A petroleum refinery experienced a catastrophic rupture at one bank of three heat exchangers in a catalytic reformer/naphtha hydrotreater unit because of high temperature hydrogen attack (HTHA). Hydrogen and naphtha at more than 500F were released from the ruptured heat exchanger and ignited, causing an explosion and an intense fire burned for more than three hours.

The rupture fatally injured seven employees working in the immediate vicinity of heat exchanger at the time of the incident. The workers were in the final stages of a start-up activity to put a parallel bank of three heat exchangers back in service following cleaning. Such start-up activities had resulted in frequent leaks and occasional fires in the past and should have been considered as hazardous and nonroutine. view more

A chemical plant experienced a valve failure during a planned shutdown for maintenance that caused hydrogen to leak from a valve and catch fire. Four chemical reactor chambers in series were being emptied of liquid using hydrogen gas as part of a maintenance procedure. Two heater valves were opened allowing 3000 psi hydrogen to flow in reverse direction to purge the reactor system for approximately 25 minutes. At completion of the purging process, a "light" thud was heard as the reactor empty-out valves are being closed. Smoky vapor was observed coming out of one of the reactor empty-out valves and the valve closing was stopped by the operator. The operator summoned a second operator for help at which time a second "loud" thud was heard with a much larger light and view more

A pressure relief device (PRD) valve failed on a high-pressure storage tube at a hydrogen fueling station, causing the release of approximately 300 kilograms of hydrogen gas. The gas ignited at the exit of the vent pipe and burned for 2-1/2 hours until technicians were permitted by the local fire department to enter the station and stop the flow of gas. During this incident the fire department evacuated nearby businesses and an elementary school, closed adjacent streets, and ordered a high school to shelter in place.

There were no injuries and very little property damage. The corrugated roof on an adjacent canopy over a fueling dispenser was slightly singed by the escaping hydrogen flame, causing less than $300 in damage.

The station's operating systems worked as view more

Overview: A hydrogen leak and explosion occurred due to the installation of an incorrectly sized gasket at the suction line of a hydrogen compressor in a refinery hydrodesulfurization plant. The incorrectly sized gasket was mounted during the startup of the plant in 2001 and had never being inspected nor replaced.

Incident synopsis: The operating conditions were stable when the operator received an alarm indicating pressure loss in the circuit. He immediately instructed his field personnel to inspect the area. The hydrogen leak was confined inside the compressor room because the walls and roof were not provided with ventilation devices. An explosion occurred, causing two fatalities and the destruction of the compressor room and some of the surrounding area.

The bulkhead between a liquid hydrogen tank and a liquid oxygen tank failed due to a series of events. Air services to the building were shut down for repairs and the facility had switched to an emergency nitrogen supply. Failure to switch back to service air when it became available, led to the mishap.

The emergency supply became depleted and two valves in the normal nitrogen purge system failed in the open position, releasing the high-pressure nitrogen gas from the manifold into the liquid hydrogen tank. The gas flow raised the liquid hydrogen tank pressure to 4.5 psig. That was sufficient to rupture the bulkhead wall.

A laboratory technician died and three others were injured when hydrogen gas being used in experiments leaked and ignited a flash fire.

The incident occurred in a 5,700-square-foot, single-story building of unprotected non-combustible construction. The building was not equipped with automatic gas detection or fire suppression systems.

Employees in the laboratory were conducting high-pressure, high-temperature experiments with animal and vegetable oils in a catalytic cracker under a gas blanket. They were using a liquefied petroleum gas burner to supply heat in the process.

Investigators believe that a large volume of hydrogen leaked into the room through a pump seal or a pipe union, spread throughout the laboratory, and ignited after coming into contact with the view more

An employee at a soap manufacturing plant died in a flash fire outside the facility's hydrogenation building. Responding personnel encountered a fire at the base of the plant's hydrogen storage towers, and they found the victim, who was burned over 90 percent of his body, some 50 feet away.

Officials determined that a pipe connection failed and that hydrogen, pressurized at 1,800 psi, ignited when it was released into the atmosphere, killing the plant operator.

According to reports, the pipe connection failure stemmed from pressures higher than design tolerance, which in turn were the result of over tightening that occurred during routine maintenance replacement. The new bolts were stronger than those they replaced, and the threads of the nuts had been partially view more

SummaryA fire occurred in a battery manufacturing plant that was about to cease operations for the night. The fire caused an estimated $2.4 million in property damage when an electrical source ignited combustible hydrogen vapors.BackgroundThe incident occurred in the forming room, where wet cell batteries were stored for charging on metal racks. The facility had a wet-pipe sprinkler system, but no automatic hydrogen detection equipment.Incident SynopsisAt 11:52 pm, a security guard on patrol noticed a free burning fire in the forming room and notified the fire department. It took fire fighters almost three hours to bring the fire under control.Although the facility was equipped with a wet-pipe sprinkler system, the forming room's branch had been disconnected 10 to 15 years before view more

Incident Synopsis
During a standard testing procedure, a 3,000 psig relief valve actuated at normal line pressure, releasing gaseous H2. The gaseous H2 combined with air, resulting in an explosion which damaged the test facility.

Cause
The relief valve was improperly set to open at line pressure, and the inspection was inadequate in that it didn't identify this error. Contributing cause was poor design of the venting system, which was installed in a horizontal position, causing inadequate venting and buildup of static electricity.

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.

Cause
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.