Updated:CARY, N.C. (AP)
als in Cary are trying to determine how five tons of dried human waste caught fire and burned.
The News & Observer of Raleigh reported the city sells the dried feces as high-quality fertilizer.
The fire was discovered in a city processing site late Wednesday morning. Workers used nitrogen dioxide to try to smother the flames. But the fire smoked for about four hours.
City officials say they will be able to reprocess the burned waste.
Cary spokeswoman Carrie Roman says the fire posed no danger to the public. She also said there was no bad smell.
The city generates about 6 million tons of the fertilizer each year.
Officials still don't know how the fire started.