A radioactive spill two weeks ago in a Medical School building has raised concerns about Harvard's compliance with safety procedures for radioactive substances.

The spill, which evacuated two Medical School buildings, resulted from improper procedures for collecting radioactive materials, according to Robert Hallisey, director of the Massachusetts Office of Radiation Protection.

"It was a fairly significant activity that should not have happened," Hallisey said. "There were obvious places where people got lax."

Federal inspectors with the Nuclear Regulatory Commission (NRC) plan to review Harvard's use and disposal of radioactive materials later this year in their annual surprise inspection visit.

But the spill of the radioisotope phosphorus-32 was not serious enough to warrant an immediate inspection of the site, said John Kinneman, an NRC inspector.

"It was clear that Harvard knew what was going on and they were addressing the cleaning of the spill," Kinneman said. "It didn't rise to a level that required corrective action."

Hallisey said the shoes of eight people were found contaminated with radioactive material, but no one is known to have been contaminated directly. Contamination with phosphorus-32 is dangerous only if exposed directly to skin.

Hallisey, who led the state Nuclear Incident Advisory Team that first searched the buildings for contamination, said the spill was due to a sequence of three acts of improper waste collection.

"There were a number of things that happened that caused the problem," Kinneman said. "We are going to make our own observations to see why that happened."

Kinneman said that Harvard, which is licensedby the NRC to use phosphorus-32, is required tomaintain information on the spill for the NRC toreview during its annual visit.

"It was a minor matter after the fact, but itcould have been a worse situation," Hallisey said