Define a Major Accident Hazard (MAH) in process safety.

• A. A MAH is a hazard with the potential to cause only minor injuries.
• B. A MAH is a hazard with the potential to cause multiple fatalities, serious injuries, or extensive property or environmental damage from releases, fires, or explosions.
• C. A MAH is a hazard that can be mitigated by PPE alone.
• D. A MAH is a hazard that relates only to environmental damage.

Answer: (B)

Major Accident Hazard means a hazard that could lead to major consequences for people, property, or the environment if something goes wrong with hazardous substances—typically involving releases, fires, or explosions that could cause multiple fatalities, serious injuries, or extensive damage. The focus is on the scale of potential impact, not how likely it is to happen, so MAHs drive rigorous design, safeguards, emergency planning, and regulatory consideration.

For example, a large toxic gas release that could infect a surrounding population, a major flammable vapor release that could ignite and cause a widespread fire or explosion, or a substantial release causing long-lasting environmental contamination—all would be MAHs because of the potential for widespread harm and disruption.

The other descriptions don’t fit MAHs because they either imply only minor harm, rely on protective measures like PPE alone, or limit the concern to environmental damage without addressing possible harm to people or property.