The disaster began at 3:25 p.m. PDT (22:25 UTC) when an underground gasoline pipeline crossing Whatcom and Hanna Creeks ruptured.

The incident was caused by a series of errors and malfunctions involving Olympic Pipeline, compounded by an excavator's failure to call in and locate the damaged section.

[3] The disaster began as Olympic Pipeline was transporting gasoline from Cherry Point Refinery to terminals in Seattle and Portland, Oregon.

[2][4] When the Bellingham Fire Department arrived, massive amounts of gasoline had turned the creek pink, and the fumes were overwhelming.

[7] Two children, Wade King and Stephen Tsiorvas, both ten years old, were playing near the creek confluence during the explosion.

Both survived the blast, but sustained severe burns, dying the next day at Harborview Medical Center in Seattle.

Olympic Pipeline had failed to properly train employees and had to contend with a faulty computer SCADA system and pressure relief valve.

The companies pleaded guilty to several of the charges, leading to a $112 million settlement, a record at the time.

[2] The Whatcom Falls Park in 2020 describes much of the area around the creek as "sensitive due to hazardous trees and for forest recovery from 1999 pipeline explosion.