Firefighters believe Saturday’s fire at a Tim Hortons in Arthur was caused by an electrical issue.

“An employee went back to the electrical room and she saw the smoke,” said David Guilbault, the fire chief for Wellington North. “She immediately called the fire department.”

Crews arrived at the coffee shop, on Highway 6 and Wellington Road 109, around 4 p.m.

Guilbault said the fire spread from the electrical room and across the ceiling into the dining area.

Everyone inside, 10 employees and 18 patrons, escaped unharmed.

Damage has been pegged at $1 million.

Officials say the fire is not being treated as suspicious.

The Ontario Fire Marshall is investigating.