MADISON -- A spill of a commercial grade flooring material in an elevator shaft has been determined to be the cause of a noxious odor that led to the precautionary evacuation of dozens of residents from an assisted living facility.

Forty-one residents in all were taken to surrounding facilities or sent home with family on Monday after a strong odor was reported inside the Lantern Assisted Living facility on Hubbard Road. There was not a fire.

The odor was isolated to the back of the building near the elevator. Emergency personnel along with facility management made the decision to evacuate residents.

An environmental clean-up firm was called in to clean up the spill.

All residents were returned to the facility Tuesday afternoon.  Air test levels performed prior to the residents' return came back clean according to facility administrators.