Excessive levels of mercury vapor forced some Naval Academy employees to move to temporary offices Friday, according to academy officials.

About 30 of the 170 people who work in Halligan Hall, an administrative building, had to be relocated pending more investigation, said academy spokesman Cmdr. Joe Carpenter.

No actual mercury was found, Cmdr. Carpenter said, but the vapor was detected in the north end of the building, on the first floor.

Cmdr. Carpenter said the recorded levels ranged from 1,000 to 4,500 nanograms per cubic meter of air.

The Centers for Disease Control sets the maximum safe level at 1,000...