Executive Briefing on Fire and Explosion at Atlas Castings and Technology

Executive Briefing

Executive Briefing on Fire and Explosion at Atlas Castings and Technology

Richard Hildreth

EDMG 240 – Chemistry of Hazardous Materials

December 29, 2013

Note: This paper is written from the prospective of an executive briefing presented to the Tacoma City Council on this event. The purpose is to provide the Council with background of this event and demonstrate the critical need of adequate resources to protect the citizens of Tacoma from similar type events.

Executive Briefing on Fire and Explosion at Atlas Castings and Technology

Part I – The Fire, Explosion and Aftermath:

When handling any Hazardous Material, situational awareness and proper staffing, training and equipment are critical for safety.  Even the slightest mistake could result in any incident becoming a catastrophic event. A prime example of this is the October 2007 fire and explosion of a propane truck at the Atlas Castings and Technology (formerly Atlas Foundry) in Tacoma, Washington. At approximately 3:00 PM. while transferring liquid propane from a tanker truck to stationary tanks a sudden blowout of propane vapors made its way inside the foundry and was ignited.  The initial flash type explosion seriously injured the driver; however he was able to stumble almost 200’ to a perimeter fence and was taken to a hospital. Unfortunately, as a result of serious internal injuries, he died four days later. The subsequent explosion, which is known as a Boiling Liquid Expanding Vapor Explosion or BLEVE created a fireball that went over 1000 feet into the air and tossed one of the axles of the tanker truck, still on fire onto the elevated  State Route 16 (highway) overpass (Duryee & Romano, 2007). This overpass is almost 150 feet in elevation above the valley floor and almost 1000 feet away from the explosion. During this event, power was knocked out for over 13,000 customers when debris destroyed a Tacoma City Light Substation and the shell of the truck’s propane tank itself landed on power lines over 500 feet away (Vane, Eskenazi, & Perry, 2007).  The explosion was felt more than 20 miles away. Fear of additional BLEVEs of one or both of the two 30,000 gallon stationary tanks demanded firefighters take a defensive approach to the incident and is evidence why situational awareness at these types of events is always critical.

What makes this incident a great case study is the amount of video that is available of the incident prior to, during and following the incident and explosion. A security camera located just north of the incident shows the truck and driver, a sudden burst of Propane Vapors and 34 seconds later the initial explosion (KOMO News, Oct 15, 2007).  Although the security camera was damaged before the subsequent explosions, Washington State Department of Transportation (WSDOT) cameras and private video taken by witnesses show the explosive power of this event (KOMO News, Oct. 6, 2007). A link to one of these videos, now used in case studies along with specific details is provided later in this report.  The video shows both the fire and the BLEVE from a vantage point approximately 2000 feet away, on Sprague Avenue near the intersection with Highway 18.

This event began with the delivery of propane by Chuck McDonald, a 64 year old driver employed by IXL Transport Services of Molalla, Ore. McDonald was in the process of transferring 11,000 gallons of liquid propane to two 30,000 gallon stationary bulk storage tanks (McClary, 2008).  Both stationary tanks were connected together by liquid and vapor transfer lines designed to allow transfer between tanks and/or simultaneous filling. As per regulations, each storage tank had pressure relief devices located on the top of each tank (Lewis, 2011). As it will be shown later, these pressure relief valves played an important role in the response and recovery of this incident.  Upon the tanker truck’s arrival at the facility, it was discovered that fittings on the liquid delivery line had separated from the hose and would require repair prior to offloading of product.  These repairs were attempted by the driver and three Atlas Foundry workers, none of whom had specific training for repairs of high pressure lines. Repairs were made using items found on site including several hose clamps and pins not rated for use on high pressure equipment. These repairs failed following activation of the Power Take Off (PTO) unit used to pressurize the transfer from the truck to the tank assembly. The security camera video clearly showed the driver, Chuck McDonald, hooking up this repaired hose to the truck, activating the PTO and walking towards the stationary tanks to open the Globe valves on the tank intake manifold. The truck was soon rapidly surrounded with a cloud of highly volatile propane vapors.  These vapors found their way into the foundry and 34 seconds later were ignited by an electric arc furnace inside the foundry causing the initial fire and flash type explosion. 

Adding to the series of events that led to this event was the failure of an internal liquid shutoff valve on the tanker truck. This valve located inside the transportation cargo tank was designed to monitor actual flow rate against a preset safe flow rate.  As designed in the event of a rupture or pipe break, the valve should have closed without human interaction within 20 seconds. An additional safety device, a thermally activated valve rated at 250 F also should have closed, shutting off the fuel supply from the fire. These failures allowed fuel to feed the fire resulting in a BLEVE approximately seven minutes later. 

