Operators in a powdered metals production facility heard a hissing noise near one of the plant furnaces and determined that it was a gas leak in the trench below the furnaces. The trench carried hydrogen, nitrogen, and cooling water runoff pipes as well as a vent pipe for the furnaces.

Maintenance personnel presumed that the leak was nonflammable nitrogen because there had recently been a nitrogen piping leak elsewhere in the plant. Using the plant's overhead crane, they removed some of the heavy trench covers. They determined that the leak was in an area that the crane could not reach, so they brought in a forklift with a chain to remove the trench covers in that area.

Eyewitnesses stated that as the first trench cover was wrenched from its position by the forklift view more

An explosion occurred in a 90-ton-per-day incinerator at a municipal refuse incineration facility. Three workers were seriously burned by high-temperature gas that spouted from the inspection door, and one of them died 10 days later. The accident happened during inspection and repair of the furnace ash chute damper. The workers injected water to remove some blockage, and the water reacted with incinerated aluminum ash to form hydrogen, which caused the explosion.

Workers noticed that the post-combustion zone was full of ash and the ash pusher was not working properly, so they tried to remove the ash from the inspection door with a shovel. They discovered a solid layer of "clinker", which is formed by solidification of molten material such as aluminum. The explosion view more

A hydrogen explosion and fire occurred in the benzene unit of a styrene plant in a large petrochemical complex. The unit was being restarted following a scheduled maintenance shutdown. The explosion followed the release of about 30 kilograms of 700-psig hydrogen gas from a burst flange into a compressor shed. Two men were killed and two others were injured. If it had not been a holiday, the death toll and injuries would probably have been much worse.

The operators were bringing the plant online and increasing the hydrogen circulation pressure. About 10-15 seconds before the explosion, they heard a pop and then a loud hiss of pressure being released within the compressor shed. Witnesses reported seeing a white flash and then a large fireball. The fires burned out in 2-3 minutes, view more

A fatal accident took place at an onshore processing facility for slop water from the offshore petroleum industry.

Drilling fluids, or mud, are typically oil-water emulsions consisting of base oil (continuous phase), water (dispersed phase), and emulsifying agents. Used drilling mud, or slop, is mud enriched with water and rock cuttings from drilling --- typically 60-80% water, 10-20% emulated base oil, and 10-20% rock cuttings. The used drilling fluids are collected in slop tanks on oil platforms and later shipped to onshore facilities for further processing.

On the day of the accident, two operators were trying to remove the lid from a manhole on top of a 1600-cubic meter storage tank. However, they were not able to unscrew the rusted bolts holding the lid in place, and view more

During start-up operation of a high-temperature, high-pressure plant using hydrogen, hydrogen gas leaked from the flange of a heat exchanger and a fire occurred. The leakage occurred for two reasons:

Insufficient tightening torque control was carried out during hot-bolting and an unbalanced force was generated across the bolts.
A temperature rise was induced across the heat exchanger as a result of a revamping activity, during a turnaround shutdown.

Hot-bolting: In equipment and piping that operate at high temperatures, as the temperatures rise, the tightening force decreases, thus re-tightening of bolts is necessary. This work is called hot-bolting. The design conditions of the evaporator where the fire occurred were 2.4 MPaG, view more

Incident Synopsis
A H2 delivery truck accident occurred on a highway. The truck was pulling a trailer containing gaseous H2. Upon entering a sharp curve, the truck and trailer started to weave and pushed to the side of the road. The truck and trailer rolled about 40 feet downhill; the trailer rolled over 1 1/2 times and the tractor once, ending in the upright position with the driver still in his seat. The truck was completely totaled, but little damage was incurred by the trailer. The trailer shell was satisfactory with normal venting through the stack. The rear cabinet doors were warped shut.


The accident occurred on a bad road, which was steep with many sharp curves. The driver was going too fast for the road conditions and the type of trailer being view more

Incident Synopsis
While attempting to replace a rupture disk in a liquid H2 vessel, H2 gas was released and ignited. In fighting the fire, liquid N2 was sprayed onto a second liquid H2 vessel located nearby. This resulted in cracking of the outer mild steel vacuum jacket. The loss of the vacuum caused a rapid increase in pressure and rupture of the burst disk of the second vessel. H2 boiled off and was burned in the fire.

The rupture disk was being replaced with a load of liquid H2 in the vessel and no separating inerting gas. The H2-air mixture was probably ignited by static discharges. Rupture of the second vessel burst disk was caused by the low-temperature exposure of the mild steel vacuum jacket.

Incident Synopsis

A hydrogen explosion occurred in an emergency battery container used to transfer fuel elements. The container had five emergency power batteries. Damage was incurred by the explosion.


The H2 concentration in the container increased because the battery charger had been left on charge. In addition, the container was placed in an un-ventilated airlock. Ignition of the H2-air mixture was believed to be caused by the relays and micro switches activated when the airlock door was opened.

Incident SynopsisDuring shipping preparation operations, out-gassed hydrogen/oxygen from a recently discharged silver/zinc battery in a hermetically sealed drum was ignited. Ignition was caused by a spark generated by the scraping of the battery against the side of the drum. An explosion occurred, blowing the lid from the drum, charring desiccant bags within the drum, and causing other damage.CauseThe cause of the incident was inadequate handling/transporting/storage techniques. The battery was placed in the drum too soon after discharge.

A hydrogen explosion occurred in an Uninterruptible Power Source (UPS) battery room. The explosion blew a 400 ft2 hole in the roof, collapsed numerous walls and ceilings throughout the building, and significantly damaged a large portion of the 50,000 ft2 building. Fortunately, the computer/data center was vacant at the time and there were no injuries.

The facility was formerly a large computer/data center with a battery room and emergency generators. The company vacated the building and moved out the computer equipment; however the battery back-up system was left behind. The ventilation for the battery room appeared to be tied into a hydrogen monitoring system. The hydrogen sensor was in alarm upon emergency responders arriving at the scene (post-explosion). 911 callers view more