Rayford Cofer, 63, a master steamfitter, was killed when the line ruptured while he was working in the mechanical room of the Levine Science Research Center on Research Drive shortly before 3 p.m., according to an Internet statement posted by the university Wednesday evening.

The building houses classrooms, laboratory space and offices where more than 100 Duke employees were working at the time of the accident. No other injuries were reported.

The cause of the rupture has not been determined by Durham fire officials.

Cofer's death was announced by Kemel Dawkins, vice president for campus services, who said, "Our thoughts and prayers are with [Cofer's] family."

The Duke news release said Cofer, a Franklinton resident who began working with Duke's Facilities Management Department in 2001, was known by his co-workers as one of the "go-to guys" who overcame obstacles on difficult assignments. He was twice honored with one of Duke's top employee awards for meritorious service.

"It's horrible," said John Burness, Duke senior vice president for public affairs and government relations. "It's worse, obviously, for the family. All of us are in a state of shock."

Investigators were still determining who was doing what when the incident occurred, Dawkins said. The building has no record of previous problems, and the steam lines are inspected "constantly," he said.

Whether construction of utility lines in front of the building had anything to do with the accident was still being determined, he said. He said Cofer was alone in the room when the incident occurred.

Dawkins said Duke officials also were investigating to determine whether any research was lost or damaged in the incident. "Initial assessments show that no [lab] animals were injured."

Graduate student Yoni Adigum was working on a paper in a first-floor classroom when he felt rumbling under his feet. He said he and other students in the room jumped. Adigum quickly got out of the room when the rumbling continued.

"Everyone looked at each other," said Adigum, 29, who is from Houston. "We knew it was something big."

Christina Powers, 23, a graduate student from Atlanta, said she initially thought that the vibration came from outside the building and that the subsequent noise was like rushing air or water.

"It's more scary after the fact," she said while looking at about a dozen emergency vehicles parked outside the building.

Students and employees later were escorted back into the building long enough to retrieve their belongings, but it remained closed late Wednesday. Significant amounts of water was found in the basement afterward, and the water has to be tested for chemicals before it can be pumped, Dawkins said.

The research center, behind Duke Hospital, is considered one of the largest research facilities in the country. Opened in 1994, the building is home to the Nicholas School of the Environment and houses space for pharmacology and cancer biology, cell and molecular biology, neuroscience research and engineering. The 341,000-square-foot building is split into four sections, connected by a series of hallways and stairways.