A person working in a hydrogen lab unknowingly closed the wrong hydrogen valve and proceeded to loosen a fitting in one of the hydrogen gas lines. The pressure in the 1/4"-diameter hydrogen line was approximately 110 psig. Hydrogen escaped from the loosened fitting and the pressure release resulted in the tubing completely detaching and falling to the floor. The person noted seeing a white stream around the hydrogen jet leak. The person noted a color change and noise change as the leak ignited (this happened in a matter seconds and he did not have a chance to react). The person left the lab and pushed the emergency stop button. Someone else pulled the fire alarm. Both of these actions were designed to close the main hydrogen solenoid (shutoff) valve. The local emergency response view more
An apprentice mechanic lacerated his right forearm while quickly sliding out from under a hydrogen prototype bus when the bus slipped off a hydraulic jack. The apprentice and another mechanic had raised the bus about 1 foot from the ground to position it on jack stands when the hydraulic jack tipped over. The apprentice went to the site medical facility, where he needed five stitches to close the wound in his forearm.
The mechanics were raising the rear of a hydrogen prototype bus, like the one in the figure below, and placing it on jack stands. After chocking the wheels, they used bottle jacks on each side of the rear axle to raise the bus high enough to place a 20-ton hydraulic jack under the differential. With the bus resting on a pair of small jack stands, they raised the view more
The over-pressurization of a laboratory ball mill reactor designed for operation under slightly elevated pressures resulted in a serious injury. The apparatus had been routinely operated under argon and hydrogen pressures of 5-10 atmospheres for nearly two years. The apparatus had not been tested for operation at pressures greater than 10 atm.
A visiting intern, frustrated in attempts to hydrogenate magnesium silicide through ball milling in the previously noted pressure range, attempted to perform the operation at higher pressures. The approximately 70-ml reactor was loaded in a glove box with 0.5 g of magnesium silicide and six milling balls. Upon pressurization to 80 atmospheres, a 270-degree rupture occurred around the perimeter of the reactor. The blow-out of the reactor view more
One man was killed and another severely injured while working with a portable battery power supply.
At a test facility, a water-submersible portable battery power supply was used to power lighting. The battery power supply contained two 12-volt lead-acid automotive batteries, a wiring harness, and switching relays mounted in an air-tight case suitable for submersion in water. The case possessed ½-inch aluminum walls and a 13.8-pound lid. The box had been used periodically over two years.
After charging all night, the battery power supply was moved into place and connected to the lighting. Two technicians started to test the unit. One technician rested his hand on the case lid while the second leaned over the lid and threw the switch to activate view more
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