Thermal expansion of DMS caused incident

At 11:30 a.m. on June 20, 2007, Employees #1, #2, #3, and #4, who worked for Scaffolding Company, and Employees #5, and #6, who worked for Plant Services Company, and Employees #7 and #8, who worked for a chemical manufacturer, were hospitalized after being exposed to dimethyl sulfate (DMS) in the ethoxylation area where it was used in reactors 4 and 5. 

Employee #7 was an operator who moved bags containing chemicals into the area in order to add it to reactor 4. Employee #8 was a mechanic that worked unplugging an auger at reactor 4. Employees #7 and #8 started working at 7 a.m. at reactor 4. 

Employees #1, #2, #3, and #4 dismantled a scaffold at a platform at the reactors. 

 Employees #5 and #6 removed and installed new insulation on piping at a platform at the reactors. The host employer did not become aware that employees were exposed to DMS until about 2 p.m., when workers were discovered having chemical burns. Employees worked on a raised platform around the two reactors. In order to enter and leave the area, they walked along a path between two the reactors that was only 30 inches wide, and a pipe that contained DMS which ran overhead between the reactors. The piping system normally operated at 5 psi, but thermal expansion of DMS caused pressures over 300 psi and caused a valve on the overhead pipe to leak this extremely hazardous compound down onto employees that worked beneath the pipe. 

Source:OSHA.Gov

Turbine exhausts are HOT!

 On April 5, 2012, Employee #1 was handling an exhaust leak from a turbine on the site of a power plant. The task involved the placement of a piece of insulation blanket over the pipe expansion bellow system, which contained the exhaust leak. The leak was of hot air, which was approximately 600 to 700 degree F. It was emanating from a section of pipeline located on the exhaust waste heat recovery system. While Employee #1 was dealing with the leak, he inhaled the hot air exhaust and injured his lungs. He was transported to a medical center. At the medical center, Employee #1 underwent treatment and was hospitalized. 

 

Source:OSHA.Gov

Asphyxiation incident during installation of a PSV

 At 11:30 a.m. on October 15, 2021, Employees #1 and #2, both maintenance employees, were assigned to install a pressure safety valve (PSV) on a flare header in a methylene diphenyl diisocyanate (MDI) unit when they were exposed to nitrogen and carbon monoxide. The installation procedure requires supplied air respirators. The employees were staging equipment on the platform area in the MDI unit to remove the PSV. Employee #2 decided to go down to the lower level to obtain both employees a supplied air respirators before starting the work. Employee #2 looked back and saw Employee #1 slumped over on the platform. Employee #1 was overcome with the gases and loss consciousness. Employee #2, in an attempt to revive Employee #1 also loss consciousness. The employees were discovered by coworkers and emergency services were notified. First responders removed both employees from the platform but Employee #1 died from his exposure.

Source:OSHA.gov

Are you discussing domino effects in your HAZOP?

At approximately 5:50 p.m. on March 25, 1988, the leacher autoclave (#2) in building #1, which had been in service for about three weeks, reached a temperature of about 490 degrees Fahrenheit and a pressure of 400 psi. At this point the single locking (locating) pin sheared (the second pin was missing) allowing the cover to rotate against the locking ring, which was not fully engaged. The cover was released with explosive force, tearing a large hole in the roof and rupturing a 2 in. high-pressure gas line. As the head fell, a second hole was made in the roof about 25 yards northwest of the original location. Approximately 120 gallons of 28 percent sodium hydroxide solution was instantly vaporized into a cloud of caustic fumes that drifted over the area, causing eye, lung, and throat irritation to approximately 25 people, including the police who responded to the emergency. Employees #1 through #12 required medical attention. The gas line was promptly shut off by plant maintenance personnel who responded to the explosion. This action prevented further serious fire and explosion damage and possible loss of life.

Source: OSHA.gov

HAPPY NEW YEAR!