On August 01, 2019, about 1615 Pacific daylight time, a Cessna P210, N234SB, was substantially damaged when it was involved in an accident at Gnoss Field Airport, Novato, California. The private pilot and one passenger were not injured. The airplane was operated under the provisions of 14 Code of Federal Regulations Part 91 as a business flight. The pilot reported that, after making a normal approach, he configured the airplane to land on runway 13. As the airplane passed over the runway designation markings (numbers), the nose felt as though it was being forced down and impacted the runway surface. The airplane bounced and subsequently touched down again, resulting in the nose gear collapsing. The propeller contacted the runway and the airplane veered off the asphalt, coming to rest in the grass median. The pilot thought that the nose gear collapsed a result of a failure of the lower trunnion failing, which was the subject of Cessna Service Bulletin SEB94-19, issued in July 1994. The bulletin states that the lower trunnion failures occur forward of the side brace as a result of cracks caused by improper ground handling procedures. The bulletin advised inspection of the nose landing gear lower trunnion for cracks until trunnions could be replaced with a new strengthened lower trunnion. It could not be ascertained if the airplane was maintained in compliance with service bulletin, nor is it mandatory for the owner to have complied. The accident trunnion did not have signatures consistent with a failure occurring in the area of concern. The Federal Aviation Administration-certified airframe and powerplant mechanic that performed a postaccident examination of the nose gear stated that the fork had fractured and was bent aft. He said the appearance of the retraction cylinder was consistent with it impacting while in compression; the links were intact. He thought all the signatures were consistent with the nose strut failing as a result of a heavy aft force that would occur with an extreme nose-low impact or encounter with an obstacle.