LIVERMORE, CA. -- The first Department of Energy national lab location to complete environmental clean-up is Sandia National Laboratories/California, the lab announced today.

Officials considered clean-up complete once the San Francisco Bay Regional Water Quality Control Board approved ending a pilot project that had hastened natural degradation of a subterranean fuel oil spill.

Sandia's environmental remediation team said recent studies showed the spill posed no risk. The site will be monitored for two years. Then Sandia will meet with the board to determine whether monitoring indicates that final closure of the site is appropriate.

Overall, Sandia/California had 23 sites -- mostly very small -- to clean up or characterize. The three more sizeable sites were the fuel oil spill, a Navy landfill and the Trudell Auto Repair Service Station at the southeast corner of East Avenue and Vasco Road. Sandia acquired the service station property and cleaned up oil-contaminated soil there in 1988.

The Navy landfill consisted primarily of construction debris dumped as a matter of convenience on a hillside off the south perimeter road when Lawrence Livermore National Laboratory expanded in its early days, before Sandia acquired the site in 1960. The chunks of concrete may have included parts of an old runway from the days LLNL was a Naval air base during WWII. The debris just needed to be removed and any potential erosion controlled by planting native seeds. Groundwater monitoring never indicated any real contamination.

Of potential contaminants, very low concentrations of diesel and carbon tetrachloride were found in part-per-billion levels in monitoring wells, well below regulated amounts. Sandia conducted a very intense groundwater flow study to characterize the hill and found that because a fault block is uplifted, water does not flow from the hill toward the main complex of buildings on site, or beyond the lab property. Six monitoring wells were sampled quarterly for at least 10 years prior to closure of this hillside site in 1992. One well remains for monitoring purposes.

Breakdown of contaminants in the fuel oil spill was hastened in the 1990s with a bioremediation project that injected nutrients, salt and oxygen underground to encourage soil microbes to decompose the oil. The underground leak occurred in 1975 when a worker installing a grounding rod nicked a buried line from a fuel oil tank. The oil was stored for back-up generators during the energy crisis, and never used. Some 59,000 gallons of oil formed a plume that extended down 100 feet from the surface.

Following a wet season, the water table rose and reached the bottom of the plume that was adsorbed onto clay particles in the soil. As a result, the bioremediation project was started in 1995. In the meantime, studies conducted for the state of California demonstrated that old diesel spills are not as threatening as once thought, and pose no serious risk if protected. In fact, the study found, if left alone long enough, underground diesel spills naturally decompose.

The plume is monitored by a ring of wells, and will be tested for two years to ensure that natural decomposition is continuing. Risks assessments showed no impact above Clean Water Act standards, said Dick Fate, Sandia's Environmental Restoration manager for project closure, and the regional water quality control board determined in July 1999 that the bioremediation project appeared to have run its course.

In New Mexico, Fate added, remediation of about 200 sites, begun in 1993, is almost complete. A unique streamlined regulatory process entails preparing a study, that is submitted for approval, and then an implementation plan. Streamlining cut the time for regulatory approvals from five -10 years down to just a few months, and nearly halved the estimated cost from $625 million to $340 million.

Media contact:
Nancy Garcia, negarci@sandia.gov, (925) 294-2932

Technical contacts:
Jim Bartel, jjbarte@sandia.gov, (925) 294-2956