A You Tube video published on the My Fire Fighter Nation website shows the initial fire with flames shooting hundreds of feet in the air. A link to this video can be found at http://my.firefighternation.com/video/889755:Video:115488 .

At approximately the 30 second mark of the video, emergency vehicle sirens can be heard responding (This would be approximately 3 minutes after the initial explosion) and even from this location, an estimated 2000 feet northwest of the event, the roar of the fire itself can be heard. It should be noted that at the 1:27 mark in the video Emergency Response Vehicles can be seen in the background establishing a perimeter (this engine would be blocking traffic on South Tacoma Way south east of the fire). At the 2:08 mark small explosions believed to be the tires on the truck can be heard exploding. At the 4:15 mark the BLEVE occurs creating a fireball that some people estimate was over 1000 feet in the air. It was this explosion that tossed one of the truck axles onto the elevated freeway overpass (Hwy 16). That overpass would be immediately to the right of the view shown in the video. Other debris landed on Interstate 5 seen in the background.

The regional impacts of this event were enormous. The Washington State Patrol immediately closed both Interstate 5 and SR 16 causing massive backups that impacted traffic for hours. The Federal Aviation Administration banned aircraft within five miles requiring a reroute of aircraft taking off from SeaTac Airport. As previously stated, debris from this explosion destroyed a Tacoma City Light substation located 500 feet away knocking power out to over 13,000 customers until the area could be isolated and power restored.

In response of the BLEVE, Tacoma Fire Department dispatched 20 trucks and 50 firefighters to the scene.  Additionally, Tacoma Police were dispatched to secure a perimeter of approximately ¼ mile. As a result of firsthand information from the evacuating workers and the fact the two stationary tanks could still erupt, the Incident Commander pulled firefighters back to a defensive position. He ordered Tacoma Police to expand the exclusion zone and evacuate the neighborhood including homes near where the previous video was taken.

Because of plant layout, visual assessment of the scene was difficult; however, by rotating an elevated closed circuit camera operated by WSDOT located on the Highway 16 overpass the command staff were able to gain visual observation of the stationary tanks and scene.  They could visually see flames erupting from the pressure relief valves located atop each tank and what appeared to be an active fire beneath the tanks fueled by a ruptured natural gas line.  As Puget Sound Energy worked to shut off flow to the ruptured line, firefighters positioned three trucks with remote controlled water cannons within 150 feet of the fire and directed streams of water to cool the tanks to avoid additional BLEVE’s.  Care was taken to use indirect water spray to allow the fire from the relief valves to continue to burn as this was safely allowing pressure to reduce while burning off the vapor. An additional reason to use indirect water spray is that icing could occur around the valves and safety devices, causing additional hazards or failures. To keep tanks of this size cool a minimum of 512 gallons per minute are needed based on the formula 5 x Sq. Root of the Capacity in US Gallons (Emergency Response Guide, 2012, p. 367).  By the conclusion of this operation over 4 million gallons of water were needed to cool these stationary tanks.

After Puget Sound Energy was able to cap off the ruptured natural gas line, firefighters extinguished the ground fire but allowed the venting propane tanks to continue to burn off vapor. The tanks were then flooded with inert gas and removed for disposal. Firefighters remained on scene for 24 hours to ensure all hotspots were extinguished.  Washington State Department of Transportation inspectors examined the freeway overpass for any potential damage and Highway 16 was reopened at approximately 2 AM, about 11 hours after the initial explosion. On Sunday morning investigators from the Tacoma Fire Department, Washington State Labor and Industries and the Washington State Patrol then went to work to assess the series of events that contributed to this event. Part II of this report will cover the results of their investigations.

Part II: The Investigation

In investigating the series of events that resulted in the fire and explosions at the Atlas Castings and Technology (formerly Atlas Foundry) Tacoma Fire, Labor and Industries and independent investigators looked over evidence including security camera documentation, fittings and the remnants of the tanker truck.  Based on these investigations, it can be safely assumed the series of events being reported resulted in the BLEVE and the death of the tanker truck driver, Charles McDonald.  As this case may still result in both official and civil litigation, nothing in this report is provided with the intent of assigning blame, but rather to provide an executive overview of known facts.

The transportation and handling of all hazardous material, including propane is regulated by the US Department of Transportation and in Washington State is enforced by the Washington State Patrol. All drivers are subject to rigorous training and certification which is required to be updated every three years. All evidence points to the certifications for the driver Charles McDonald being current and valid at the time of this event. Additionally, there were no reports of recent citations of the driver or the vehicle involved.

