Prince George's County Council Chairman Parris N. Glendening has been cited by the county's ethics board for allegedly violating county laws when he mailed out more than 500 letters to his constituents two months ago asking them to vote against a controversial initiative on the November ballot.

According to the three-member ethics board, Glendening, one of 11 Democrats on the County Council, violated the law when he sent out about 2,500 letters to county voters urging them to vote against ballot question K, a proposal to reduce the council's size to nine members and force all of them to run from districts. Glendening and most of the county's Democratic establishment opposed the initiative, which nonetheless was overwhelmingly approved by the voters on Nov. 4.

The Rev. John Warren, chairman of the ethics board, said yesterday the board felt that county law relating to mailings allows an individual council member or the county executive to use county stationery and postage to send out only 500 pieces of mail on an issue, unless the individual is the first to mail letters on a given subject. The first person to send letters to constituents amount of county stationery and postage, Warren said.

Because Glendening was not the first to send letters on the Question K issue, he was entitled to use county stationery and postage for only 500 letters. According to Glendening's staff, the chairman sent out about 1,500 letters and well reimburse the county treasury for the cost of reproducing and mailing the letters as the ethics board requested.

Glendening said yesterday in a letter to Warren that the board's ruling was "confusing and inconsistent" and that he "simply cannot understand how the board arrive at its findings." He said in the letter his decision to reimburse the county for the mailings does not in any way indicate that he agrees with the ethics board contention that he violated county law.