Technicians work to bring the Faculty of Arts and Sciences' IT systems back online in the basement of the Science Center on Friday.

A fire in the Science Center's machine room brought down a significant share of the computing services for the Faculty of Arts and Sciences (FAS) on Friday.

The fire caused a "catastrophic failure of the power supply" that was responsible for disruptions of several key Harvard Web sites and services, according to a notice posted on the FAS Web site.

Among the affected sites and services are the my.harvard portal, FAS Web sites, and FAS e-mail accounts.

According to notices posted in the Science Center, the services have been down since at least 6 p.m., though some services were back up around 10 p.m.

Russel S. May, FAS Computing Services' director of systems, infrastructure, architecture, and standards, said that FAS technicians have not yet identified the "definitive root cause" of the fire.

"The vendors are in there evaluating the situation," May said at the Science Center Friday night. "We're just focusing on the problem now."

May, who declined to say who the vendors were, said that the power supply would be back up by 10 p.m., but that it was not immediately clear how long it would take for the services to return.

"It depends on how the systems respond," May said.

FAS spokesman Robert Mitchell did not respond to a request for comment last night.

—Clifford M. Marks contributed to the reporting of this story.

—Check The Crimson for further updates on the situation as details become known.