The report is one of a series of manuals addressing accidental releases of toxic chemicals. Methyl isocyanate (MIC) has an Immediately Dangerous to Life and Health (IDLH) concentration of 20 ppm, making it a substantially acute toxic hazard. Reducing the risk associated with an accidental release of MIC involves identifying some of the potential causes of accidental releases that apply to processes that use MIC. The manual identifies examples of potential causes and measures that may be taken to reduce the accidental release risk. Such measures include recommendations on plant design practices, prevention, protection, and mitigation technologies, and operation and maintenance practices. Conceptual cost estimates of possible prevention, protection, and mitigation measures are provided.