Crews were called out to the fire in the 1400 block of South Blount Street shortly before 7:15 p.m. Initial calls came from the Cargill, Inc. plant, but when firefighters arrived, they discovered the fire was across the street at S&H Trailer Rental.
Two mobile homes and a car were on fire at the vehicle storage center. About 50 firefighters took an hour and 15 minutes to put out the fire.
A preliminary investigation showed that the fire might have been intentionally set, fire officials said, but cautioned that they have only started to probe the cause and origin of the fire.
"There are reports of suspicious activity in the area," Raleigh Fire Department Division Chief Rusty Styons said. "However, it's so early. Our investigation has just begun."
Officials said the layout of the S&H Trailer Rental hampered firefighting efforts. Firefighters had to use a ladder truck, because it was the only way to get close enough to put out the flames.
"This area is completely shielded and blocked in by these trailers parked side by side all the way around," Styons said. Investigators will look at whether there were any fire-code violations at S&H Trailer.
Blount Street was closed during firefighting efforts on Friday night. Public officials advised motorists to avoid the area.
Early reports indicated that hazardous materials were on the site. Emergency crews brought in air-monitoring equipment, and tests revealed no contaminants, officials said.
Investigators stayed at the scene overnight to sift through the evidence.