Different health hazards are caused by e.g. accident hazards, chemical and physical hazards, ergonomics flaws and mental load. The latter is closely related with working environment and mental well-being in the work community which is affected by e.g. inappropriate behaviour at work. 

It is important that all the hazards are measured systematically in the same way i.e. commensurably.  Hazard-specific checklists are helpful.   Usually they focus on the hazards that are immediately sensed and detected.

The employee is the best expert of hazards of their own work. At work, many hazards may, however, be left unidentified or they are ignored as an instinctive reaction to make the work smoother. Therefore, in the risk assessment we need industrial safety and occupational health professionals and other experts familiar with the task.