—In a proceeding pursuant to CPLR article 75 to set aside an arbitration award dated December 16, 1998, reinstating Donald Holtum to his position as Lead Technical Assistant at Westchester Community College, the Civil Service Employees Association, Inc., Local 860, Westchester County Unit, and Donald Holtum appeal from an order and judgment (one paper) of the Supreme Court, Westchester County (Donovan, J.), entered August 18, 1999, which granted the petition, denied their cross motion to confirm the award, and vacated the award.
Ordered that the order and judgment is affirmed, with costs.
The arbitrator’s interpretation of the parties’ collective bargaining agreement is unsupported by the plain language of that agreement, and the award was properly set aside as irrational (see, Matter of Board of Elections v O’Rourke, 210 AD2d 402; County of Chautauqua v Chautauqua County Employees’ Unit 6300, 181 AD2d 1052, 1053; see also, Matter of County of Nassau [Nassau Community Coll.] v New York State Pub. Empl. Relations Bd., 76 NY2d 579; Cook, MLA’s Line by Line, at 112-113 [Houghton Mifflin Co. 1985]). O’Brien, J. P., Sullivan, Goldstein and H. Miller, JJ., concur.