Two-semi crash involving hazardous materials snarls traffic on I-84

Hazardous tank sustained serious damage in Friday semi crash on Interstate 84 west of Arlington. Photo courtesy Gilliam County Sheriff’s Office

The Dalles, Ore., Dec. 14, 2025 — A two-semi crash involving a hazardous materials tanker shut down traffic on Interstate 84 for nearly seven hours Friday afternoon west of Arlington, according to the Gilliam County Sheriff’s Office.

The crash was reported at approximately 12:50 p.m. on Friday, Dec. 12, near milepost 115, about 22 miles west of Arlington. Frontier Regional 9-1-1 received the initial report.

Investigators determined that a tanker semi hauling hazardous materials had just completed a required break period and was merging back onto the interstate to continue westbound. As the tanker increased speed in the slow travel lane, it was rear-ended by another semi, reportedly causing the collision.

The tanker was hauling a material identified as UN 3266, which designates a “corrosive liquid, basic, inorganic, not otherwise specified.” The material is classified as a Class 8 corrosive substance and is marked by placards indicating it can cause severe skin burns or damage to other materials if released.

The impact disabled the tanker trailer and caused significant structural damage, forcing it to block the slow lane. However, officials said the tanker’s hull remained intact and successfully and thankfully contained all of the hazardous material.

This semi rear ended the semi hauling hazardous materials on Interstate 84 west of Arlington. Photo courtesy Gilliam County Sheriff’s Office

The second semi reportedly lost its steer tires and crashed into the concrete median, pushing barriers into the eastbound travel lanes. That truck ruptured its fuel tank, spilling an estimated 100 gallons of diesel fuel.

Impact from the semi hitting the concrete median pushded the structures into the east bound lane. Photo courtesy Gilliam County Sheriff’s Office

Due to the hazardous materials involvement and fuel spill, additional emergency resources were requested, including assistance from neighboring fire agencies. Traffic on I-84 in the area was impacted from approximately 12:50 p.m. until 7:40 p.m.

Agencies assisting at the scene included Frontier Regional 9-1-1, North Gilliam Rural Fire Protection District, North Gilliam Medic Ambulance, the Sherman County Sheriff’s Office, Oregon State Police, Umatilla County Fire District No. 1, the Oregon Department of Transportation, and Purdy’s Towing & Transport.

Oregon State Police served as the lead investigative agency. Photographs of the incident were provided by Oregon State Police.