Photo may have been deleted

Fire officials in Massachusetts are warning TikTok users not to participate in a dangerous viral challenge that causes fires when pennies are placed on iPhone chargers.

The viral trend is responsible for setting classrooms on fire at two Massachusetts schools this week.

The Plymouth fire department issued letters to Plymouth North High School students and parents warning them to stop putting pennies on the exposed prongs of iPhone chargers.

Photo may have been deleted

Photos: Plymouth Fire Department

Firefighters say the exposed prongs coming in contact with a copper penny causes an arc of electricity from electrical outlets.

According to a teacher, two students plugged iPhone chargers into outlets and placed a penny between the partially exposed prongs of the charger and the outlet, resulting in sparks and flames.

"It's almost like an explosion," said Plymouth Fire Chief Edward Bradley. "The electricity propels the charger and the coin - the coin is molten metal at this point," Bradley told WHDH TV.

"It does not take much to be electrocuted fatally just by an outlet in a wall socket," he explained.

Amherst Fire Department Assistant Chief Jeff Olmstead said the viral challenge could cause thousands of dollars in damage to the electrical system "if they have to pull those wires back to a circuit breaker. The damage to the person, electrocution causing burns or death or starting clothes on fire or items nearby," he told Western Mass News.

Olmstead said pranksters will be charged with felony arson and property damage.

"Although they are younger, they will face fees, fines and probation and no one wants to see them have a felony or conviction on a record."