A fine of $3,750 was set for a Class III (midrange) violation by the NRC for an incident Sept. 11 when a graduate student researcher failed to detect the presence of radioactive phosphorus (P-32), a few drops of which he had spilled on the floor in front of his lab bench. He then tracked it out into the hallway on the soles of his shoes.
The spill occurred on a Friday in a Medical Science Research Building 7th-floor lab and was unknowingly spread around the building over the weekend on the shoes of other staff members. The isotope was detected on Monday, Sept. 14, and a rapid containment and cleanup effort was mounted by U-M Radiation Safety staff aided by NRC staff.
Although nearly all the P-32 remained in the lab and on the 7th floor of Medical Science Research Building I, trace amounts were found in some staff cars and in five homes. All were successfully cleaned.
Mark Driscoll, U-M radiation safety officer, noted that there was no health hazard since a very tiny amount of lowlevel isotope with a short half-life of 14 days was involved.
He added, however, that there was a significant regulatory concern. "The spill should not have gone undetected and the P-32 should not have been tracked out of the building."
This was the focus of the NRC violation notice: that the researcher should not have allowed the isotope to spill and that he failed to check his shoes with a radiation counter, as required, before leaving the laboratory thus allowing it to spread.
The notice also called for better training and supervision of staff in the lab as well as more intensive audits of radiation-handling labs to certify that all involved staff understand regulations and follow them.
The NRC identified three other violations of its requirements that were not directly associated with the contamination incident: 1) two researchers in the laboratory not wearing radiation monitors on their hands, 2) failure to specifically approve the laboratory for the use of phosphorus-32, and 3) leaving a package containing a small quantity of P-32 in a hallway on Aug. 11.
In the August incident, the package was inadvertently removed from the hallway with normal trash and disposed of. Because of the small quantity of P-32 and its packaging, the materials would not have represented a significant safety hazard when buried with normal trash.
The U-M already has taken action to warn its researchers about the need to exactly follow NRC-approved regulations and is stepping up its efforts to continually educate laboratory staff on requirements for handling isotopes. The University will report back to the NRC on all corrective actions called for in the violation notice.