Claimant's decedent worked as an assistant supervisor at a housing project under the jurisdiction of the City of New York Housing Authority when, in November of 1974, he became ill at work and was taken by ambulance to the hospital. He died there several days later of a massive cerebral hemorrhage. The board found that decedent's death was causally related to his work activities and thus compensable under the Workers' Compensation Law. The board further excused the failure to comply with the 30-day notice requirement of section 18 of the Workers' Compensation Law on the finding that the employer had knowledge of the accident. The board's decision must be affirmed. The testimony of a co-worker concerning decedent's activities at the time he became ill, coupled with the medical opinion of decedent's doctor who testified that such physical activity was the cause of the cerebral hemorrhage from which decedent died, constitute substantial evidence to support the finding of a compensable accident. Further, the board properly found that the employer had knowledge of the accident through the personal knowledge of decedent's immediate supervisor who summoned the ambulance which carried decedent to the hospital. Decision affirmed, with costs to the Workers' Compensation Board. Mahoney, P.J., Sweeney, Kane, Casey and Mikoll, JJ., concur.