RAWLINS -- The Sinclair Refinery and the Wyoming Department of Environmental Quality have been working since early September to address complaints from local residents about odors coming from the facility in Carbon County.

DEQ inspectors pinpointed two sources that they and John Pfeffer, the refinery's environmental health and safety manager, agree are likely the cause of the odors.

But they say there's still work to be done to confirm there are no other odor sources at the refinery or elsewhere in Sinclair or Rawlins.

Bob Gill, a DEQ Air Quality Division official, said the primary odor source at the refinery is a storage tank used for hydrocarbons.

Pfeffer said two hydrocarbon materials that contributed to the smell have been diverted to other areas of the refinery. In addition, damaged seals on the tank will be repaired, he said.

"All that together, we believe, is the problem with this tank," Pfeffer said.

The other source of odors at the refinery is a project north of the facility to clean up soil that was contaminated some 30 or more years ago, Pfeffer said.

Disturbing the soil has released odors, he said.

Pfeffer said a possible way to control the soil odor is to apply a type of foam as the project proceeds.

That would help lock down odors coming from the soil, Pfeffer said.

"It also has an odor-masking agent in it -- like an air freshener, for lack of a better term," he said.

Gill said he expects the mitigation to be successful and to be completed by week's end with the exception of cleaning excess material from the tank, which could take up to 30 days.