RIO VISTA, Calif. -- State Highway 12 in unincorporated Solano County reopened Saturday evening after a four-alarm fire broke out in a nearby field and burned multiple structures, according to the California Highway Patrol.

The blaze was reported shortly after 5 p.m. in an open field on the north side of state Highway 12 just west of Summerset Drive near Rio Vista, CHP Officer Tom Stewart said.

The fire was not declared under control as of 7:15 p.m.

No injuries have been reported, the sheriff's office said.

The CHP issued a Sig-alert at 5:58 p.m., which was canceled at 6:58 p.m. The fire was near the westbound side of the highway but traffic on both the westbound and eastbound directions was affected, Stewart said.