The question of whether to grant an application for leave to serve a late notice of claim is left to the sound discretion of the *493court (Matter of Jenkins v New York City Hous. Auth., 181 AD2d 506). Here, that discretion was not improvidently exercised, where petitioner’s excuse for filing the notice of claim six and a half months after the accident, that he did not ascertain the severity of his injury until three months after his accident, is reasonable (Swensen v City of New York, 126 AD2d 499, 501, lv denied 70 NY2d 602). Similarly, the underlying facts of the claim become known to respondent shortly after the expiration of the 90-day statutory time period and, even if the condition which petitioner alleges caused the accident — the lack of handrails on a staircase — has changed, it is likely that respondent made the change and/or kept a record of it. We have considered respondent’s other claims and find them to be without merit. Concur — Murphy, P. J., Rubin, Ross and Tom, JJ.