SALT LAKE CITY (AP) - Environmental advocates will try to persuade the Utah Supreme Court on Wednesday that the state's approval of expansion at the Tesoro oil refinery would add to northern Utah's air-quality woes.

SALT LAKE CITY (AP) Environmental advocates will try to persuade the Utah Supreme Court on Wednesday that the state's approval of expansion at the Tesoro oil refinery would add to northern Utah's air-quality woes.

The legal battle is the latest illustration of the intense scrutiny air quality issues receive in Utah. Doctors warn that the polluted air that sometimes gets trapped between two mountain ranges during inversions can cause lung problems and other health concerns.

At issue in Wednesday's hearing is the state's approval of expanded operations at the refinery.

Environmental groups challenged the decision, arguing the state require stricter emissions controls. State regulators stand behind the decision, arguing in court documents that Tesoro met all state and federal requirements.

The winter air pollution commonly exceeds federal clean-air limits in the Salt Lake City metro area.