It should be pointed out that propane gas is approximately 1.5 times denser than air. As a result, propane vapor clouds will stay relatively close to the ground and sink into open ditches, sewers and other low spots. It is considered highly flammable with a flashpoint of 155 F and a burning temperature of over 940 F.  At an ambient temperature of 60 degree Fahrenheit, liquid propane has a density of approximately 4.2 pounds per gallon. As Propane’s boiling point is just over 43 degrees Fahrenheit at atmospheric pressure, and this boiling point increases as pressure rises, liquid propane must be stored in pressurized containers or tanks to maintain liquid form.  When a pressurized propane tank is exposed to fire such as was seen in this incident, the liquid propane is heated above its boiling point causing the propane to convert from liquid to gaseous form causing an increase in pressure. Additionally, as propane is heated, the liquid expands at a rate of 1.5% per 10 F of temperature rise. This conversion as well as the expansion of liquid rapidly causes the pressure inside the tank to rise. Typically when this occurs, pressure relief devices allow for the controlled release of excess pressure. However when this pressure exceeds the critical limits of the tank, a catastrophic rupture could occur; this rupture results in two things, the sudden explosive release of the gas and the almost instantaneous vaporization of the remaining liquid to gaseous form (Bachman, 2005). Although BLEVE’s are not limited to failures of containers containing flammable materials, in cases such as these when they do, the sudden release of flammable gas often results in a fireball like the one seen on October 7^th. Additional hazards from LPG type BLEVEs include thermal radiation, projectiles from the explosion and secondary fires caused by burning material (Emergency Response Guide, 2012, p. 364).

In transferring liquid propane from a tanker truck to a fixed or stationary storage tank the transfer is accomplished with the use of two separate pressure rated hoses, the first for delivery of the liquid propane and the second to allow vapors to return to the truck.  Each hose should be rated at a minimum of 1700 PSI with fittings designed for both the pressure and to resist any corrosive or erosive impacts of movement of pressurized material.  Additionally, multiple safety features including automatic shut off valves are used in hopes of preventing the type of event discussed in this report.

When the field repaired hose connection on the transfer line failed, it enveloped the truck in a white cloud of propane gas. This cloud stayed relatively close to the ground and followed a drainage gutter approximately 75 feet and made its way inside the building. It is believed this cloud was ignited by an Electric Arc furnace located inside resulting in the initial explosion. There were two minor explosions followed by the BLEVE approximately 7 minutes into the event.  It was as a result of this BLEVE that most of the physical damage occurred including launching pieces of the tanker truck hundreds of feet into the air and as far away as one half mile from the explosion.

Kevin Lewis of Case Forensics who also investigated the cause of the BLEVE noted in his report that the recovered globe valves on the stationary tanks were in the closed position which prevented propane from these tanks to add more fuel to the fire.  The position of the thermally activated valve on the truck was also in the closed position; however based on the video footage and other indications it appears the BLEVE triggered the closure of the valve post incident. In the CASE report it was noted that there were several design flaws in the valve in question. These flaws included the nylon plunger that was triggered by the fusible link, lacked sufficient force to push the release lever while under pressure.  The CASE report concluded” an appropriate safety factor was not incorporated in the selection of an emergency safety device on an internal valve. A redesign of the valve further decreased the likelihood that the safety device could function to prevent a catastrophic event, such as a BLEVE from occurring.”

The Washington State Labor and Industries has issued a citation to Atlas Castings and Technology citing three serious violations of workplace safety and health regulations (Labor and Industries, 2008).  A fourth violation, not having a remote shutoff valve on the stationary tanks was not considered to be a factor in this incident nor did it contribute to the explosion. The four violations are listed below.

·         Not properly training employees on the repair and maintenance of pressurized LP-gas systems.

·         Using hose connections that were not rated for LP-gas service and would not withstand the pressure.

·         Not testing the repaired hose after assembly to ensure it was free from leaks under normal use.

·         Not having a shutoff valve with means of remote control to protect against uncontrolled discharge of LP gas from piping close to the point where the piping and hose connected.

Atlas Castings & Technology is appealing the citations making the following comments on each citation:

·         The first concludes that Atlas failed to train two employees on the repair and maintenance of the propane system. The foundry contends these were not the employees’ duties, and that they would not have tried to fix the system had they not been urged and directed to do so by McDonald.

·         A second citation faults Atlas for using hose couplings that would not withstand the minimum pressure required. Atlas says the agency did not conduct performance testing to validate this opinion, and the use of the couplings was the responsibility of the driver.

