Rayan Al-Shehri’s Post

Transcript

November 13th, 2020 Volcker Polysilicon North America in Charleston, TN. One worker was killed and two others were seriously injured when attempting to escape a hydrogen chloride gas release. An additional worker was injured from exposure to the hazardous hydrogen chloride. On the morning of November 13th, Vacker issued a work permit to Jake Marshall to perform maintenance on a heat exchangers vapor outlet piping. The work was to be done while hydrogen chloride was actively flowing through the piping. Exposure to hydrogen chloride gas can cause injuries ranging from irritation of the eyes and lungs to severe burns or death. To protect themselves from those chemical hazards that Jake Marshall contractors wore full body chemical resistant suits, rubber boots and gloves, and full face respirators with acid gas cartridges. The maintenance took place on the 5th floor of an equipment access structure which only had one staircase for entry and exit. That morning, contractors from Penn Golf were also working on the same 5th floor platform. The Pen Golf employees, however, were performing insulation activities that were not expected to involve potential exposure to hydrogen chloride. For their insulation work, the four Pen Golf contractors were wearing the minimum personal protective equipment required by Volcker flame resistant clothing, steel toe safety boots, as well as safety glasses and hard hats. They had escape respirators and safety harnesses in their possession but were not actively wearing those items. The Jake Marshall contractors task was to tighten bolts on the heat exchangers vapor outlet piping in order to minimize leaks. The amount of force required to tighten the bolt is based in part on the materials of construction of the equipment being connected. The amount of force is called the torque requirement. The vapor outlet piping included both a nozzle. Made of graphite and lined piping. Constructive carbon steel. In this case, the torque requirement for bolts connecting steel to steel is higher than the torque requirement for bolts connecting steel to graphite, as graphite is a very brittle material. But on the day of the incident, Jake Marshall pipe fitters were not given written specifications for every bolt they would tighten. A Jake Marshall Journeyman provided an apprentice pipe fitter with a torque wrench set to 40 foot pounds, which is the setting for tightening the steel to steel connections. After tightening the bolts requiring 40 foot pounds of torque, the pipe fitter then used the torque wrench to tighten bolts on the steel to graphite connection, but the manufacturer recommended torque value for those bolts is only 15 foot pounds. As a result, the bolts were inadvertently overtightened at 10:04 AM. The excess torque applied to those bolts caused the heat exchanger to crack hazardous hydrogen chloride released to the atmosphere. Between the workers and the only available staircase, within 15 seconds, a large hydrogen chloride cloud filled the area, preventing the workers on the platform from seeing their surroundings. The Apprentice pipe fitter quickly moved away from the release. As he did, his chemical suit became entangled on surrounding equipment and tore open. This exposed him to a hydrogen chloride, which caused chemical burns. In the chaos, he bumped into equipment on the platform. Which knocked off his respirator. Although he was located closest to the staircase without a respirator, he could not pass through the hazardous cloud to exit. Instead, he moved to the opposite side of the platform where the other contractors had been working. Three of the four Penn Golf employees put on their escape respirators, but without chemical suits, they were unable to walk through the cloud to reach the staircase located on the opposite side of the platform instead. They attempted to climb down piping on the side of the structure, which was approximately 70 feet high. While climbing down, all three fell to the ground. One worker was fatally injured from the fall and two sustained serious injuries. The remaining Penn Golf worker was able to put on her escape respirator with help from a Jake Marshall worker who, wearing chemical resistant PPE, also attempted to shield her from the hazardous hydrogen chloride. The dangerous release continued for approximately 3 minutes until all the gaseous hydrogen chloride had escaped from the system. After the release stopped, the three Jake Marshall workers and one Penn Golf worker used the staircase to evacuate. The area and safely reach the ground.