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Deconstructing Inherently Safer Technology

Proponents say requiring IST would prevent deadly refinery, chemical plant accidents; industry says it’s already in use and working

by Glenn Hess , Jeff Johnson
March 10, 2014 | A version of this story appeared in Volume 92, Issue 10

The aftermath of a fertilizer plant explosion in West, Texas, early on April 18, 2013.
An explosion at the West Fertilizer depot near Waco, Texas, on April 18, 2013, prompted the establishment of a federal task force to find ways to improve chemical facility safety and added to the calls for an IST mandate.

In the early hours of April 2, 2010, a deadly fire and explosion ripped through the Tesoro refinery in Anacortes, Wash., which is 70 miles north of Seattle. Seven workers died when a pipe ruptured during routine maintenance of a naphtha hydrotreater unit, according to Tesoro and the Chemical Safety & Hazard Investigation Board (CSB).

Beyond the ruptured pipe, the facility suffered from hazardous working conditions and “a deficient safety culture,” according to CSB’s recent report on the accident.

This accident is just one in a series of fatal industrial accidents that have rekindled a long-running, hard-fought debate over whether federal and state governments should require facilities that process or store hazardous chemicals to take steps to make their operations inherently safer. In the Tesoro accident, such action could have prevented the workers’ deaths, CSB and others argue.

Inherently safer systems and technologies are analytical tools that chemical engineers can use to compare options within a given manufacturing process. The goal is to encourage substitution for or minimization of hazardous chemicals as well as simplification of complex industrial processes that use hazardous chemicals.

Some chemical engineers call the inherently safer technology (IST) analysis plain common sense. Because of its inherent nature, they see no need for regulations that mandate its use.

Environmental groups, labor unions, and some other chemical engineers, in contrast, feel mandated IST is necessary to ensure industry safety.

“What we have now is risk management; what we need is risk prevention,” says Rick Hind, legislative director of the environmental group Greenpeace. “Risk management accepts the risk and simply cleans up the mess afterward. This isn’t acceptable and shouldn’t be acceptable to people who lost family members or their homes” in the recent accidents.

Green groups and other activists are urging that IST assessments be required in a report under development by a key federal task force.

The health and safety regulations enforced by the Occupational Safety & Health Administration (OSHA) and state regulators do not currently require an IST assessment. The interagency task force was appointed by President Barack Obama last August and is exploring ways to make chemical facilities safer and more secure. Led by the Environmental Protection Agency, OSHA, and the Department of Homeland Security (DHS), the working group has until May 1 to deliver its recommendations.

The push for an IST mandate is also being led by CSB, which is concerned about a rash of refinery accidents. Over the past few months, the board has included IST recommendations in its investigatory reports of explosions and fires at a Chevron facility in Richmond, Calif., which sent 15,000 residents to area hospitals, and at the Tesoro refinery. CSB has also documented significant safety problems throughout the petrochemical industry, including 125 significant accidents in 2012. The board notes that six of its current backlog of 13 investigations are of deadly refinery accidents.

Then a few weeks ago, a panel created by California Gov. Edmund G. (Jerry) Brown Jr. (D) after the Chevron accident weighed in, recommending that state enforcement agencies consider requiring IST analyses in regulatory decisions.


But the debate over IST has been going on for more than a decade. The concept was developed and promoted by Trevor Kletz, who died last year. For 38 years, Kletz was a chemical engineer with Imperial Chemical Industries in the U.K., and in retirement he was a professor and adviser to several universities and safety institutions.

Kletz developed and described an IST hierarchy of actions: Minimize use of hazardous chemicals, substitute or replace hazardous chemicals with safer ones, moderate or shift to less hazardous chemicals or processes at lower temperatures and pressures, and simplify processes and design plants to eliminate unnecessary complexity.

“The very best way to prevent an explosion is to simply replace the material that explodes with one that does not, or at least keep the stock down so low that it hardly matters if it all leaks out,” he told C&EN in 2003. More elaborate safety controls on a hazardous operation are the opposite of IST, Kletz explained; eliminating the hazard is the goal.

