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Radiation poisoning case highlights security concerns

By James M. Wahl

It seemed like a freak accident - a researcher exposed to a small amount of the radioactive tracer phosphorus-32 - until investigators from the Nuclear Regulatory Commission determined that it was a deliberate act.

On Aug. 14 postdoctoral researcher Yuqing Li, working at MIT's Center for Cancer Research, ingested a drop-sized amount of P-32. The Radiation Protection Office found that Li's intake was no more than 579 microcuries of radioactive material, which is within the 600 microcurie acceptable limit for single-event and annual exposure to the chemical.

Since the amount was under the limit, it was not enough immediate physical discomfort. As a result, it wasn't until five days later, in a routine self-examination using a Geiger counter, that Li determined he had been exposed to radiation.

Li was subsequently examined by the Medical Department and Environmental Medical Services and, according to the News Office, he suffered no ill effects.

The poisoning triggered an immediate inquiry by the Institute's Radiation Protection Office, the Campus Police, and investigators from the U.S. Nuclear Regulatory Commission. In mid-October the Institute confirmed that the NRC was investigating a radiation poisoning.

The Boston Globe, Washington Post, and National Public Radio, among others, reported on the incident - in part because of the poisoning's similarity to a case that occurred six weeks before Li's at the National Institutes of Health. In both cases, medical researchers of Chinese background were contaminated with similar doses of the same chemical.

The NRC concluded its investigation on December 8. In a 130-page report, investigators said the incident was "most likely" the result of "a deliberate act by a knowledgeable person."

Because there was no abnormal traces of radioactivity in the lab, which would be expected after accidental spilling of radioactive materials, the report concluded that someone put the P-32 in Li's food or drink, which was kept in a nearby room.

Security breaches found

The agency's report also criticized the Center for Cancer Research and the Radiation Protection Office for lax security, pointing out that the lab door could be propped open and the freezer containing the radioactive materials was unlocked.

Many of these violations went unnoticed by Radiation Protection Office auditors, who visit only during normal business hours, said Radiation Protection Officer Frances X. Masse.

In an effort to resolve such security lapses, the Radiation Protection Office tightened the enforcement of existing Institute policy, which is based on federal regulations on the use of radioactive materials, Masse said.

Specifically, the protection office is taking steps to ensure that potentially hazardous radioactive material is kept securely locked and under direct surveillance at all times, Masse said. Laboratory workers now are required to lock refrigerators and storage containers in addition to access points to areas where radioactive materials are used, he said.

Case unresolved

No legal action has been filed against MIT, but the case remains under investigation. Among the key issues unresolved are who committed the poisoning and why.

Li declined an interview with The Tech, citing health reasons. But the Globe reported that a source familiar with the case said that Li believes another worker may have been responsible for the assault.

Criminal investigators have conducted numerous interviews, but do not have any suspects, said Deputy Director of the NRC Division of Radiation Safety and Safeguards Susan Frant Shankman in a Boston Herald article. She said the person responsible for the crime could face federal charges.

"We have always believed that people who work with radioactive isotopes are knowledgeable, that they are using them as a tool to advance science," Shankman said. "I'm at a loss for why somebody would choose to use them in a deliberate, malicious way."