REACTIVE CHEMICALS INCIDENT

On December 29, 2023, at 1:45 p.m., a storage tank exploded, creating a fire at a facility in Connecticut. The explosion and fire seriously injured one contractor and the property damage was approximately $5.8 million.

The company's investigation found that a 10,000-gallon epoxy-lined steel storage tank exploded from a chemical reaction inside the tank. At about 1:00 p.m. on the day of the incident, workers finished transferring about 4,000 gallons of organic material containing methylene chloride, tetrahydrofuran, toluene, xylenes, trimethylbenzene, and naphthalene into the storage tank from another vessel at the facility. Chemical compatibility testing was not performed before making this transfer. The company's investigation concluded that adding 4,000 gallons of material to the storage tank agitated the existing 6,000 gallons of sludge already inside the tank, starting an unintended chemical reaction.
The sludge contained hydrogen peroxide, organic peroxides, and metal ions, including cobalt, iron, nickel, and chromium. Agitating this material likely started a chemical decomposition reaction between the organic and peroxide components in the presence of metals. This reaction produced vapor (including oxygen gas) and generated heat. At 1:45 p.m., the flammable vapor within the hot tank ignited (autoignition), and the storage tank exploded. The explosion created a fire that seriously injured a truck driver who was at the facility to make a chemical delivery into a different tank.
The company  did not estimate the amount of combustion products released when the storage tank exploded. To prevent a similar incident, The company stated that the company plans to stop handling oxidizers in this equipment, perform compatibility testing before transferring materials, and routinely clean its tanks.

Probable Cause
Based on The company's investigation, the CSB determined that the probable cause of the incident was the mixing of reactive chemicals within a storage tank, which generated heat and oxygen. The heat from the reaction ignited the flammable vapor in the tank (autoignition), resulting in the explosion. The failure to confirm chemical compatibility before transferring material into the storage tank contributed to the incident.
Source:CSB.gov

BE CAREFUL WITH EXPLOSIVE MIXTURES

 On October 13, 2023, at approximately 9:45 a.m., a mixture containing tetrazine and lead styphnate detonated at a facility in Nebraska. The explosion fatally injured one operator.

At the time of the incident, the company was producing priming compound, the ignition component used in firearm ammunition. The priming compound had already completed the first mixing cycle, and the operator was scraping the partially mixed priming compound off the mixer blade and the sides of the mixing bowl with a silicone spatula. While performing this task, the priming compound detonated and fatally injured the operator.
The company’s investigation evaluated the possibility that the explosion was ignited by static electricity. The explosive material’s moisture content was within the proper range, and the spatula, the room floor, and the operator’s shoes passed a conductivity check before the incident occurred. The company’s investigation concluded that these conditions showed that the explosive material should have been adequately desensitized, making static electricity an improbable ignition source. Instead, the company’s investigation concluded that the detonation was most likely ignited by the energy applied from mixing a dry area of explosive mixture with the silicone spatula.
After the incident, the company eliminated the need for operators to scrape the bowl and mixer blade until the entire mixing stage was completed, limiting the time that an operator was near the unmixed explosive components.

Probable Cause
Based on the company’s investigation, the CSB determined that the probable cause of the detonation was the energy applied by manual mixing to the explosive mixture.

Source: CSB.gov

ON THE 41ST ANNIVERSARY OF BHOPAL - WHERE IS PSM IN INDIA?

Tonight is the 41st Anniversary of the Bhopal Disaster. What is the status of PSM in India? Have we learnt the lessons? My take:

GOVERNMENT AND LAWS:

Till today, there is no specific legislation in PSM in India. The oil and gas industry OISD-GDN- 206 specifies guidelines to be followed. There is talk about bringing in PSM legislation but I have not heard of anything released till now.

INVESTIGATION OF INCIDENTS AND PUBLIC SHARING OF REPORTS:

There is still a shroud of secrecy when any incident investigation is carried out by an expert committee. The results are still not shared publicly. The Sigachi industries  blast investigation report is mentioned in an article in the Hindu newspaper "Though the report was submitted to the government in September, it has not been publicly shared nor has any action been initiated against the company management".

Read the article in this link: 

https://www.thehindu.com/news/national/telangana/sigachi-report-production-enhancement-without-trained-staff-and-safety-measures-led-to-the-explosion/article70307963.ece

Unless we share and learn for incidents, we will not be able to prevent another incidents. "There are no new incidents".

The number of incidents of gas/chemical leakage from Government data presented in parliament for 2018 to 2022 is given below (Source:  https://www.data.gov.in/resource/state-wise-number-data-received-chief-inspector-factories-cifs-gas-chemical-leakage)

The LG Polymer gas leak incident in Visakhapatnam occurred in May 2020 in AP. 

 

 INDUSTRY:

A lot of progress has been made in the large chemical process industries regarding PSM. All the large players in the industry (Public limited) and major private sector players have implemented either the OSHA 14 element PSM system or the 20 element risk based PSM system of CCPS.

Industry bodies like ICC, FICCI, FAI, CCPS etc have raised awareness of PSM by seminars and workshops.

There is a lot of activity going on in AI and ML and other technologies but the leadership must realize that these are only tools that can act as enablers. Hard decisions need to be taken by management who are competent in process safety. There is a lack of Process Safety competency requirements for directors on the boards of chemical processing industries. 

