A New Call to Clean Perchlorate

Morgan Hill officials say new evidence proves them right and
contradicts Olin’s claim
San Martin – Morgan Hill leaders say new evidence proves that the Olin Corp. polluted the city’s groundwater and they’ve renewed calls for the company to begin cleaning it up.

According to City Manager Ed Tewes, a report released last week by Olin contradicts the company’s assertions that its former road flare factory is not the source of the city’s perchlorate contamination that flows north.

While the company continues to deny that its responsible for the city’s pollution, Olin for the first time has allowed that it’s possible. Olin has accepted responsibility for a 9.5-mile perchlorate plume flowing south and east of the Tenant Avenue site and is under a state order to clean it.

Tewes said Monday that the time has passed for the Central Coast Regional Water Resources Control Board to issue a similar order for the so-called northeast flow that has contaminated city wells that serve 6,000 residents and hundreds of businesses. Morgan Hill residents pay a 15 percent surcharge to cover the city’s cost of removing the perchlorate, a sodium known to disrupt thyroid function.

“The board appears to be using two different standards,” Tewes said. “Two years ago the board cited Olin as the discharger [to the south] on no greater scientific evidence. The only difference is, Olin didn’t resist.”

Since the pollution was revealed in February 2003, Olin has provided bottled water to residents in the most-contaminated areas south of the site, and in February, the water board ordered the company to present a final cleanup plan for the southern plume by June 2006.

But Olin has resisted responsibility for the northern flow, citing their own studies that show the groundwater beneath its factory does not flow to the north.

Company consultants reaffirmed that position last week, but in their latest analysis of South County groundwater activity, they conceded for the first time the theoretical possibility of a northern flow. The company’s most detailed analysis to date of groundwater at various depths revealed some northern movement.

Michael Taraszki, a hydrogeologist with Olin Consultant MACTEC Engineering and Consulting Inc., said it’s conceivable that perchlorate-laced water flowed north at some point in the past, though he doesn’t believe it did.

“This is an emerging story,” Taraszki said. “There’s nothing that would stop that from happening, but it’s not occurring. All we can say for certain is what’s happening today. Historically, it all becomes a little more conjectural.”

Morgan Hill officials point to some historical data to support their argument, most notably a 1916 U.S. Geological Survey map that shows groundwater flowing north under what is now Tenant Avenue. And Tewes said Olin’s suggestions that the city’s perchlorate is from another source or naturally occurring are “unreasonable.”

“Our arguments starts with common sense, but is bolstered with the science such as it is,” Tewes said. “The standard in the law is whether there’s a reasonable basis for declaring a responsible party and we want a responsible party identified.”

David Athey, who’s managing the cleanup effort for the water board, said his agency will continue to evaluate the evidence before deciding to order Olin to clean north of the site. Athey has pressed the company to perform a forensic analysis of the northeast flow, a relatively new procedure that may pinpoint the source of contamination.

Olin resisted that effort, and to keep the issue out of court, the water board agreed to let the Santa Clara Valley Water District perform the analysis as part of broader attempt to learn the history of perchlorate contamination throughout the groundwater subbasin. The district will begin the analysis in the coming months and may know the source of the northeast flow in about a year.

Morgan Hill Mayor Dennis Kennedy, though, called the forensic analysis a “red herring” that focuses attention away from the real problem – protecting the city’s water.

“The real solution is to put into place a [cleanup order] for the entire contaminated basin, including the northeast flow,” Kennedy said.

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