Unless this action violates the terms of an employment contract or union agreement, you have no claim here. The fact is that in an "at will" work arrangement, an employer can set the conditions of the workplace much as it sees fit (absent some form of legally actionable discrimination). This includes checking on an accident report. If you fail to provide this information, you can be disciplined up to and including termination. In fact, you can be fired for any reason or no reason at all, with or without notice.