At 4:55 p.m., the gasoline vapors exploded, creating a river of fire from the rupture site near the Whatcom Falls Water Treatment Station, one and a half miles down the creek, to Interstate-5. The massive fireball sent a plume of smoke 30,000 feet into the air, visible from Anacortes to Vancouver B. C. Dense black smoke caused the closure of Interstate-5 for more than an hour. Fearing the fire would continue flowing down the creek into downtown Bellingham, police officers began evacuating businesses. Gasoline migrated into the city’s sewer system, and the vapors were at explosive levels for an hour. The U. S. Coast Guard, concerned the fuel could ignite dock pilings and vessels, closed Bellingham Bay for a one-mile radius from the mouth of Whatcom Creek.