Order unanimously modified, on the law, and as modified, affirmed, without costs, in accordance with the following memorandum: Special Term erred in denying claimants' motion pursuant to General Municipal Law § 50-e (5) for leave to serve a late notice of claim. At the time of the accident the defendant's chief operator of the sewage treatment plant was present on the site and directed traffic so that the injured claimant could be taken to the hospital. This afforded defendant actual knowledge of the essential facts constituting the claim (see, e.g., Mestel v. Board of Educ., 90 A.D.2d 809; Matter of Ziecker v. Town of Orchard Park, 70 A.D.2d 422, affd 51 N.Y.2d 957). As defendant had actual knowledge of the claim and has not suffered substantial prejudice by the delay, claimants' motion to serve a late notice of claim is granted (see, Matter of Beary v. City of Rye, 44 N.Y.2d 398, 412-413).