Scrap Tyres Cause Environmental Disaster

In December 1994, a landslide damaged a road near Ilwaco, Washington. By the summer of 1995, engineers attempted a novel repair, using 2 to 6-inch shredded tire chips as lightweight filler instead of traditional soil and rocks. This approach aimed to solve both road repair needs and scrap tire disposal problems.

However, the project quickly encountered issues. Cracks began appearing in the road surface by December 1995, followed by significant heat venting in January 1996, with surface temperatures reaching 165°F. By March 1996, an oil-like substance, later identified as pyrolytic oil from rubber decomposition, seeped into the adjacent Baker Bay Coastal wetlands.

Approximately 300 to 400 gallons of this contaminant entered the intertidal areas, impacting about 300 to 350 square feet of shoreline and endangering local wildlife. Containment efforts were initiated, including barriers and absorbent materials, to control the spill. The exact cause of the heating remained uncertain, with possibilities including oxidation, humidity, and biological activity.

This incident, along with two other similar heating events involving shredded tires in Washington and one in Colorado during 1995, prompted federal authorities to act. In July 1997, the Federal Highway Administration released interim design guidelines to mitigate internal heat generation in tire fill projects, including regulations on tire thickness and minimizing moisture and air exposure.