Crude oil, natural gas liquids involved in Elk City explosion

Addington said the explosion was in the business's yard and described the material inside a “frac tank” apparently involved in the incident as “highly explosive.” “Frac tank” is industry slang for a portable steel storage tank, said Jim Gipson, a spokesman for the energy company.

In this case, the tanks were being used to store crude oil and natural gas liquids that caught fire during the explosion.

According to its website, Hodges Trucking is an oil-field and heavy haul transportation company and an affiliate of Chesapeake Energy Corporation. Elk City is about 100 miles west of Oklahoma City.

One injured person was taken by air to Oklahoma City for treatment, Addington said. Another victim was taken to Great Plains Medical Center in Elk City.

A man was treated and released at the medical center, said Monte Deramus, a Great Plains hospital administrator.

Addington did not have information on the victims' names or conditions.

No firefighters were injured in the blaze, which remains under investigation, Addington said.

Bob Jarvis, manager of corporate communications for Chesapeake Oilfield Services, a subsidiary of Chesapeake Energy Corporation, said by email Sunday the investigation to determine a cause of the fire is ongoing. The person being treated in Oklahoma City is expected to be released in the next day or two, he said.

This story has been updated to reflect that the materials that caught fire were crude oil and natural gas liquids.