·         A third citation blames the foundry for not testing the hose after the attempted repairs, but Atlas states that its employees did not place the hose into use before the tests could occur, because that was McDonald’s responsibility.

·         The final citation finds Atlas responsible for not providing a backflow-prevention device closer to the site where the delivery hose was connected. However, the foundry stated, the evidence “shows that the system did have a backflow device in place. The backflow device was installed along with the original system in the early 1950s, at which time it was in full compliance with the then current codes and no upgrades have since been required.”

It is the foundry’s position that the driver was in violation of both Federal and State regulations when he failed to red tag the delivery hose and immediately take it out of service. It should be pointed out that the Department of Labor and Industries investigation was limited to Atlas Castings itself and that the Department does not have jurisdiction over the truck or the driver.

In conclusion I wish to emphasize the fact that events such as this are resource dependent and impossible to prepare for.  As was shown this type of event can occur as a result of seemingly minor mistakes but can have tragic or in this case explosive results. This is why it is so critical to maintain operational readiness in the Tacoma Fire Department.  We understand why cuts in staffing have been considered and we agree that in these times of reduced revenues that each of us needs to tighten the belt. What we cannot afford is to reduce our ability to respond to unexpected events such as was seen October 7, 2007.  Continuous training, up-to-date equipment and most of all the manpower needed to respond for multiple operational periods is critical to the safety and security of our community.

We recognize how difficult your job is, to craft an austere budget without creating more risk.  We wanted to bring to your attention some intangible facts that should be considered in your deliberations. It is our hope that this executive briefing will illustrate how critical our resources are. As stated at the beginning, when handling any Hazardous Material, situational awareness and proper staffing, training and equipment are critical for safety. We must maintain our capability to safely respond to any event that threatens the safety and wellbeing of our citizens.

Works Cited

Atlas Foundry Explosion from WSDOT Cam at SR16 & Union Ave. (2007, October 10).
Retrieved from http://www.youtube.com/watch?v=nAddMqVzrO0
Note this video was used as part of a broadcast on KOMO news 4 in
Seattle Washington.

Atlas Foundry Explosion - Tacoma, WA. (2007, October 8). Retrieved from Fire
Fighter Nation website: http://my.firefighternation.com/video/
889755:Video:115488

Atlas Will Appeal Citations Following Deadly Explosion. (2008, April 6).
Foundry Management and Technology. Retrieved from http://foundrymag.com/
testingqc/atlas-will-appeal-citations-following-deadly-explosion

Bachman, E. G. (2005, March 1). Propane Explosion: A Case Study. Retrieved from
Fire Engineering website: http://www.fireengineering.com/articles/print/
volume-158/issue-3/features/propane-explosion-a-case-study.html

Duryee, T., & Romano, B. J. (2007, October 7). Foundry blast jars Tacoma.
Seattle Times. Retrieved from http://seattletimes.com/html/localnews/
2003930997_explode07m0.html

Emergency Response Guide (USDOT PHMSA, Comp.). (2012). Retrieved from
http://phmsa.dot.gov/staticfiles/PHMSA/DownloadableFiles/Files/Hazmat/
ERG2012.pdf

KOMO News. (2007, October 6). Huge explosion at Tacoma foundry felt for miles
around [Video file]. Retrieved from http://www.komonews.com/news/local/
10288352.html?tab=video&c=y

KOMO News. (2007, October 15). New video shows events that led to foundry
explosion [Video file]. Retrieved from http://www.komonews.com/news/
local/10560846.html?tab=video&c=y

Labor and Industries, Atlas Foundry cited for October explosion, (Wash. 2008).
Retrieved from http://www.lni.wa.gov/news/2008/pr080404a.asp

Lewis, K. H. (2011). Safety device failure results in tanker BLEVE at Atlas
Foundries. Retrieved from CASE Forensics website:
http://www.case4n6.com/page.php?getpage=CASEofthequarter

McClary, D. C. (2008, April 29). Explosion and fire at Atlas Castings and
Technology in Tacoma kills truck driver and injures three workers on
October 6, 2007. Retrieved from HistoryLink.org website:
http://www.historylink.org/index.cfm?DisplayPage=output.cfm&file_id=8612

Peterson, D. F. (2002, April 1). BLEVE: Facts, Risk Factors, and Fallacies.
Retrieved from FireEngineering.com website: http://www.fireengineering.com/ articles/print/volume-155/issue-4/features/ bleve-facts-risk-factors-and-fallacies.html

Vane, L., Eskenazi, S., & Perry, N. (2007, October 8). The Tacoma blast "It's
amazing there were not more" hurt. Seattle Times. Retrieved from
http://seattletimes.com/html/localnews/2003932895_explode08m.html