Morgan Hill officials are wondering if the Olin Corporation will
be held fully accountable for the mess it made in South County’s
groundwater basin. The road-flares manufacturer submitted a report
to the Central Coast Regional Water Quality Control Board last week
saying they are done with the investigation stage of their
perchlorate cleanup efforts, but the city doesn’t think Olin should
be let off the hook just yet.
Morgan Hill officials are wondering if the Olin Corporation will be held fully accountable for the mess it made in South County’s groundwater basin. The road-flares manufacturer submitted a report to the Central Coast Regional Water Quality Control Board last week saying they are done with the investigation stage of their perchlorate cleanup efforts, but the city doesn’t think Olin should be let off the hook just yet.
In the report, labeled a “characterization update,” Olin claims they are done identifying areas of the Llagas groundwater basin contaminated with harmful chemicals released from its facility formerly located at 425 Tennant Ave. from 1956 to 1995, explained Hector Hernandez of the RWQCB.
Hernandez said thus far, the board has been satisfied with Olin’s characterization, or identification efforts in the shallow and intermediate levels of the basin. However, they have differed with Olin on their characterization of the deep aquifer. He said staff will continue to review the update Olin submitted Feb. 2, after which they will determine if they agree.
But Morgan Hill Public Works Director Jim Ashcraft said Olin has yet to characterize a contaminated area in the basin that is heading towards the city’s northeast wells. He said for several years Olin has acknowledged that this plume of water is contaminated, but they do not feel their facility was the source of the contamination.
As part of their agreement to clean up the perchlorate that leached into the ground from their site, Olin has been required to submit periodic reports and updates on their characterization and cleanup efforts. Ashcraft said the city regularly objects to Olin’s updates as they have always failed to take responsibility for the perchlorate that is closest to the wells that serve Morgan Hill residents.
“They’re saying, ‘The characterization is done and we’re not doing anymore,’ ” Ashcraft said. “We don’t think that’s correct. The battle here is us telling them they’re not done with characterization, because the outer limits of the plume are not identified yet.”
He said while the water board is reviewing Olin’s latest update, so will the consultant hired by the city who studies local perchlorate contamination issues and has concluded in the past that Olin is responsible for the northeast perchlorate plume.
Hernandez explained that even if the water board staff agree with Olin’s report, the company would not be relieved of other aspects related to the groundwater’s cleanup, a complicated process involving pumping water from the aquifer, removing the harmful chemicals, and inserting it back into the ground. Olin is required to continue the long-term cleanup efforts until the perchlorate it allowed to leach into the water is at background or non-detectable levels.
In another area of the contaminated aquifer, closer to San Martin, the water board determined last month that Olin has removed enough perchlorate to reduce their periodic monitoring from bi-monthly to twice-per-year monitoring. Olin routinely requests to reduce its monitoring requirements on some affected wells in South County, and to be allowed to stop providing replacement bottled water for some wells.
Perchlorate is a chemical that affects the normal function of the thyroid gland if consumed by humans. Water that contains more than six parts per billion perchlorate is considered unsafe to drink and to cook with. Some of the wells in South County initially found to be contaminated in 2001 contained up to 50 parts per billion.
Hernandez also said the board is awaiting a more in-depth study to identify the sources of perchlorate north of the Tennant Avenue site and in the vicinity of the city’s municipal wells. He said there are numerous potential sources in that area in addition to Olin, including mushroom farms and nurseries.
Since about 2003, the city has treated the water from its contaminated wells before distributing it to customers. Ashcraft has said Olin should be required to help the city pay for that treatment, which is currently funded by the customers who are billed a 10 percent surcharge on their monthly water bills.
Phone messages left for Olin Corporation were not returned by press time.
Sylvia Hamilton of the San Martin Perchlorate Community Advisory Group said more than 1,000 wells were found to be contaminated by the Olin site when the problem was first identified. She said over the last eight years or so Olin has adhered to all the water board’s requirements, but the cleanup will continue for a long time.
“When all this started, our philosophy was we wanted to clean it up so future generations don’t have to deal with it,” Hamilton said. “And we’ve been very fortunate because Olin took responsibility for this.”
