SIOUX CITY, Iowa (KCAU) — UPDATE: A stretch of U.S. Highway 20 east of Sioux City has reopened to traffic.

The eastbound lane near the Gordon Drive interchange closed for several hours after a semi truck hauling hay bales caught on fire. Traffic was rerouted onto Highway 75 North.

Fire crews from Lawton, Bronson, Moville, and Sergeant Bluff responded after several burning bales fell from the semi, igniting the ditch. The heavy smoke caused near zero visibility.

The cause of the semi starting on fire is not known at this time.

PREVIOUS: The left lane on U.S. 20 westbound is blocked due to a vehicle on fire.

According to the Iowa DOT, between County Road K42 and Exit 4: IA 12; US 75; Gordon Drive, the left lane is blocked due to a vehicle on fire.

At 6:16 p.m., the Iowa DOT said due to the fire, there is a two minute delay on U.S. 20 eastbound.

Motorists should seek an alternative route.

This is a developing story. KCAU 9 has a crew on the scene. We’ll provide further updates as we learn more.