On a cold winter day, a 49 year old construction site foreman arrived early for work. As he had done on many prior occasions, the man unlocked the company storage container and set about lighting the propanefueled heater used to heat the container which, in addition to storing tools, served as shelter for the employees. The man turned on the gas and clicked the igniter. A large explosion occurred on the fifth click: the man was thrown against the side of the container and sustained second and third degree burns to 7-8% of his body.

The Fire Chief, who heard and felt the explosion from his home one mile from the accident site, immediately traveled to the scene to investigate. A leak was detected from a valve on the propane cylinder. Ultimately, the Fire Marshall concluded the explosion occurred as a result of the leaking valve.

Brandon Swartz of the Swartz Culleton law firm filed suit on behalf of the injured worker against the gas cylinder manufacturer and several component makers, alleging that gas leaking from the valve had accumulated in the storage container, creating the conditions for an explosion. However, during testing, flow meter measurements of gas leaking from the valve called into question the role played by the valve in the explosion. The defendants’ experts placed the gas cylinder inside a sealed chamber and measured the propane leak with an electrical flow meter. The results showed that the amount of propane leaking from the cylinder was too small to have filled the work container with a propane concentration of 2.1%, which is the minimum concentration required for combustion. The defendants argued that the Fire Marshall had rushed to judgment and had overlooked other possible causes for the explosion, such as acetylene welding equipment that was also stored in the container.

Faced with the defense’s compelling calculations, Brandon Swartz and his expert went back to the drawing board. While the defense’s rationale made sense, Swartz was convinced of a flaw in their theory because the possibility that the valve leak was a mere coincidence was just too unlikely. He recalled that prior to the flow meter test, soapy water had been placed on the valve to locate the leak. The escaping gas created a ½ to ¾ inch bubble every second. Using that fact, he calculated that the propane was leaking at a rate of .3 cubic feet per hour, a much higher rate than had been measured using the flow meter. Additionally, because the accident had occurred following a three day holiday weekend, the gas had been leaking into the container for three days before the accident, and not two days as assumed by the defense. Using this new data, the plaintiff’s expert calculated that at the time of the explosion, the concentration of propane from the valve leak was 2.1%, enough to create the blast. Soon after receiving the plaintiff’s report, the gas cylinder manufacturer and other defendants agreed to settle.