Both HazID and HazOP are risk analysis tools used on the workplace. HazOP, which stands for hazard and operability study, is used to identify abnormalities in the working environment and pinpoint the root causes of the abnormalities. It deals with comprehensive and complex workplace operations, which, if malfunctions were to occur, could lead to significant injury or loss of life.
HazID stands for hazard identification. It is more of a general risk analysis tool designed to alert management to threats and hazards as early in the process as possible. The classification made is done on the basis of probability and consequences. A HazID study provides a qualitative analysis of a worksite in order to determine its worker safety risk level.