Finding Is New Hurdle for Ahmanson Ranch

Perchlorate, a potentially hazardous chemical, has been found in the ground water at Ahmanson Ranch, a discovery that could present yet another hurdle to the already besieged proposal to build a mini-city of 3,050 homes west of the San Fernando Valley.

Ventura County officials found significant levels of perchlorate, which has been linked to thyroid problems, in a 550-foot-deep sample of Ahmanson Ranch ground water supplies earlier this year. The amount, 28 micrograms per liter, was seven times higher than new safety guidelines that the state has set for drinking water while it develops more detailed regulations. The perchlorate was found at the historic Ahmanson Ranch site in an area that would be set aside as open space.

Though government officials have not yet pinpointed the source of the contamination, signs point to possible migration from the nearby Santa Susana Field Laboratory, where rocket and nuclear reactor testing has taken place since World War II. The former Rocketdyne facility, now owned by Boeing, has left widespread chemical and radiation contamination, including high levels of perchlorate, which was often used to make rocket fuel. Earlier this year, officials detected perchlorate in water wells in Simi Valley, which also shares a border with the rocket testing ground.

Ventura County officials, who are conducting an environmental review of the proposed development, are still trying to determine whether the perchlorate could have come from the rocket site, and whether it is a threat to humans or wildlife.

“We’re still exploring the issue,” said Ventura County senior planner Dennis Hawkins. “If it is the result of an underground connection to Rocketdyne, other contaminants should show up. And we are mystified as to why they have not.”

State water quality officials, who were unaware until recently of the perchlorate contamination at Ahmanson Ranch, told the county in writing last week that they will need more time to review the potential consequences before weighing in. Water officials are concerned that the plans to pump water at the 2,800-acre Ahmanson site to use at a golf course and for construction purposes could pull contaminated ground water toward the development. That, they fear, could impede efforts to clean up the Santa Susana site by causing plumes of underground pollution to spread outward from the testing facility.

“It’s important to note that the well was never intended to be a drinking water well,” said Melinda Becker of the water board, “but this could be a sign of the spreading of the contaminant plume. Perchlorate tends to lead the plume.”

Environmental activists and others opposed to the development have seized on the perchlorate findings, and are asking Ventura County officials to slow down the process of approving it. A county panel is scheduled to discuss the environmental review today, and possibly make a final recommendation to the county Board of Supervisors.

“The county should not be rushing to approve this project given this extraordinary new finding that a contaminant found in high concentrations at the Santa Susana property has now been found in ground water at Ahmanson,” said Daniel Hirsch, president of the environmental group Bridge the Gap. “If perchlorate has migrated from Rocketdyne, there is the potential for a lot of other contaminants to migrate, including radioactivity, and that should not be swept under the rug.”

Perchlorate is the latest in a series of setbacks for Ahmanson owner Washington Mutual, which wants to build a $2-billion golf course community on the ranch of majestic oaks and sweeping grasslands. It is the largest remaining privately owned parcel of open space separating the San Fernando Valley and Ventura County.

In 1999, the rare California red-legged frog and San Fernando Valley spine flower were discovered on the property, delaying construction. Los Angeles County politicians, including Los Angeles Mayor James K. Hahn, have spoken out against the project, decrying its traffic impacts on their side of the county line.

Earlier this month, former Vice President Al Gore called Ventura County Supervisor John K. Flynn and pleaded with him to block a procedural move to speed up review of the development.