The bottle of Diet Coke that sent a University worker to the hospital last month has tested positive for a foreign substance.

The test, conducted by the Massachusetts State Laboratories, revealed a substance chemically similar to diesel fuel--a finding that is consistent with reports by the employee, who said the bottle of Coke, purchased in Loker Commons, smelled like fuel.

"We did find hydrocarbons indicative of petroleum distillates in the Coke," said Erica Berl, the coordinator of the Food-Born Illness division of the Mass. Department of Health.

The lab also tested three sealed bottles produced at the same time in the Needham bottling plant as the contaminated bottle and did not find anything wrong with them.

Health officials have not been able to determine the source of the contamination.

"We had a similar case of this in the past and it was [machine] lubricants," Berl said. "So one of our inspectors went out to the plant and he brought back a couple of grease samples which didn't match [those found in the contaminated Coke]. He couldn't find anything else wrong at the plant."

Yet despite the discovery of an fuel-like substance, Coca-Cola stands by its own tests, which did not find anything abnormal.

"We got the results back and we were able to determine that there was no problem with the drink," said Robert Lanz, Coca-Cola's vice-president of public affairs.

Coca-Cola officials would not comment on the results of the state laboratory test or on the potential cause of the contamination, citing legal reasons.

"The consumer who consumed this product has representation with an attorney and we will not comment," said Harriet Tolby of Coca-Cola.

In February, Lanz expressed concern about the likelihood of a single bottle being contaminated.

"We bottle 1,000 sodas a minute so affecting one particular bottle would be borderline impossible," Lanz said.

Another unsolved mystery is a discrepancy in the number of bottles impounded by the Harvard University Police Department (HUPD).

"When the officers went to the scene they secured the tainted bottle, and then they secured the remaining drinks in the machine," said HUPD Chief of Staff Kevin Regan.

A recent recount of the bottles resulted in 14 fewer than the original count, he said.

Regan said HUPD was analyzing why the counts did not match, but downplayed concerns.

"We have no reason to believe that it is anything more than an accounting error," he said.

The bottles, and all other impounded items, were kept in a property locker in the police station. Regan declined comment as to who has access to the locker.