There is a saying when it comes to workplace issues - "if it isn't in writing, it didn't happen". This very much applies to risk assessments of hazards. It is essential that all details are recorded and documented when it comes to risk assessments. If a hazard was reported, action taken, but not documented, there is every chance that if that hazard re-appears and someone is injured you could be facing a serious court judgement on your failure to act on the hazard.