As in the past, today’s emphasis on safety springs from deadly industrial chemical accidents, which have occurred over the past half-dozen years.


Supporters and detractors of mandating inherently safer technology make their arguments.

Requiring facilities to use safer chemicals and processes "when they're available, effective and affordable is common sense. Many companies have acted responsibly, but far too many others have not."

—Christine Todd Whitman, former EPA administrator

"What we have now is risk management; what we need is risk prevention. Risk management accepts the risk and simply cleans up the mess afterward."

—Rick Hind, legislative director of Greenpeace

Requiring chemical storage facilities to reduce inventories of certain products "would prevent some companies from effectively meeting their customers' needs."

—Jennifer Gibson, vice president of regulatory affairs at the National Association of Chemical Distributors

"Inherent safety is a superficially simple but truthfully very complex concept, and one that is inherently unsuited to regulation."

—William E. Allmond IV, vice president of government and public relations, Society of Chemical Manufacturers & Affiliates

There are numerous existing federal regulatory programs that "already require companies to take a hard look at their operations and do what it takes to make them safe and secure."

—Peter Lodal, technical fellow at Eastman Chemical

The Obama task force review, in fact, was largely prompted by the massive April 2013 ammonium nitrate explosion at a West, Texas, fertilizer distributor. The accident claimed 15 lives, including a dozen firefighters.

Adding weight to the task force review are two other chemical facility disasters that occurred last June—an explosion at the Williams Olefins plant in Geismar, La., that left two dead and 114 injured and an accident at CF Industries in Donaldsonville, La., that killed one worker and injured seven.

“We have more fertilizer and chemical plants in our petrochemical corridor than anywhere else in the country,” says Juan Parras of the Houston-based Texas Environmental Justice Advocacy Services. “I hope that President Obama comes up with a real policy that protects our community from the dangers of these chemicals.”

In interviews, CSB officials say two other accidents have also driven concerns and caused the push for IST. One is the 2005 BP Texas City, Texas, refinery tragedy that killed 15 workers and injured 180 others. The board’s investigation and report led to a short-lived OSHA program to emphasize refinery safety.

Another is a 2008 explosion at the Bayer CropScience pesticide plant near Charleston, W.Va. The accident killed two workers and sent debris flying that nearly hit a storage tank holding 13,000 lb of methyl isocyanate (MIC), a highly toxic intermediate that caused thousands of deaths in 1984 when it leaked from a chemical plant in Bhopal, India. The Bayer accident led CSB to recommend an IST-driven phaseout of MIC at the plant. Congress also provided $600,000 for a review by the National Academy of Sciences on the applications of IST at the plant. Eventually Bayer ended MIC use and NAS finished its report, but accidents kept occurring.

“The U.S. is facing an industrial chemical safety crisis,” wrote CSB head Rafael Moure-Eraso, in a recent New York Times editorial in which he stated his case for IST. “Sifting through chemical-plant rubble from catastrophic accidents year after year, our board has long called on regulators to require—and for industry to adopt—what is known as inherently safer technology.”

Moure-Eraso called for regulations in his editorial. “We can’t wait for corporations to volunteer,” he said, “because the accidents continue.”

Despite these new bursts of IST advocacy, industry officials remain steadfast in their opposition to mandatory consideration or implementation of IST. Within days of Moure-Eraso’s editorial, three industry trade associations—the American Chemistry Council (ACC), the Society of Chemical Manufacturers & Affiliates (SOCMA), and the American Fuel & Petrochemical Manufacturers—shot back on the newspaper’s pages in letters to the editor.

IST is “an engineering philosophy, not a technique,” they wrote, adding that the U.S. “has some of the most stringent regulations in the world.” They stated that the refining and chemical industries are among the nation’s “safest manufacturing industries.”

Instead of new regulations, they urged that regulators focus on improving existing enforcement and compliance so all facility operators “understand and live up to their obligations.”

Industry officials stress that they oppose reliance on any single risk reduction tool, particularly IST. They argue that a federal or state mandate for safer approaches, such as switching to less toxic chemicals, could force elimination of some hazardous yet essential intermediary or final chemical products.

