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Radiation Ingestion Prompts Concerns

By A. Arif Husain
Associate News Editor

The recent irradiation of an MIT post-doctoral researcher has prompted the Radiation Protection Office to take steps that will tighten the enforcement of Institute safety regulations.

Yuqing Li reportedly ingested a small amount of the radioactive tracer phosphorus-32 while working at the Cancer Research Center in August ["Researcher Exposed to Above Normal Radiation Levels," Oct. 20].

While the quantity ingested was just under allowable levels, the rarity of such an incident has heightened concern about safety. An investigative team from the Nuclear Regulatory Commission suspected the P-32 may have been added maliciously to Li's food or drink, since no other traces of the substance were discovered in the laboratory where he works.

Several security breaches found

"All we are trying to do is to enforce the [existing] regulations," said Radiation Protection Officer Francis X. Masse. The most important goal in terms of safety is "general awareness more than anything else" and a focus on "common sense" kinds of oversights.

MIT's policy comes from federal regulations on the use of radioactive materials, Masse said.

Specifically, the Radiation Protection Office is attempting to ensure that potentially hazardous radioactive material is kept locked securely and under direct surveillance at all times, Masse said. Laboratory workers will be required to lock refrigerators and storage containers in addition to access points to areas where radioactive materials are used, he said.

In particular, efforts are being made to ensure that laboratories are secured during off hours, he said.

The NRC has reported evidence of security breaches such as doors left ajar on evenings and weekends. These violations went unnoticed by Radiation Protection Office auditors, who visit only during normal business hours, Masse said.

NRC continues its investigation

The Radiation Office has closed its investigation, but the NRC has dispatched an Incident Investigation Team to determine whether the incident was deliberate or accidental. The team was formed after initial information gathering suggested the poisoning may have been intentional.

Over the two months since the incident was reported, the Radiation Office has worked in conjunction with a physician from Harvard Medical School to determine the actual amount of radioactive material that Li ingested. Data gathered by the Radiation Office along with urine samples have been submitted to Oak Ridge National Laboratory and Lawrence Livermore National Laboratory for further analysis.

Masse said that he expects the data gathered by the Radiation Office to be proven accurate and properly measured by the outside laboratories.

Dose too small for effects

The Washington Post reported in an Oct. 26 article that a source with detailed knowledge of the case said Li has complained of "vomiting and aches and pains."

But according to Masse, Li did not suffer any symptoms from his radiation exposure. Instead, Masse believes that reports of minor discomfort resulted from Li's stress after the finding.

"[Li] has complained about aches and pains, but I would not think for a minute that has anything to do with radiation exposure," Masse said.

The allowable limits of radiation exposure were set so that no symptoms would result from levels within them, Masse said.

Li was found to have ingested 579 microcuries. The annual and single-event limit is 600.

Since Li was very close to the limit, he was advised to take time off for recuperation. He is not presently working in the laboratory.

Li declined an interview with The Tech, citing health reasons.