A refinery near Denver sent plumes of orange and black smoke into the air Friday after a power failure shut the plant down, leading authorities to tell people within a 1.5 mile radius of the Suncor Energy, Inc. plant to remain indoors.
The company said the plumes, seen from downtown Denver, were "visible emissions" from the refinery in Commerce City which spokeswoman Nicole Fisher described as being from an uncombusted hydrocarbon. However, the Denver Fire Capt. Greg Pixley said Suncor notified authorities that it was releasing sulfur dioxide, a gas created by the burning of sulfur.
The executive director of the Colorado Department of Public Health and Environment, Dr. Larry Wolk, said officials don't know enough yet about what was in the smoke to determine if it was hazardous. However, he said authorities are reassured that the release was brief and doesn't appear to pose any immediate threat to people nearby.
Suncor will submit a report to the department about the cause of the malfunction and the emissions, he said.
The Environmental Protection Agency says short-term exposure to sulfur dioxide can harm the human respiratory system and make breathing difficult, especially the young, the elderly and those with asthma.
Fisher said Suncor is monitoring the air around the 98,000-barrel-a-day refinery, which produces gasoline, diesel fuel and asphalt.
Nearby Interstate 270 was temporarily shut down as firefighters responded to the refinery.
The power outage occurred around noon and the smoke dissipated by mid-afternoon.