Reducing chemical storage inventories of some products “would prevent some companies from effectively meeting their customers’ needs,” adds Jennifer Gibson, vice president of regulatory affairs at the National Association of Chemical Distributors, a trade association.

In addition, if facilities are required to reduce the amount of materials they have on-site, Gibson observes, the result would be increased transportation of the materials, shifting risk to different points along the supply chain and increasing the likelihood of loading, unloading, or in-transit incidents.

“Inherent safety is a superficially simple but truthfully very complex concept, and one that is inherently unsuited to regulation,” adds William E. Allmond IV, SOCMA’s vice president of government and public relations. Judgments about process safety are complex, he says, and should be made by facility operators, not by “busy government officials sitting miles away reviewing documents.”


One Man, One Goal: Safer Chemical Plants

Trevor Kletz, the developer of inherently safer technology (IST), was drawn into the safety field by a chemical plant accident. He’s not alone in that. For Kletz, a chemical engineer with industry and academic experience who died last year, that accident was the 1974 plant explosion in Flixborough, England, in which 28 workers died and plant fires burned for more than a week. The facility made an intermediate for the production of nylon and used cyclohexane, which ignited. The accident occurred on a weekend, but if the plant had exploded during the workweek hundreds more would have died.

“Why such a big explosion?” Kletz asked, as he explored the manufacturing process. He discovered that of the cyclohexane used in each cycle through the manufacturing system, only 6% was converted to product. Consequently, the facility’s inventory was far beyond what was needed for production. Kletz calculated that with a more efficient process, the plant could have been one-seventeenth the size and still have made the same amount of product.

“It was appallingly bad engineering,” he told C&EN in 2003. That examination led him to develop IST.

He described a “step change” in chemically related manufacturing that has occurred since the 1960s with bigger plants operating with higher temperatures and pressures. “If you made a mistake and opened a pipe at the wrong time in the past, you might have gotten away with it, but not in the future as the plants got bigger.”

Kletz acknowledged that facility managers and operators are in a bind. Safety certainly matters to them, but they are paid to put product out the door, and as international competition heats up and chemical companies continue to downsize staff, safety concerns always risk being marginalized.

Industries’ traditional solution to increased levels of hazard and increased production, he said, has been more controls. But he came to realize it was time for a whole new approach to controlling hazards—inherently safer designs.

Many people, Allmond says, believe inherent safety can be achieved only by reducing the amount of hazardous chemicals used in manufacturing and processing. But he warns that a simple reduction in the use of some chemicals is often not possible or may result only in the redistribution of risk, without actually reducing it. He also says there is no agreed-upon methodology to measure whether one process is safer than another.

However, a well-developed school of thought in the application of IST has grown over the past 35 years, notes Paul Amyotte, chemical engineering professor at Dalhousie University, in Halifax, Nova Scotia, who was a member of the NAS review committee. He is also president-elect of Engineers Canada, a national professional engineering society.

The full development of IST, he says, “does not mean that inherent safety is a cure for all ills or IST principles can be fully implemented in all scenarios.” IST, instead, rests at the top of a hierarchy of ways to reduce risk at industrial facilities, and its use should be required, he says.

Amyotte and CSB’s Moure-Eraso point out that in both the Chevron and Tesoro accidents if IST principles had been applied, the accidents would have been avoided. Both accidents were caused by cracked and corroded carbon steel piping that should have been replaced years before the accidents occurred. The degradation problems were known to the companies, and an IST analysis would have led to their replacement with stainless steel components.

They want the U.S. to adopt a regulatory system similar to one used by the U.K.’s Health & Safety Executive (HSE), which regulates workplace safety in England.

That program’s goal is to reduce risks to “as low as reasonably practical,” explains Ian Travers, who oversees HSE’s chemical hazard division. To reach this level, an operator must include an IST examination of costs and benefits of low-risk alternatives. New facilities are required to conduct an initial risk review, including IST options, during design. Existing facilities are required to periodically review and revise their operations, showing that they have taken into account new technology or knowledge to reduce hazards and risks; these analyses include cost-effective IST options.

