ARE YOUR CRITICAL ALARMS SET CORRECTLY?

On March 14, 2023, at 11:40 a.m., approximately 1,000 pounds of flammable hydrocarbons were accidentally released from a pump seal and ignited (autoignition) at a Refinery in Texas, causing a fire.      The company estimated the property damage from the incident to be over $1 million.                        

During the unit startup approximately five days before the incident, the pump (a centrifugal pump) had operated with low suction (inlet) pressure for nearly two hours due to a low liquid level in the upstream equipment. The low suction pressure caused the pump to cavitate, which vibrated the pump and damaged the pump’s bearings. Five days later, on March 14, the damaged bearings and the resulting stress on the pump’s mechanical seal caused the seal to fail. The hot hydrocarbons within the pump were released into the atmosphere and ignited, causing a fire. The material was released at 590 degrees Fahrenheit (°F) and had an autoignition temperature of 484 °F.
 In addition, on March 11, two days after the unit startup, vibration from the damaged pump triggered a “High Priority Alarm.” The refinery’s usual responsive action to high-priority vibration alarms was to switch pumps. However, the company did not have another pump available and continued to operate the installed pump, as refinery employees believed the pump was still safe to operate. Employees anticipated that a replacement pump would be available on March 13, but the pump was not replaced before the incident on March 14.
Although the pump vibrations continued and worsened, they never triggered the “Critical High High” vibration alarm threshold because the alarm was programmed incorrectly. Had the vibration alarm been programmed correctly, the “Critical High High” alarm should have activated on March 12, two days before the incident.
The company's investigation found that the refinery operators mistrusted the pump vibration alarms due to past nuisance alarms, causing employees to normalize these alarms.

Probable Cause
Based on the company's investigation, the CSB determined that the probable cause of the incident was the release and ignition of hydrocarbons from a failed pump that had been damaged after it cavitated during a unit startup. Contributing to the incident were unit startup conditions that damaged the pump, incorrectly programmed alarms, and employee mistrust of alarms.

Source: CSB.gov

INCORRECTLY CONNECTED HOSE CAUSES INCIDENT

 On February 21, 2023, at 10:15 p.m., an unknown amount of propane was accidentally released, seriously injuring a temporary employee at a facility in California.
A temporary employee had moved a propane-fueled forklift to the facility’s filling station to refuel its tank. He connected the filling station’s hose to the forklift’s tank and opened the valve to start the propane flow. The hose connection was not secure, and propane immediately discharged into the atmosphere. The employee tried to either tighten or remove the hose during the release. As a result, the cold propane sprayed and cryogenically burned him. The temporary employee was not wearing personal protective equipment (PPE) that could have protected the employee from being exposed to cold propane.

There was no documentation that the temporary employee had been trained on safely filling propane tanks, although another employee stated that the temporary employee had been trained. The company's investigation found that site training on refilling propane fuel tanks did not include information on items to inspect before beginning the filling operation.
Probable Cause
Based on the company's investigation, the CSB determined that the probable cause of the accidental release of propane was not securing the hose connection before starting the filling operation. Not using personal protective equipment that could protect the employee from being exposed to cold propane contributed to the severity of the incident.

Source:CSB.gov

IMPROPER OPERATION READINESS REVIEW DUE TO HUMAN FACTORS CAUSED AN INCIDENT

 On February 23, 2023, at 8:15 p.m., an accidental release of approximately 164 pounds of hydrocarbons (pentane and heavier hydrocarbons) occurred at a Refinery in Texas. The hydrocarbons were released from an open bleed valve on a crude unit heat exchanger during startup. The hot hydrocarbons ignited (autoignition), causing a fire that damaged nearby equipment. The company estimated the property damage from the incident to be $2.3 million.

On February 12, 2023, the crude unit heat exchangers were shut down for cleaning. Ten days later, on February 22, refinery operators prepared to put the heat exchangers back into service after the cleaning. During the day shift on February 23, they purged air from the heat exchangers to prepare it for startup.

Night shift operators then continued readying the heat exchangers for startup. They obtained the energy isolation drawing, which was used to document which valves had been locked in the open or closed position to allow for safe cleaning of the heat exchangers.
The operators walked down the equipment, removed the locks indicated on the energy isolation drawing, and ensured the valves were lined up in the correct position for startup. The operators believed they had addressed all the valves documented on the energy isolation drawing. Unknown to the operators, however, a bleed valve on top of the heat exchangers remained locked open when the lock should have been removed, and the valve should have been closed. The company's investigation report noted that the open bleed valve was not easy to locate visually, and the operators’ ability to see it may have been further impaired when it was dark outside.
As the startup sequence progressed, hot hydrocarbons sent to the heat exchangers flowed through the open bleed valve into ambient air and ignited. The material was released at 562 degrees Fahrenheit (°F) and had an autoignition temperature of 482 °F.
The company stated that the energy isolation drawing was destroyed in the fire; so it is unknown if the locked open bleed valve was shown on the drawing.
Probable Cause
Based on the company's investigation, the CSB determined that the probable cause of the incident was the release and ignition of flammable hydrocarbons when a bleed valve was inadvertently left open during an equipment startup. Contributing to the incident was a lack of a system, such as leak testing, to ensure all valves were in the correct position before the equipment was started up.

Source: CSB.gov

 

 

A LOOSE BEARING LOCKNUT CAUSES AN INCIDENT

On February 11, 2023, shortly before 1:00 p.m., a pump failure released hydrocarbons (primarily crude oil) and nitrogen oxide at a crude oil production facility in Texas. The crude oil released from the failed pump ignited, causing a fire that damaged nearby equipment and led to additional material releases The company estimated the property damage from the incident to be about $1.5 million.

The company's investigation found excessive wear and tear on the pump, which led to its failure. The company also found that the pump’s bearing lock nut, which holds the bearings in place, was loose. It concluded that this loose lock nut allowed the pump shaft to move and contact pump components, which caused pump damage that resulted in crude oil being released from the pump into the atmosphere. The company also concluded that heat from metal-to-metal contact in the pump seal area may have provided the ignition source.
During the incident, over 1,500 barrels of hydrocarbons (primarily crude oil) and over 1,200 pounds of nitrogen oxide were released.

Probable Cause
Based on the company's investigation, the CSB determined that the probable cause of the accidental crude oil release and fire was the failure of a crude oil pump. The released crude oil was likely ignited from heat from metal-to-metal contact in the worn pump.

INCIDENT DUE TO LACK OF PROPER CONTROL OF HAZARDOUS ENERGY

On January 19, 2023, less than five pounds of hot water and pulp were accidentally released, seriously injuring one employee at a paper mill in Georgia, a facility that produces paper products.
The employee had been tasked with inspecting and cleaning a pulp screen. The pulp screen equipment’s drain system had plugged (an abnormal condition), causing water and pulp to remain inside the equipment. With the plugged drain, the process conditions allowed the typically warm water to become hot.
When the employee started unbolting the equipment flange to access the screen, hot water and pulp sprayed out of the flange, contacting the employee. The employee received thermal burns requiring hospitalization. Miscommunication and ineffective training allowed the worker to open this equipment before it was effectively isolated and de-energized.
After the incident, the company added safety interlocks to shut down this equipment automatically during certain abnormal conditions.
Probable Cause
Based on the company's investigation, the CSB determined that the probable cause of the incident was opening equipment that contained pressurized hot water and pulp. Contributing to the incident was ineffective communication and training on the site’s procedure to control hazardous energy.

Source: CSB