Firefighters inside the Connelly School Credit: via Pete Piringer @mcfrspio on Twitter

The Connelly School of the Holy Child in Potomac is closed Tuesday after a small fire damaged a conference room Monday night.

The fire started around 10 p.m. and was caused by the “spontaneous combustion” of oily rags, according to county fire department spokesman Pete Piringer.

An automatic fire alarm brought firefighters to the scene at 9029 Bradley Blvd., according to Piringer. The fire caused less than $50,000 in damage and no one was injured, he said.

The school posted a notice on its website notifying families that it is closed, except to AP calculus students, who took an exam Tuesday morning.

“There are NO e-learning assignments due today,” the school wrote. “We will send out more information to families later in the afternoon.”

The Connelly School teaches about 300 students in grades six through 12 in two buildings on an approximately 10-acre campus. The fire occurred in the conference room of the school’s main building, according to the website.