An insurance company for the troubled Community Savings & Loan says that because of a secretary's clerical error, it could be found liable for tens of millions of dollars in damages in the event the thrift's top officials are found to have acted improperly.

American Casualty Co., which provides liability insurance to Community's directors and officers, filed suit in federal court here last week in an attempt to undo the purported error and limit its liability in the growing number of lawsuits against Community and its top officials.

The Bethesda-based thrift was taken over by the state of Maryland on Sept. 5, and depositors have been unable to withdraw funds.

"It's a mere clerical error," said Raymond J. Jast, a Chicago lawyer representing American Casualty's parent company, CNA Insurance Companies. "Apparently it was a case where something like 'O231' was put in [on an insurance form] where '0232' should have been put in."

Community officials disagree, asserting that the policy says what it's supposed to.

The dispute dates to February 1984, when Community was buying liability insurance to cover its officials in case they were sued in connection with their corporate duties. According to American Casualty's suit, Community agreed in writing that the insurance firm should insure all 11 directors and officers for a total of $5 million in damages.

But when the insurance company prepared the documents, somebody made a "clerical error," and granted the 11 thrift officials coverage of $5 million each, the suit said. That amounts to a difference of $50 million in potential exposure.

That could be costly for the Reading, Pa.-based American Casualty, since Community, affiliated companies such as its EPIC real estate arm, and thrift officials have been hit with at least five lawsuits filed in various courts by EPIC's real estate partners and Community depositors. One suit filed by two local banks asks for $100 million in damages for alleged misdeeds.

Community's officials say that there was no mistake, and that they intended all along to buy the $5 million coverage per officer, according to court documents.

Under a plan recently agreed to by Maryland officials and some EPIC creditors, the thrift's officials could be sued only by the state. But some creditors have refused to agree to that plan.