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Safety

Process Safety Since Bhopal

Much has changed, much has stayed the same, and accident investigators worry about future

by JEFF JOHNSON, C&EN WASHINGTON
January 24, 2005 | A version of this story appeared in Volume 83, Issue 4

HARD LESSONS
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Credit: PHOTO BY JEAN-FRANÇOIS TREMBLAY
Bhopal led to a drive for chemical industry process safety that may be fading with time.
Credit: PHOTO BY JEAN-FRANÇOIS TREMBLAY
Bhopal led to a drive for chemical industry process safety that may be fading with time.

Is it safer to work at or live near a chemical plant today than it was 20 years ago, before Bhopal? Maybe.

"I can't say such an accident won't happen in the U.S., but it would be hard to occur," says Dorothy Kellogg, a top American Chemistry Council (ACC) official who manages the chemical industry trade association's plant security and operations activities. She points to improved process safety management and fail-safe systems, better process controls, and automatic shut-off devices, plus better trained and equipped emergency responders.

"And then there is nothing like Bhopal here where people were living cheek by jowl up against the plant's fence line. In the U.S., residents are protected by living in better homes, and they are better trained. They know when to evacuate, when to shelter in place. All these things make it very difficult to have a Bhopal in the U.S."

There is sharp disagreement, however, on nearly all of these points from other plant safety experts, especially those who investigate accidents. They warn that the U.S. has avoided a large accident mostly through luck or chance. Some also worry that the odds of another Bhopal are likely to increase as more and bigger chemical plants are built in developing countries. To stave off another Bhopal, they urge a mix of tougher safety regulations and enforcement, safer manufacturing processes, and a new generation of safety-conscious engineers.

No one denies that since Bhopal there have been improvements in process safety and emergency response. Within months of the disaster, chemical companies and trade associations put together new process safety programs and began a much-heightened focus on safety.

Within years after Bhopal, U.S. laws and regulations were written, calling for new requirements for companies to self-report plant emissions, quantities of chemicals stored on-site, and accident and other data under so-called community right-to-know provisions. The laws gave the Environmental Protection Agency and the Occupational Safety & Health Administration (OSHA) new powers to encourage chemical plant safety.

These laws and regulations also held provisions intended to aid firefighters, police, and other emergency responders so they would be better prepared to know and address what they would face inside a plant should an accident occur.

And Bhopal gave new impetus to a concept called "inherently safer design," in which chemical plants are designed in a manner to reduce risk through use of fundamentally safer systems in the manufacturing process. For instance, lethal, reactive intermediary chemicals, like methyl isocyanate (MIC) or phosgene, are often made and used continuously within the manufacturing process, thereby eliminating large on-site storage, the situation which led to the deaths in Bhopal.

Kellogg
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Credit: ACC PHOTO
Credit: ACC PHOTO

BUT STILL, industrial chemical accidents continue, workers and residents wind up in hospitals or morgues, and communities are evacuated.

"It is eerie how many investigations we do where we find the same conditions that led to the accident at Bhopal," says Carolyn W. Merritt, chairman of the Chemical Safety & Hazard Investigation Board.

Merritt
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Credit: PHOTO BY JEFF JOHNSON
Credit: PHOTO BY JEFF JOHNSON

The board investigates the root cause of U.S. chemical accidents, and its history is directly tied to Bhopal. It was created through provisions of the 1990 Clean Air Act Amendments by members of Congress who didn't want to see a Bhopal happen in the U.S. However, seven years passed before Congress and two U.S. presidents chose to fund the board, and nearly a decade slipped by until its full complement of five commissioners was appointed.

The delay demonstrates a difficulty that sometimes blocks an aggressive accident prevention program. Though no one wants an accident to occur, no one wants to be held responsible for the one that happens. Sometimes, accident ignorance is bliss.

Still, the board has investigated 33 chemical accidents and provided an essential, independent view of U.S. chemical manufacturing and use.

Merritt, a former chemical industry process supervisor, safety manager, and corporate vice president with 30 years' experience, says the U.S. has dodged a chemical tragedy mostly through "luck and good fortune."

"I don't want to give the impression that in the last 20 years nothing good has happened," Merritt continues. "There are companies that are leading the charge with chemical safety, process safety, and integrated chemical management programs, but we still find the same situations that occurred at Bhopal."

