University police and other agencies are investigating the Aug. 26 poisonings, which were revealed in an internal memo to medical school faculty last week. The memo identified the substance involved as sodium azide, a common preservative used in school labs, but did not indicate whether officials believed the laced coffee to be accidental or intentional.
"I always thought it was a deliberate substance added to the coffee," said Matteo Iannacone, a postdoctoral fellow.
"It was too strange for me to be an accident," he told the Associated Press in an interview on Monday.
Iannacone said he immediately noticed a "weird" taste after sipping an espresso he poured from a coffee machine in an eighth-floor lounge near his research lab. After taking a second sip to make sure he wasn't imagining the foul taste, he began feeling dizziness and a rapid heartbeat, but said the symptoms cleared rapidly.
Two of the researchers who drank coffee earlier in the day had fainted, but officials did not immediately connect their illnesses to the coffee machine, Iannacone said.
Iannacone said he was taken by ambulance to nearby Brigham and Women's Hospital, where he was treated and released. Doctors could find nothing wrong, he said.
Iannacone said he was informed privately last week by university officials of the results of toxicology tests. Daniel G. Ennis, executive dean for administration, and Richard M. Shea, associate dean for physical planning and facilities, later sent the internal memo to Harvard Medical School faculty.
"As the investigation continues, we are being prudent and taking additional precautionary measures to ensure the well being of our community," the memo said.
Among the steps being taken was installation of additional security cameras in its buildings and "strengthening security systems that manage access to the laboratories during both normal business hours and off hours," according to the memo.
Iannacone said he was unaware of any threats against the school and did not know of any controversial research that might have made the facility or any of its researchers potential targets.
"I have no idea who might have done this thing," he said. To me it doesn't look like a joke, obviously, because we were not far from a lethal dose."
The machine was a single-serve coffee maker with a water reserve that is filled manually, not the type that is plugged directly into the building's water supply.
While surprised that it took nearly two months for the investigation to reveal the cause of the illnesses, Iannacone said he believes the university has done a thorough job.
"I am satisfied with the way they have answered questions," he said, adding that he agrees with improving security at the school.
David Cameron, a spokesman for Harvard Medical School, said a lot of thought went into how to communicate the incident and that officials decided not to make a school-wide announcement until definitive results were known.
"The toxicologists who were looking at this had to ... try to figure out what is the short list of agents that could have done this and then conduct tests for those particular agents. So it took roughly this long to finally come up with a definitive test to say it was sodium azide," Cameron said.
Once the results were known, the people who had ingested the chemical were notified individually.
Harvard police were looking into "every possible, conceivable option as to how this could have occurred," said Cameron, who also indicated he was unaware of any threats against the school.
The federal Occupational Safety and Health Administration said it was looking into the incident to determine if there were any violations of health or safety standards in the workplace.
"We were notified last week about the possibility of poison being involved," said Ted Fitzgerald, a spokesman for OSHA's Boston office. He said the agency's probe could take up to six months.
"There had been a courtesy call from the school about people taking ill back in August," he said.
The Boston Public Health Commission also was assisting in the investigation, but a spokeswoman for the city agency said it did not have authority to regulate the Harvard labs.