Nitric Oxide Plant Explosion Investigation - Chemical Accident Reconstruction

Process Hazard Analysis

Nitric Oxide Plant Explosion

Naturally occurring, stable, isotopes of nitrogen and oxygen, such as N-15 and O-18, have considerable value in scientific research and the diagnosis of diseases. These naturally occurring isotopes are harvested by the cryogenic distillation of liquid NO. Typically, the cryogenic distillation columns are 300-feet in length and buried underground, as illustrated in the adjacent figure. In liquid form, nitric oxide (NO) is an unpredictable, highly shock-sensitive, explosive. It is comparable to nitroglycerin.

As often happens, industrial plants are built in rural areas, but for obvious reasons, not too far from major centers of population. As the nearby city grows, residential homes are built closer and closer to the industrial plants. This was the history of a cryogenic distillation plant and when one of the plant's NO distillation columns detonated (see arrow in photo below), more than 2000 residents had to be evacuated. In addition to being explosive, NO gas forms toxic NOx gases when exposed to the atmosphere.

The detonation also caused physical damage to the nearby homes and the homeowners filed a class action lawsuit against the plant.

Chemaxx was asked to investigate the underlying causes for the explosion. A major focus of the investigation was the plant's Process Hazard Analysis (PHA), which is an OSHA and EPA requirement. Dr. Fox is a Certified PHA Team Leader.

The investigation was one that required excruciating detail, even going back to before the first distillation column was built or operated. For example, the original site building and zoning permits were examined. There were at least six distillation columns at the plant site. There had also been earlier, less catastrophic, incidents of detonation that were key factors in the investigation.

The precipitating event for the catastrophic detonation was a leak of NO into the vacuum jacket surrounding the cryogenic distillation column.

Dr. Fox was deposed twice in this case. Portions of the case settled prior to trial and other portions are still ongoing. This was a high-profile explosion that received attention from the U.S. Chemical Safety and Hazard Investigation Board.

Dr. Fox has his Ph.D. in Physical Chemistry and in addition to being a Certified OSHA PHA Team Leader he is a Certified Fire and Explosion Investigator. His specialty is Chemical Accident Reconstruction and he often investigates unique, complex, industrial chemical accidents, fires and explosions.

Dr. Fox is a fire expert, explosion expert and chemical expert with extensive experience in OSHA, EPA, and DOT chemical regulations and chemical safety.