Gupta
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Credit: PHOTO BY JEAN-FRANÇOIS TREMBLAY
Credit: PHOTO BY JEAN-FRANÇOIS TREMBLAY

At Bhopal, some 25–40 tons of MIC was released into the atmosphere following a runaway reaction caused by the introduction of around 2,000 lb of water to an MIC storage tank. The water set off an exothermic reaction, and temperature and pressure rose, overcoming relief valves, as well as a refrigeration system, air scrubbers, and flare stack, which were intended to limit the release but were not in working order.

The facility had been downsized and slated for closure, and management was inexperienced and lacked basic knowledge of MIC's reactive hazards, according to several accounts. As the release occurred, there was almost no community notification system despite a shantytown abutting the plant's fence line.

"We see the same things today," Merritt continues. She rolls out several examples, such as DPC Enterprises' accident in Festus, Mo., in August 2002. There, a transfer hose leaked from a chlorine rail tank car at the plant, a system of safety valves failed to work, and emergency personnel were confused and unprepared. They took three hours to find and put on protective equipment needed to enter the site and manually shut off the chlorine leak.

Hendershot
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Credit: PHOTO BY JEFF JOHNSON
Credit: PHOTO BY JEFF JOHNSON

Meanwhile, 24 tons of chlorine was released. Merritt says the only things that saved people living in a 100-unit mobile home park a few yards from the plant's fence line were weather and the time of day.

"There was no breeze to move the heavy chlorine, which settled on the plant's grounds, and it was early in the morning when most people living nearby were gone," Merritt says.

She describes another chemical accident where a policeman heroically ran house to house following an explosion at MFG Chemical Inc. in Dalton, Ga., retching and vomiting as he wrongly told residents to flee their homes to avoid a toxic cloud of allyl alcohol vapor from the plant; an accident at a First Chemical Corp. plant in Pascagoula, Miss., in which inexperienced managers were unaware that a chemical reaction had gone out of control until a 145-foot distillation tower exploded, blasting tons of debris into the air and barely missing nearby toxic chemical storage tanks; and a sign-manufacturing facility that caught fire in downtown Manhattan after workers poured a highly reactive mix of waste chemicals together.

The New York City sign maker, Kaltech Industries, had not been inspected by OSHA in a decade, Merritt notes.

"Most large companies do what they are supposed to do," she says. "They follow the law and even take voluntary steps beyond what's required. But you've got a segment of the population that is doing little or nothing.

"There are a lot of businesses that have not seen an OSHA inspector in a long time. Companies are just like anybody else. If you have a speed limit but police are never there, you are not going to go 25 miles per hour."

She stresses that these accidents are not "engineering mysteries." The hazards are well known, as are the measures to prevent or control them. She argues that many companies put more resources into accountants than safety engineers.

"We've seen companies where the whole business blows up, and they lose everything," she says. It all could have been avoided by hiring an $80,000-a-year safety engineer, she says. Most of these are small companies, Merritt says, but not all. There are accidents at big companies and ACC member companies.

Through its investigations, the board has quantified the obvious--many accidents are caused by uncontrolled reactions. A board survey found 167 reactive chemical accidents that led to 108 deaths over 20 years. In 2003, the board urged OSHA to more closely regulate reactive chemicals and to begin gathering data specifically on reactive chemical accidents. OSHA refused and, a year ago, chose to create a voluntary "reactive alliance" with ACC and other trade associations, as well as EPA and several safety organizations, such as the Center for Chemical Process Safety. The goal is to reach out to chemical makers and users with training and information to lower the risk of reactive accidents.

Kellogg and others in industry believe this is the best path. She adds that ACC's Responsible Care management system is beginning to require third-party auditing of member companies' safety and other management systems. ACC has also begun providing a tabulation of company-specific accident and other data on its website, but details are not provided (C&EN, June 7, 2004, page 24).

ACC member companies, which are the world's largest chemical makers, she says, have a safety record two times better than nonmember companies and more than four times better than all U.S. manufacturers.

Merritt applauds the alliance but still wants OSHA regulations to include reactive chemicals that are not currently regulated. She also wants more aggressive enforcement, especially for small chemical companies and ACC's downstream customers.

EFFECTIVE OVERSIGHT is the "Achilles' heel of the chemical industry," says former safety board member Gerald V. Poje, who retired from the board last year. Poje blames Bhopal on the "tragedy of ineffective process safety management and independent oversight."

Poje notes that both EPA and OSHA have oversight responsibilities, but he argues that "the board has laid out an extraordinarily damaged safety net that exists around reactive chemicals."

Responsible Care, he says, will not make up the difference. ACC's audits have to be real and the results--both good and bad--made public, he says. "Companies have to have someone coming into these plants frequently, with a skeptical eye, testing if the safety systems are actually working."

