A radioactive spill last Wednesday at the Medical School closed a research building for more than 10 hours and forced workers to evacuate the site.

The Environmental Health and Safety Office ordered Building D-2 closed from late afternoon Wednesday until 10 a.m. Thursday morning. Officials said there was no serious damage.

"The cause of the physical properties of P-32 and the location of the traces resulted in no radiation exposure," said Suzanne Rauffenbart, associate dean for public affairs at the Medical School.

A small amount of liquid phosphorous-32, a radioactive isotope of the element, leaked from a transport cart on route to a protective waste room. A researcher discovered traces of the radioactive isotope while conducting daily standard safety procedures.

The short-lived isotope, which is used as a tracer in medical research, left invisible spots that were detected with a Geiger counter. A clean-up crew found traces on the floor and in the elevator.

Several employees also found the material on the soles of their shoes. Safety officials continued checks of workers' shoes through Friday morn- ing.

Officials said most of the waste was removedsuccessfully with a cleaning fluid. Some of thewaste, however, seeped through cracks in the floortiles. Those tiles that could not be removed werecovered with plywood, which neutralizes theisotope.

Researchers and faculty members met yesterdayto discuss precautionary measures that couldprevent future spills. Results of an investigationwill be released in two weeks.

Although Rauffenbart said everything is nowback to normal, some medical students are stillworried.

"We still check the soles of our shoes with theGeiger counter," said third-year medical studentRussell R. Reid. "It is a big concern for everyonethat we can unknowingly bring the radioactivesubstance into our home.