BOEING TO HALT WATER CLEANUP; LOWER POLLUTION REDUCES NEED AT FIRM'S CANOGA PARK PLANT.

Byline: David R. Baker and Lisa Mascaro Daily News Staff Writers

After a seven-year cleanup effort, Boeing officials and state regulators said Thursday they have agreed to stop cleansing groundwater under the Canoga Park plant because the pollution has been greatly reduced.

State inspectors will continue to monitor the groundwater to see whether levels of chemicals continue to drop without more treatment. If not, Boeing Co. could be required to resume the cleanup.

``We think Mother Nature will finish the job they started,'' said Jim Ross, senior engineer with the state Regional Water Quality Control Board, Los Angeles Region. ``If we're wrong, we'll revisit this in a year.''

Although he emphasized that the polluted water has not contaminated drinking-water wells, Ross said the board would continue looking for any signs that the chemicals are seeping from the site at Canoga Avenue and Vanowen Street.

If they are, or if contamination levels rise again, the board could require a new treatment program. ``We don't want it going off the site and impacting surface water,'' Ross said. ``That's our primary concern.''

Boeing bought the plant along with the rest of Rockwell International's Rocketdyne Division in 1996, assuming its cleanup responsibilities.

Since 1991, the board has required the owner of the parcel to run an extensive operation that involves pulling the contaminated water out of the ground, cleaning it and flushing it down the Los Angeles River. More than 500 million gallons have been treated and 8,000 tons of pollutants have been removed.

The chemical culprits involved - trichloroethylene and perchloroethylene - have tainted the water table under several parts of the San Fernando Valley for years. The two are heavy-duty solvents that once were widely used in the area's aerospace industry but now are suspected of causing cancer.

Although the two chemicals are still present in some test wells on the site, others show no measurable contamination, said John Geroch, associate engineering geologist with the water board. On evidence of declining levels, Boeing stopped pumping and treating the water in April.

``There comes a point where you can keep pumping, but what's the point?'' Geroch said. ``The concentrations (of contaminants) are to a point where they may no longer be a threat to water quality.''

Ross said further pumping would not significantly change the current levels of contamination.

Since Boeing has stopped releasing treated water into the river, the company no longer needs the water-discharge permit it had received from the regional board. Board members are scheduled to vote Monday on whether to rescind the permit.

A Boeing spokesman declined to comment, and Boeing officials involved in the cleanup effort could not be reached for comment Thursday.

Geroch said the company should be commended for an effective cleanup operation. ``It's important to realize they have done a good job,'' he said.

Although he had not extensively reviewed the end of the pumping at the site, a member of a Rocketdyne watchdog group said Thursday that the water-monitoring program appeared sound.

``It looks like they're doing the right thing,'' said Joe Lyou with Committee to Bridge the Gap.