An example of a successful application of the U.K. program, Travers says, is the Buncefield fuel depot fire of 2005, a large explosion and fire at a gasoline storage facility in England that gained notoriety throughout Europe. The HSE investigation led to an IST analysis. This analysis forced the fuel depot to upgrade its overfill protection and install high-integrity tanks and automatic shutdown systems, which are considered safer than manually operated systems. The risk reduction benefit far outweighed the cost of the upgrades, Travers adds.

Still, notes Peter Lodal, technical fellow with Eastman Chemical in Kingsport, Tenn., the U.S. has numerous existing federal regulatory programs that “already require companies to take a hard look at their operations and do what it takes to make them safe and secure.” He cites OSHA’s process safety management (PSM) standard, which seeks to prevent workers from being exposed to hazardous chemicals, and EPA’s Risk Management Plan (RMP) rule, which is designed to prevent accidental releases of harmful substances and to mitigate the severity of releases that do occur.

Explicit mandates for safer alternatives are not needed, adds Lodal, who also chairs ACC’s Process Safety Committee. Operators need to take a holistic approach when addressing risk at their facilities, Lodal continues. “These programs and requirements need to be addressed in concert, so the overall safety and security profile can be maintained at the highest level possible while allowing the facility to function. No one agency has the legal authority or technical capacity to perform this task.”


Reports by CSB acknowledge that chemical plants and refineries are already covered by PSM and RMP standards, particularly large facilities such as the ones where the recent accidents occurred. However, accidents continue. For this reason, CSB recommends that a system be set up in the U.S. akin to the one in place in the U.K.

CSB, along with environmental and labor groups, believes EPA could require IST examinations through the General Duty Clause of the 1990 Clean Air Act. Under the law, companies that produce, process, and store toxic chemicals have a general duty to identify hazards, design and maintain safe facilities, and minimize the consequences of any accidental releases.

That view of the authority vested in the General Duty Clause is shared by former EPA administrator Christine Todd Whitman, who led the agency from 2001 to 2003. She notes that more than 470 chemical facilities in the U.S. each put 100,000 or more people at risk in the event of a poison gas disaster, according to the Congressional Research Service, Congress’s policy research arm.

“People’s lives are at stake. That’s why we need to have action at the federal level,” Whitman says. Requiring facilities to use safer chemicals and processes “when they’re available, effective, and affordable is common sense.”

Since the terrorist attacks on Sept. 11, 2001, she says, hundreds of chemical facilities have modified their manufacturing processes. Clorox Co., for example, has converted all of its U.S. facilities from chlorine to high-strength bleach as a raw material for making its namesake bleach. “Many companies have acted responsibly, but far too many others have not,” Whitman says.

Industry officials argue that current regulatory programs, coupled with the marketplace itself, provide strong incentives for companies to consider and adopt safer alternatives, such as IST.

When asked for examples, they point to the Chemical Facility Anti-Terrorism Standards (CFATS) program, which Congress directed DHS to create after the 9/11 terrorist attacks.

Under CFATS, companies are required to make substantial financial investments to address a range of security concerns, including protecting their facilities against potential attacks and preventing the theft of dangerous chemicals. The chemical industry has spent almost $13 billion on security enhancements over the past decade, according to ACC.

Since CFATS was launched, DHS has screened approximately 46,000 chemical facilities across the country and determined that about 7,000 are “high-risk” targets because of the types and amounts of chemicals stored, used, or produced on-site. But so far, more than 3,000 facilities have voluntarily changed production processes or reduced hazardous chemical inventories below threshold levels, enabling them to exit the program and avoid its costly requirements.

“CFATS is driving facilities to reduce inherent hazards,” says Matthew J. Leary, corporate environment, health, safety, and security manager for Pilot Chemical, in Cincinnati. “And this risk reduction has taken place through a market-based approach.”

Whether market-based, regulatory-driven, or just plain common sense, the shift to IST is slowly happening and is likely to continue. The speed of implementation, however, will continue to collide with safety, money, and process controls.  


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