Dolco Packaging - Wenatchee - Executive Summary
The Dolco Packaging facility in Wenatchee, Washington produces extruded polystyrene foam products using butane as the expanding agent. The facility consists of manufacturing areas, storage warehouses, and offices, with a butane storage tank located outside of the buildings. The facility operates as much as 24-hours per day, 365 days per year and employs approximately 140 people. Our foam products are used in products such as egg cartons and food packaging trays.
Butane is the only material at the facility subject to the United States Environmental Protection Agency's (USEPA's) Risk Management Plan (RMP) program. Butane is received by Dolco as a liquid in tank trucks and is unloaded into a storage tank located outside that was installed in 1995. The maximum butane storage quantity is 88% of the tank design capacity to allow room for emergency expansion under emergency situations. Butane is pumped through a controlled system into the foam productio
n building. The butane is then used to expand melted plastic within the extruders to create the desired foam product. A number of valves, controllers, and instruments control and monitor the pressure and flow of the butane throughout the process.
The primary hazards associated with the butane system are releases that could occur outside or inside the extrusion building that could lead to a fire or explosion. The possible causes of releases include pump failure, failure of piping or tubing, failure of valves or instruments, storage tank leakage, or failure of equipment used for tank filling.
Five Year Accident History
The facility has not experienced any significant accidents associated with handling butane in the last five years. A significant accident would be one causing some type of off-site impact or on-site injuries or significant property damage.
USEPA accident prevention regulations require companies to analyze what is defined as a worst-case rel
ease scenario. For Dolco, the worst-case scenario as defined by the USEPA is the sudden loss of containment of all of the butane contained in the aboveground storage tank. This would mean some type of catastrophic failure of the tank. RMP regulations require the assumption that the numerous safety and alarm systems Dolco has in place fail to operate as designed. It is also required to assume that this hypothetical release occurs during the least likely weather conditions, meaning very low wind speeds and a stable, or stagnant atmosphere. This worst-case scenario therefore assumes that several highly unlikely events occur simultaneously:
-Catastrophic failure of the butane tank.
-All of the automated safety and alarm system fail to operate.
-Failure of our trained operators to respond appropriately.
-The event occurs during the least likely meteorological conditions.
While this event is highly unlikely, we are required to analyze such a release and to estimate the potential effec
t on the surrounding community. Dolco used a state-of-the-art model to estimate the effect of this hypothetical release, the Baker-Strehlow Model a commercially available model in the Breeze Haz Fire/Explosion software program. The model predicts the distance to which an explosion or blast wave equivalent to one pound per square inch (psi) would reach. One psi overpressure is set by the USEPA as the point of concern for materials presenting a potential explosion hazard. An overpressure of one psi would typically shatter windows, but not cause serious structural damage to buildings. The butane worst case scenario results show that there are no off-site buildings, commercial or residential, or other public receptors within the one psi zone.
Release Prevention Program
Dolco's Plant Manager has the overall responsibility for ensuring that the facility operates in a safe and reliable manner. This responsibility includes overseeing the implementation of the RMP. To ensure that the r
isk management program is appropriately developed and implemented, the Plant Manager has assigned the role of RMP Coordinator to a staff member with the necessary background, training, and experience. The RMP Coordinator, acting with the authority delegated directly from the Plant Manager, has the responsibility for the development and implementation of the RMP.
Dolco Packaging has invested significant manpower and resources to prepare and implement this RMP and the related Process Safety Management (PSM) program to address the potential hazards associated with butane at the Wenatchee facility. The facility's RMP/PSM program contains a Prevention Program that focuses on prevention of releases. The Prevention Program includes the use of appropriate equipment design standards, safety valves and instruments, written operating procedures, employee and contractor training, regular equipment inspection and maintenance, and periodic program auditing to reduce the likelihood of butane rele
ases occurring. The facility has compiled process safety information and has conducted a process hazard analysis (PHA) review of the butane system. The butane storage tank was designed and constructed in accordance with the American Society of Mechanical Engineers (ASME) code for pressure vessels. The butane system was designed and constructed in accordance with the applicable portions of the National Fire Prevention Association (NFPA) 58 LP-Gas Code and is equipped with a variety of modern safety equipment.
The facility has implemented administrative controls and procedures to aid in the prevention of releases from the operation of the butane system. Personnel operating and maintaining the butane system undergo regular training. The training program includes initial training as well as periodic refresher training and training updates when major process or equipment changes are made. Written operating procedures are used to standardize the procedures for startup, normal operat
ion, normal shutdown, and emergency shutdown. Tank loading is conducted by contract truck drivers certified to safely handle LP-gases and monitored by trained Dolco Packaging personnel. The facility conducts regular planned inspection and preventative maintenance of the butane system equipment.
Release Detection and Emergency Response
The plant has 30 gas detectors located throughout the facility. The detectors are designed to warn an operator of a potential butane release. These include gas detectors on relief valve vent lines to indicate when a safety relief device has activated. Automatic sprinkler systems are located throughout the building areas where butane is present. The facility has organized an Incipient Fire Brigade which manages emergency response in the event of a leak, fire, or explosion. The Fire Brigade is responsible for evacuation of employees, notification of local emergency services, safe and complete shutdown of equipment if needed, rendering first aid to
injured employees, and locating, containing, and extinguishing fires (within the guidelines of NFPA 600 1-4.3.1 defining incipient fires). The facility has coordinated with the City of Wenatchee Fire Department with regard to emergency response on the butane system. For additional information on what actions to take in the event of an emergency, contact the City of Wenatchee Fire Department.
Additional Steps to Improve Safety
Dolco has created a culture for continuous improvement of its safety systems and programs. We have trained our employees to safely perform their assigned tasks. We also encourage our employees to suggest changes or improvements that will help to increase the safety of the facility. We perform inspections and preventative maintenance to minimize the potential for unanticipated failure of our equipment. Our systems and programs are audited, typically by an outside company, at least every three years to evaluate their effectiveness.
We have recently revie
wed and modified elements of our Prevention Program. The entire RMP/PSM program is updated and audited on a regular basis with a focus on continuous improvement of all elements of the program. As a result of the ongoing review and improvement of butane safety systems at the facility, capital improvements will be made to the high-pressure pump room, including the installation of new or improved fire walls, fire doors, explosion-proof lighting, and ventilation.