Where a liability insurance policy requires notice of an occurrence to the carrier as soon as practicable, such notice must be given within a reasonable period of time ( Great Canal Realty Corp. v Seneca Ins. Co., Inc., 5 NY3d 742). The insured's noncompliance with this requirement constitutes failure of a condition precedent, thus vitiating the contract as a matter of law, even without a showing of prejudice ( Argo Corp. v Greater N.Y. Mut. Ins. Co., 4 NY3d 332, 339).

Plaintiff became aware of the claimant's accident within three days, but did not notify Tower of the possibility of a claim until eight months later. Where a reasonable person could envision liability, that person has a duty to make some inquiry as to potential liability ( White v City of New York, 81 NY2d 955, 958). Although a good faith belief in nonliability may excuse the failure to give timely notice ( see Great Canal Realty Corp., 5 NY3d at 743), there is no indication that plaintiff ever took any action to ascertain the possibility of its liability for the claimant's accident. Had plaintiffs president questioned his employees, some of whom had witnessed the accident, he would have learned that the claimant, after falling in front of the premises, had been taken away in an ambulance. Since he made no investigation at all, there is no basis for a good faith belief in plaintiffs nonliability.