Order, Supreme Court, New York County (Leland DeGrasse, J.), entered May 9, 1991, which denied petitioner’s CPLR article 78 application seeking to annul respondent New York City Employees’ Retirement System’s (NYCERS) determination that petitioner was not eligible for a retirement pension, and which dismissed the proceeding, unanimously affirmed, without costs.
Petitioner argues that NYCERS should be estopped from asserting that the membership began in June 1987 because she had relied, to her detriment, on her apparent membership in the retirement system. This reliance was based on the FICA deductions from her paychecks. However, it should have been clear to petitioner from the employee’s guide to NYCERS regulations that the choice to join the system and thereby have FICA deducted was for her to make. (Under NYCERS rules, social security coverage is only available to employees who elect to join the retirement system.) Moreover, after rejoining the system, petitioner purchased service credit for the dates July 1, 1984 to June 25, 1987, thereby establishing that she knew that she was not a member during those years. Respondents were not responsible for any misunderstanding on petitioner’s part with respect to the status of her eligibility for a pension because "those who deal with the government are expected to know the law” (Matter of New York State Med. Transporters Assn. v Perales, 77 NY2d 126, 131). Concur —Sullivan, J. P., Rosenberger, Aseh, Kassal and Rubin, JJ.