Insufficient information to pin northeast contamination on
Olin
A regional water board says it does not have enough information to pin perchlorate contamination in northeast Morgan Hill on the Olin Corporation, a road flare manufacturer ordered to clean up the potentially harmful substance from groundwater south of the city.
“There are a lot of questions, a lot of complexities, and at this time we don’t believe we have sufficient information to assign responsibility (for the northeast area),” said Hector Hernandez, an engineer overseeing clean-up efforts for the Central Coast Regional Water Quality Control Board.
The agency elaborated its reasoning in a 22-page report sent to Morgan Hill City Hall earlier this week. In it, the water board argues that numerous sources could be responsible for the perchlorate found in the Nordstrom Park well north of Tennant Avenue. In addition to the factory Olin operated from 1955 to 1987, the report states that perchlorate –Â a sodium known to cause thyroid dysfunction in large enough quantities – could have come from fertilizer, groundwater from nearby ponds and chlorine bleach from city wells and local mushroom farms.
The report also points out that perchlorate concentrations at the well have fallen below the public health goal since 2003, when perchlorate was first discovered in South Valley.
The agency said it would not order Olin to conduct additional studies to determine the source of pollution. Instead, officials will await a forensic analysis of groundwater by the Santa Clara Valley Water District. That analysis is due in summer 2007.
The report caps a year-long wait by Morgan Hill officials, who asked the regional water board to investigate Olin’s responsibility for the northeast contamination at the beginning of 2005.
“It’s been a letter long coming and it’s pretty extensive, but I think it’s fair to say we’re disappointed,” Morgan Hill City Manager Ed Tewes said. “It seems to say that we the board of the regional water agency acknowledge that there is perchlorate north of Tennant Avenue, but we’re not sure they’re the discharger and we hope that some day, somebody else will figure it out.”
Tewes said he expected greater engagement from the agency and plans to voice his dismay at a May 12 water board meeting.
In the meantime, the city’s 36,000 residents will continue to pay a monthly surcharge on their water bills for perchlorate clean-up, while a thousand families south of Tennant Avenue receive free bottled water from Olin. The company, which spends $60,000 per month to supply the water, has accepted responsibility for the 9.5-mile perchlorate plume that stretches south through San Martin and east of Gilroy. But it has steadfastly denied responsibility for contamination to the north.
“I think that through the preponderance of evidence, the decision is clear – there is not one source of perchlorate in the area. There are multiple sources,” said Rick McClure, an Olin engineer and spokesman. “We thought that this was a decision appropriate some time ago. Olin has extended significant funding to investigate (the northeast) area and we never really thought we were responsible for that.”
In recent weeks, Olin has tried to shift some responsibility for the southern plume to mushroom farms, but McClure said the company will proceed with a clean-up plan due at the end of June.
In coming months, the regional water board will establish a baseline clean-up level for the southern plume that will determine how much remediation the company must perform. And in a little more than a year, the agency expects to have the forensic analysis of northeast contamination in hand.
