Excerpt:

Some of the toxic contamination at Alameda Point is not the result of naval operations.

The soil beneath the runways became contaminated with polycyclic aromatic hydrocarbons (PAHs) before it ever became part of Alameda Point. The fill material used for creating this land mass was dredged from the Oakland Estuary primarily between 1936 and 1941 by means of a pumping system. It was contaminated by a coal gasification plant, which operated in Oakland about 100 years ago that disposed of waste into the waterway.

The Navy recently began cleaning up contaminated soil at five hot spots in the airplane runway. Cleanup Site 33, the area commonly referred to as the wildlife refuge, encompasses the southern end of the main north-south runway and adjacent tarmac, and is near the least tern nesting site and a wetland area.