Colin A. Young, News Staff

The Marino Center was evacuated for more than an hour Friday morning after a small fire broke out in an underground transformer behind the building, according to fire officials.

Shortly before 11 a.m., firefighters were called to the corner of Forsyth Street and Speare Place, where an NStar employee working in a manhole had sprayed a chemical on the transformer.

“A worker was using a penetrating spray to loosen a bolt at an underground transformer,” Steve MacDonald, a Boston Fire Department spokesman said. “The spray flashed over with a flame, then self-extinguished.”

There were no injuries reported and because the transformer had been de-energized for routine maintenance, there was no loss of power, MacDonald said.

“The issue with the manhole set off the fire alarm in Marino … so the place was evacuated as a routine precaution,” university spokeswoman Renata Nyul said in an email to The News. “A short time later everyone returned and everything resumed as normal.”

A district chief said that the crews vented the manhole and checked the air quality with meters before clearing the scene.

The incident prompted a level II hazardous materials response from the fire department, which allows them access to additional apparatus and resources, a fire official said.

Northeastern officials did not immediately return calls seeking comment.