Poje says accidents are not just problems for small companies or for U.S. companies. He points to an ammonium nitrate explosion that killed 31 people and injured 2,442 in Toulouse, France, in 2001. The company, then called Atofina, is an ACC member and one of the world's largest chemical makers.

The explosive nature of ammonium nitrate is well understood, and it has been responsible for nearly a century's worth of huge, deadly disasters, he notes.

"What happened at Toulouse speaks to the need for a renewed sense of vigilance," Poje adds.

Poor process safety management is Bhopal's message to Trevor Kletz. The stored quantities of MIC, an intermediate used to make pesticides, were unnecessary. "If MIC had been used as it was made, the worst possible leak would have been a few kilograms," he says.

Kletz is the father of inherently safer design. He writes and teaches part time now, after working as a chemical engineer for 38 years with Imperial Chemical Industries.

Inherently safer design is a safety hierarchy to guide an examination of chemical manufacturing processes. At the top is removing the hazard altogether, next comes passive process controls, then more active controls, and last is having complex operating procedures--when all else fails (C&EN, Feb. 3, 2003, page 23).

WITHIN A YEAR after Bhopal, Kletz says, companies around the world were boasting that they had reduced or eliminated stockpiles of hazardous intermediaries. Today, he says, hazardous intermediates are rarely stocked and the normal practice is to make them as you use them. The wider message, however, to apply inherently safer designs throughout the manufacturing process has not gone over as well, Kletz fears.

Safety engineers know the concept, but top management does not. To work, it must be applied from the beginning of planning a process change or new construction. Instead, safety engineers are brought in at the end and wind up adding safety devices to control rather than to eliminate the hazard, which is "good but trivial," Kletz says.

"The tendency is to use the existing designs on new plant construction," he says, because regulators accept those designs more easily, they are quicker and simpler, and everyone knows they work.

This is true, he says, in both developed countries and in the developing world, which is now experiencing a chemical plant construction boom.

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J. P. Gupta, a chemical engineering professor at Indian Institute of Technology, agrees that adoption of inherently safer designs has been slow. But he adds that Bhopal led to process safety changes that saved thousands of lives. He notes, however, that applying inherently safer designs in the developing world will be difficult. "Companies don't like new approaches. There is a race to be second. Let someone else try it first."

But new plant construction in Asia and the developing world may be importing risk from developed nations, warns David W. Edwards, an industry consultant and fellow in the department of chemical engineering at Loughborough University, in England. He sees companies scaling up traditional designs and missing an opportunity to use inherently safer processes where they might be of great value.

"Traditional designs may be fine," he says, "when the plants are all shiny and new and staffed by expatriates and making money and everything in the garden is rosy. But what will happen a few years down the road when maybe the plants have been sold off to a new buyer and are not making any money, and the people who run them aren't so well trained or aware of hazards, and staff has been cut? Remember, that is what happened at Bhopal."

Rohm and Haas was one of the companies that learned from Bhopal, says Dennis C. Hendershot, senior technical fellow with the company. Right after Bhopal, his company sent out inspection "SWAT" teams to every plant. The effort grew into an ongoing, site-driven accident prevention program, he says.

The company considers inherently safer designs wherever possible, both in the U.S. and in its plants around the world, he says, adding that he believes many large companies are doing the same. But almost no data exist on safety processes used in new construction, and most engineers worry that demands for quick construction and good profits will trump long planning timelines and financial investments needed to build safer plants in poorer parts of the world.

To encourage safer designs, Kletz and Hendershot want chemical engineering schools to require courses in process safety. Educators estimate that only a handful of U.S. schools currently require process safety courses.

Many graduating chemical engineers don't have a good foundation in reactive chemistry hazards, Hendershot says. "They get trained when they come to work at a Rohm and Haas or a Dow, but not so with smaller companies."

The need for educational changes is also stressed by Ronald J. Willey, Northeastern University chemical engineering professor. But Willey warns that chemical engineering professors need more industrial experience. "We tend to hire teachers who are international academic experts in very narrow areas of chemical engineering, such as molecular engineering, nanotechnologies, and so on. But chemical engineers deal in barrels and tons. There is a disconnect in understanding the importance of process safety in the classroom."

Most students today are unaware of Bhopal, Kletz says, and he worries that its lessons are fading. Studying failures, he adds, is the best teaching device, much better than successes.

"There is an old saying that success makes us clever, but problems make us wise."

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