A fire in one unit of an eight-unit apartment complex caused about $30,000 damage Wednesday, but firefighters prevented the blaze from spreading into adjoining apartments.

The fire started when an 11-year-old boy plugged in a portable radio just before noon. The boy - out of school on spring break - told fire officials he saw a large spark and smoke when he plugged the radio in. The spark started his bedroom on fire.Salt Lake County Fire Lt. Dennis Steadman said the boy grabbed a portable phone, ran outside and dialed 911. Salt Lake County firefighters arrived at the Stajduhar residence, 1261 E. Shadow Ridge Drive (7180 South) #11C, within a few minutes.

"It was heavily involved in fire and flames were coming out of the bedroom window," explained Steadman.

Fire crews were able to extinguish the blaze in less than 10 minutes. The lieutenant praised the firefighters for their "exceptional efforts." The blaze was seconds away from reaching into the common attic that would have spread the flames to other apartments.

"This was a beautiful knockdown," he said. "I wish we would have had a cameraman here. We would have used this fire for training films."

The fire was apparently so intense that it melted the smoke detectors. "Once the fire burned through the bedroom door, the temperatures in the other rooms were probably in excess of 1,000 degrees ceiling temperature," Steadman said.

Although the fire was mostly contained to the boy's bedroom, the rest of the apartment suffered extensive smoke and heat damage.