Last week, Massachusetts Hall was closed to students and faculty due to a flea infestation and subsequent treatment. When Housekeeping discovered the pests on Saturday, a local pest control service performed a treatment later in the day.

Associate Director of Facilities Operations Jeff Tuttle said that the building was treated again on Monday because the life cycle of the flea makes it difficult to knock them all out at once.

Pest control used a localized application of aerosol and foam to wipe out the fleas, as opposed to a highly intrusive "bomb" that is sometimes used to kill pests.

"That's a last ditch effort," said Tuttle. The substance used by pest control, though mild to humans, was strong enough to kill the fleas.

"Even in its wet state, at its most it's an irritant," said Tuttle. By halting the reproduction of the fleas, it kills the fleas within a day or two.

After inspections on Tuesday confirmed that the building was free of fleas, Massachusetts Hall was reopened on Wednesday morning.