Cleanup continues at I-15 spill site

By: EDMOND JACOBY - Staff Writer | Friday, August 6, 2004 11:05 PM PDT ∞

ESCONDIDO ---- Nearly all of the contamination that resulted from a hazardous chemical spill July 21 on Interstate 15 just north of Deer Springs Road has been cleaned up, officials say, but it still sits in containers beside the freeway and an adjacent road, Champagne Boulevard.

Meanwhile, water running down a manmade concrete streambed that lies in the watershed of the San Luis Rey River continues to be diverted just above the point where the dangerous industrial waste poured out of a storm drain into the culvert.

The diverted water is being pumped uphill to Champagne Boulevard, where it runs downhill along the roadway's curb for more than 100 yards before it tumbles back into the concrete and natural stone ditch.

The diversion is to keep the water from contacting the contaminated portion of the concrete basin.

The spill occurred during rush hour in the northbound lanes of I-15 when acids in a stainless steel tanker ate through the vehicle's walls and began spraying following traffic. Eventually, the entire 3,000-gallon load was lost onto the freeway and its east shoulder, from which it ran into a storm drain and gushed into the streambed.

The incident closed the freeway in both directions for almost 15 hours, creating havoc for homebound commuters.

The spill contained both acids and heavy metals. According to cleanup personnel monitoring the pump used for the water diversion, the acids were quickly neutralized. The ongoing concern is because of chromium that leached into the concrete and has resisted easy removal, they said.

The concrete stream bed has been stained red-brown by iron in the mixture.

Tests conducted Thursday will determine whether additional cleanup is needed in the streambed.

"They've literally power-washed the cement and vacuumed out the (residue)," said Brad Long, an environmental health specialist for the San Diego County Department of Environmental Health. Rinsate is the runoff from the cleaning process.

"They sample the (residue) to determine whether more is still needed, and to the best of my understanding there still are cleanup efforts going on because more is needed to complete it to the level desired," Long said.

"All of the spilled liquid has been removed, as well as any contaminated soils and vegetation," he said. "Now we're looking to address trace contamination in the concrete basin itself."

The contaminated materials stored in large bins on site, mostly soils and brush, cannot be moved until a sample of the material stored in them has been tested by the facility to which it will be taken, Long said. The facility's tests are needed to determine how best to dispose of the material.

Once those tests are complete, the stored materials will be hauled off, but cleanup may continue in the stream bed if chromium levels remain unacceptably high. As long as that cleanup is ongoing, the pumping equipment will remain in place to divert stream water around the contaminated area, Long said.

"Encapsulation is always an option," Long said. Encapsulation refers to the entombment of the contaminated section of culvert with additional concrete poured over and around it.

"But we are not currently considering that," he said. "We will focus on localized areas of contamination to get it out of there."

Some thought had been given to breaking up the concrete and hauling it away, but it is between two- and six-feet thick and penetration by the chromium is very shallow, he said.

"I'd be very skeptical if anything made it down to the native soil" beneath the concrete, he said.

Tests by a laboratory to determine whether the chemical in the tanker truck matched the chemical described on the shipper's manifest may have been completed, Long said, but if they have he is not aware of the results.

Contact staff writer Edmond Jacoby at (760) 739-6675 or ejacoby@nctimes.com.