Chemical Process Safety at a Crossroads
Merritt, Carolyn W., Environmental Health Perspectives
December 2004 will mark the 20th anniversary of the worst industrial accident in history, the chemical plant disaster in Bhopal, India, that killed thousands of people and injured tens of thousands more. Along with other safety professionals from around the world, I will be traveling to India this fall to reflect on what has changed and what we still must do to better protect the lives of workers and the public from chemical accidents.
Chi ([chi]), the 22nd letter of the Greek alphabet, is an ancient symbol of a crossroads. At its center, the intersection point, or chiasm, marks a single event that separates past from future. Bhopal is a chiasm, an event that forever changed the path of the chemical industry and that continues to be felt around the world.
Thousands of Bhopal victims suffered permanent, disabling injuries, which they must live with every day. The tragedy has also changed public attitudes toward the chemical industry in lasting ways. The U.S. Congress passed the Emergency Planning and Community Right-to-Know Act (1986), followed by the Clean Air Act Amendments (1990). These laws have established a federal role in overseeing how companies manage the safety of chemical processes on a daily basis.
As directed by Congress, the U.S. Occupational Safety and Health Administration (OSHA 1992) and the U.S. Environmental Protection Agency (U.S. EPA 1996) issued regulations requiring companies to analyze the hazards of their processes, preserve safety during process changes, perform preventative maintenance, train workers and contractors, investigate safety incidents, and plan for emergencies. The rules do not require specific safety equipment or define an acceptable level of risk to workers or the public, but they do require companies to establish broad safety management systems before processing various hazardous chemicals. As radical as the rules were in some ways, in one important respect they were decidedly conventional: to be covered under the standards, a facility needs to use at least a threshold quantity of one of approximately 100 enumerated chemical substances or classes. Thus most chemical processes today are not covered under the safety rules.
Beyond mandating new regulations, the Clean Air Act Amendments (1990) authorized creation of a new independent federal agency, the U.S. Chemical Safety and Hazard Investigation Board (CSB), which investigates the root causes of serious chemical accidents that harm workers or the public. Governed by a board of five safety experts appointed by the president and confirmed by the Senate, the CSB has the authority to recommend needed safety improvements to the U.S. EPA, OSHA, industry, and other organizations, based on its investigations of accidents and hazards. Although the CSB was not funded until 1997, it is currently a fully operational body that investigates up to a dozen major chemical accidents each year and reports its findings to the public and Congress.
One ongoing purpose of the CSB is to evaluate just how effective OSHA and U.S. EPA process safety regulations are. Virtually since the CSB opened its doors, members began to realize that these rules had potentially serious gaps. The rules address hazards of individual chemicals, such as flammability, toxicity, and instability, but not the hazards of chemical reactions. Controlled chemical reactions are essential to manufacturing, but uncontrolled reactions have led to numerous accidents. For example, a chemical reaction can "run away" if excess heat is generated and not removed quickly enough. Uncontrolled reactions can generate gases that cause explosions or toxic releases. Other serious accidents are caused by inadvertent mixing of incompatible substances.
About one-third of the major accidents the CSB has investigated since 1998 are these "reactive" accidents--where a sudden, uncontrolled chemical reaction causes deaths, injuries, or serious damage. The following are among the more notorious examples:
* On 8 April 1998, an explosion and fire occurred during the production of a dye at a chemical plant in Paterson, New Jersey (CSB 2000). …