BEIJING — Leaked oil from a ruptured pipeline in an eastern Chinese port city caught fire and exploded Friday, killing at least 22 people and injuring several others while contaminating the nearby sea.

The pipeline owned by China's largest oil refiner, Sinopec, ruptured early Friday and leaked for about 15 minutes onto a city street in Qingdao and into the sea before it was shut off. Hours later, as workers cleaned up the spill, the oil caught fire and exploded in two locations, the city government said.

Authorities ruled out the possibility of terrorism, but the incident remained under investigation, it said.

Calls to Sinopec's headquarters in Beijing were not immediately answered.

One explosion occurred at a city intersection, and photos posted online showed shattered concrete slabs and human bodies on the ground.

The Qingdao Environmental Protection Bureau said barriers had been set up to contain the oil as it spread into the sea, but that a mixture of gas and oil from a storm sewer exploded and caught fire over the sea.

More than 3,000 square meters (32,000 square feet) of sea surface was contaminated, the city government said.

Authorities said the oil had seeped into underground utility pipes, but assured the public that the blasts did not affect any petrochemical plant or military facilities in the seaside district and that air quality remained good after the disaster.

Members of the Chinese public have become increasingly vocal about safety and environmental risks that come with oil pipeline projects.