As an employee, it is the job of your employer to make sure that you are safe on the job. He must tell you about any safety or health issues that could effect you in your line of work. Your boss is also legally obligated to report any accident at work and if you are so entitled, pay you for your time off work because of that accident.
Your employer must report dangerous incidents, accidents that are work related and any diseases must be reported to the Incident Contract Center of the Health and Safety Executive. Your boss is obligated to report any injury that keeps you from working for over three days, a death that occurs and any major injuries like broken ribs, arm or legs. He must also report any incident that was dangerous like a scaffolding that collapsed or if a worker was overcome by gas of some sort.
If you were involved in any of these things, then you would be wise to make sure that it was reported because your employer might not have done it. It is up to your employer to see that you are safe on the job and than any visitors are safe as well.