the foundation and drainage system underneath the school gym, said district facilities manager Dave Spooner.

"We're working to remove them before they can get into the building itself," Spooner said in a prepared statement. "Having the building and grounds unoccupied will allow us the flexibility to take steps necessary to make that happen."

The school is located at 3116 E. Superior St., not far from Glensheen mansion.

Food sources that might attract the vermin have been removed.

The school's composting bin likely played a role. "They enter into — I don't want to call it a rat buffet — but they had plenty of food, shelter and water and took up residence," Spooner told the Duluth News Tribune.

Pesticide bait boxes — called the "least toxic method" — have been laid near burrow entrances located in the hillside at the back of the building to help eradicate the infestation. District officials said those efforts are compliant with state Department of Health and Environmental Protection Agency guidelines.

Signs will be posted around the property to inform neighbors the traps are being used.

Students were released for summer vacation last week, but administrators had remained on the grounds. Scheduled enrichment activities will move to Ordean-East Middle School.