 ACADEMIA:

Academia in India is now offering more courses in process safety. Recently IIT Madras has started a PG diploma in process safety. See the link https://code.iitm.ac.in/processsafety 

WAY FORWARD:

Presently, the improvements in PSM in India are being carried out in Silos. The government must involve Industry, Academia, subject matter experts and public bodies to chart out an integrated approach towards improving process safety in India. Investigation and sharing of lessons learnt from fatal incidents should be made publicly and centrally available. 

 

 

 

 

 

COMMUNICATION IS VERY IMPORTANT WHEN A JOB IS RESUMED AFTER A TIME GAP

On May 23, 2023, at about 8:20 a.m., approximately 60,000 pounds of naphtha were accidentally released at a refinery Oklahoma. The released naphtha vaporized and ignited within seconds of the initial release. The fire fatally injured one employee and seriously injured another employee. The company estimated that the incident resulted in approximately $8 million in property damage.

The company's investigation found that a flow control valve (“control valve”) in the naphtha hydrotreating unit was malfunctioning. On May 22, 2023, the day before the incident, two maintenance employees were assigned to troubleshoot the control valve. The maintenance team conducted a walkthrough with an operator, who issued them a safe work permit. Operators bypassed flow around the control valve to maintain the desired flow rate to downstream equipment. An operator also closed the isolation valve upstream of the control valve. The isolation valve downstream of the control valve remained open, however, and the drain valves on each side of the control valve remained closed. As a result, the equipment contained flammable liquid naphtha, which the company did not isolate, lock out, or otherwise prepare for equipment opening work.
The control valve was opened from its closed to its fully open position, and the maintenance employees concluded that it was “hung up” and not working correctly. The maintenance employees planned to disassemble the valve and confirmed that there was a gasket set for it. With the workday nearing its end, the company personnel decided that the control valve work could continue the next workday while the control valve remained bypassed overnight.
On the day of the incident, the same maintenance employees returned to continue working on the control valve. A different operator authorized the maintenance employees to use the same safe work permit from the previous day. The operator understood that the scope of work was limited to troubleshooting the control valve. Consequently, no field review of the job took place. About 15 minutes after the maintenance employees returned to the work location, naphtha began releasing from the control valve’s bonnet flange.

The flame in a nearby fired heater likely ignited the flammable hydrocarbon vapor. The fire engulfed the two maintenance workers, but they escaped the area. Emergency responders transported the two workers to hospitals by helicopter, where they were admitted for treatment of their serious burn injuries. Three days later, on May 26, 2023, one of the workers succumbed to their injuries and died.
The investigation revealed that six of the eight nuts had been removed from the control valve’s bonnet flange, which was the typical practice at the refinery when preparing to access the internal components. The control valve’s bonnet flange had been partially disassembled while its downstream isolation valve was open, and it contained naphtha at 250 pounds per square inch gauge pressure and 425 degrees Fahrenheit. It is unknown whether the maintenance employees thought the system was safe to disassemble the control valve or did not recognize the hazard of disassembling the pressure-retaining components.

Probable Cause
Based on the company's investigation, the CSB determined that the cause of the incident was disassembling a control valve’s pressure-retaining bonnet flange during a maintenance activity. The control valve was not isolated from the operating process before performing this work.
Miscommunicating the scope of the work or not recognizing the hazards of disassembling the control valve’s pressure-retaining components led to safe work (energy isolation) practices not being performed, which contributed to the incident.

Source:CSB.gov

ARE YOU CARRYING OUT VIBRATION ANALYSIS FOR ROTATING EQUIPMENT TO PREDICT FAILURES?

On May 15, 2023, at 9:32 a.m., an accidental release of naphtha caught fire, fatally injuring one worker at a Refinery in Texas. The company estimated that this event resulted in $829 million in property damage.
On the morning of the incident, two employees were completing an equipment oil change on an elevated platform above a pump that was supplying naphtha to downstream equipment. The pump’s coupling failed, reducing outlet flow and creating high vibration that broke a small bore (¾-inch) piping section, releasing flammable naphtha. Employee 1 was on the platform cleaning up the work area while Employee 2 was carrying a bucket of oil down the stairs from the platform. Employee 2 smelled the released hydrocarbon and saw what looked like a steam cloud. Within minutes of the release, the flammable vapor ignited 

The heat from the fire ruptured piping and damaged other equipment. Employee 2 was able to exit the unit before the flammable naphtha ignited. Employee 1 did not escape from the elevated platform and was fatally injured by the fire.
The company's investigation found that a pump inspection in June 2022 had identified damage to the coupling of the pump but did not recommend any repairs. During the release in this incident, the pump’s motor continued to operate and spin the damaged coupling. The heat generated by the friction ignited some of the released naphtha, resulting in the fire. The investigation also found that according to the company’s mechanical integrity program, vibration analysis should be performed every two months to predict pump failures, including coupling failures. The last vibration analysis test on the pump was completed in October 2022, seven months before the incident. The company reported that approximately 102,000 pounds of naphtha and light hydrocarbons were released.

Probable Cause
Based on the company's investigation, the CSB determined that the probable cause of the incident was a pump coupling failure that created high vibration, breaking a section of small-bore piping and releasing flammable naphtha. With the pump’s motor continuing to operate, the coupling failure also created enough heat (friction) to ignite some of the released naphtha vapor, creating the fire.
The company's mechanical integrity program contributed to the incident by not repairing the damaged coupling identified by the inspection. Additionally, the company did not perform its required vibration analysis on the pump, which could have predicted the coupling failure. 

Source:CSB.gov