Dolco Packaging - Decatur - Executive Summary
The Dolco Packaging facility in Decatur, Indiana 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 building. The facility operates as much as 24-hours per day, 365 days per year and employs approximately 180 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. The maximum butane storage quantity is 95% of the tank design capacity to allow room for emergency expansion under emergency situations. Butane is pumped through a controlled system into the foam production building. The butane is then u
sed 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 release scenario. For Dolco, the wo
rst-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 effect 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 residential receptors within the one psi zone, but one off-site industrial building is within the one psi zone.
Alternative Release Scenario
The chance of the worst case release scenario occurring at the facility is believed to be remote because it is expected that at least some of the protective equipment and measures will function as designed. An alternative release sce
nario has been analyzed which assumes that a bleeder valve on the butane fill line leaks during tank loading. The release duration is estimated at four minutes since Dolco's procedures require an operator to be in the immediate area during a loading operation. The operator would detect the release and immediately stop the transfer using emergency shutdown switches, thereby stopping the release. Under this alternative release scenario, the butane release could result in a vapor cloud fire. Modeling of this alternative release scenario using USEPA's RMP*Comp software indicates that off-site receptors could be impacted by such a vapor cloud fire. The potential off-site receptors include nearby businesses but do not include any residences. While we expect the hazard zone to be smaller than 0.1 miles, the USEPA's RMP*Comp software does not provide results less than the default value of 0.1 miles (528 feet) for a vapor cloud fire.
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 risk 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 Decatur 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 ins
truments, written operating procedures, employee and contractor training, regular equipment inspection and maintenance, and periodic program auditing to reduce the likelihood of butane releases 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 perio
dic 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 operation, 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 28 gas detectors located throughout the facility. The detectors are designed to warn an operator of a potential butane release and automatically shut down the process under certain conditions. 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 Decatur 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 Decatur 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 maint
enance to minimize the potential for unanticipated failure of our equipment. Our systems and programs are audited, typically by an outside company, at least once per year to evaluate their effectiveness.
We have recently reviewed and modified elements of our Prevention Program. We are presently reviewing the recommendations identified during Process Hazard Analysis of our equipment and procedures, performed by an independent expert with the participation of our facility personnel.