The cause of the fire is not yet known.
Fire crews were called to 33733 King Rd. just before 2:30 a.m.
On arrival, they found heavy smoke and flames coming from one of the units. Firefighters quickly attacked the flames and brought them under control.
The fire was contained to one unit, which contained art supplies, with smoke and water damage to the two units on either side.
According to witnesses, what appeared to be an incendiary device was found at the scene.
Nine fire vehicles and 34 firefighters were dispatched to the scene. Total damage is estimated at $30,000.