Olin Corp. can seek full indemnification for its costs at five environmental sites for the year 1970, says a federal appeals court in the latest ruling in a long-running environmental case.

San Francisco-based OneBeacon America Insurance Co. was appealing two judgments that awarded Clayton, Missouri-bead Olin, a chemical manufacturing company, $80 million in indemnification costs, according to the ruling by the 2nd U.S. Circuit Court of Appeals in New York in Olin Corp. v. OneBeacon et al.

The latest opinion in the complex environmental litigation — which has involved dozens of insurers over the years, and was originally filed in 1983— focuses on five Olin manufacturing sites in McIntosh, Alabama; Fields Brook/Ashtabula, Ohio; Augusta, Georgia; Rochester, New York; and Bridgeport, New Jersey.

OneBeacon had issued Olin three excess umbrella insurance policies for the period of 1970 through 1972 that had attachment points of $300,000, according to the ruling.

While the policies provided up to $20 million in coverage in excess of $300,000 per occurrence, because effective Jan. 1, 1972, they included a pollution exclusion, only the period of Jan. 1, 1970-Dec. 31, 1970 is the subject of the ruling.

The unanimous three-judge appeals court, in ruling on a case on appeal from the U.S. District Court in New York, disagreed with One Beacon and held Olin’s underlying policies had been exhausted and OneBeacon’s policies have attached.

“Olin may pursue OneBeacon for full indemnification for its costs at these sites up to the policy limits for the 1970 year,” said the ruling. The ruling vacates and remands the District Court’s ruling, which was based on an earlier appeals court ruling, for a new damages judgment because of a more recent ruling on the methodology involved.

Among the other issues considered in the opinion is the effect of Olin’s settlements with its prior insurers, which were London market insurers, and on OneBeacon’s obligations.

“While we agree with OneBeacon that its limits of liability should be reduced by amounts paid to settle claims with respect to the five manufacturing sites at issue here, there is no basis on the record for which we might calculate that amount,” said the ruling.

“If, after appropriate discovery, OneBeacon can do so, then the limits of liability on the policies it issued to Olin should be reduced accordingly,” said the ruling.  “With these principles in mind, we remand to the District Court for further proceedings on this issue.”