Extremely Hazardous Substances - A Focus on Safer Operations

The Risk Management Program (RMP Rule) regulates accidental chemical releases at U.S. chemical process plants. Its goal is to minimize the likelihood of serious chemical accidents that could impact public health and the environment.

In recent years, the RMP Rule has been well-publicized (Chem. Eng., December 1998, pp. 114–120; and May 1997, pp. 169–176) and has changed the way many CPI facilities are operated. However, one component — the “general duty clause” in Section 112(r)(1) — has not been as widely embraced by CPI firms, yet its impact is every bit as substantive for operators.

The RMP Rule — established by the U.S. Environmental Protection Agency (EPA) under Section 112(r) of the U.S. Clean Air Act (CAA) Amendments of 1990 — applies to any process that contains a listed substance in excess of its specified threshold quantity (TQ). The term “process” is broadly defined to include any use, storage, manufacturing or handling activities that involve TQ or greater volumes of the 77 toxic substances, 63 flammable materials, and certain high explosives listed in CAA Section 112(r) (40CFR Section 68).

Regulated owners and operators were required to submit a detailed risk-management plan to EPA by June 20, 1999. Those processes commissioned after the original submission date must submit risk-management plans before the covered chemical is onsite at quantities above its TQ. Such plans must be updated and resubmitted to EPA within five years of either the initial submission or the most recent revision, whichever is later.

Such plans must be revised within six months of any process change that:

• Requires a substantial or major revision to the process hazard analysis (PHA) or hazard review; or
• Is expected to increase (or decrease) the distance to the toxic endpoint by a factor of two or more

In contrast, the RMP Rule’s general duty clause directs owners and operators of stationary sources¹ to identify and control hazards that may result from the use of any “extremely hazardous substance,” regardless of quantity. Unfortunately, extremely hazardous substances are not defined in the CAA Amendments, and their definition is left somewhat to the discretion of regulators. These substances are neither limited to the list of regulated substances under Section 112(r), nor to the list of extremely hazardous substances provided in EPA’s Emergency Planning and Community Right-to-Know Act (EPCRA; 40CFR Section 355). Additional guidance for identifying extremely hazardous substances is provided in the box (above).

The general duty clause is a performance-based regulation that requires owners and operators of stationary sources to:

• dentify hazards that may result from accidental releases (see the box on p. 110), using appropriate hazard-assessment techniques
• Design and maintain a safe facility by taking steps that are necessary to prevent releases
• Minimize the consequences of accidental releases that do occur

1. A stationary source is defined as any “buildings, structures, equipment, installations or substance-emitting stationary activities that: 1) belong to the same industrial group; 2) are located on one or more contiguous properties; 3) are under the control of the same person (or persons under common control); and 4) may result in an accidental release.”

The Risk Management Program (RMP Rule) regulates accidental chemical releases at U.S. chemical process plants. Its goal is to minimize the likelihood of serious chemical accidents that could impact public health and the environment.

In recent years, the RMP Rule has been well-publicized (Chem. Eng., December 1998, pp. 114–120; and May 1997, pp. 169–176) and has changed the way many CPI facilities are operated. However, one component — the “general duty clause” in Section 112(r)(1) — has not been as widely embraced by CPI firms, yet its impact is every bit as substantive for operators.

The RMP Rule — established by the U.S. Environmental Protection Agency (EPA) under Section 112(r) of the U.S. Clean Air Act (CAA) Amendments of 1990 — applies to any process that contains a listed substance in excess of its specified threshold quantity (TQ). The term “process” is broadly defined to include any use, storage, manufacturing or handling activities that involve TQ or greater volumes of the 77 toxic substances, 63 flammable materials, and certain high explosives listed in CAA Section 112(r) (40CFR Section 68).

Regulated owners and operators were required to submit a detailed risk-management plan to EPA by June 20, 1999. Those...