HERE’S WHY… Propane is stored as a liquid under pressure inside the cylinder. On a hot day, liquid expands and pressure increases. To guard against excessive pressure, every cylinder is equipped with a pressure relief valve which opens automatically to release gas and then closes when pressure is reduced.
If the cylinder is UPRIGHT, a small amount of vapor is released.
If the cylinder is HORIZONTAL, a large amount of liquid propane is released.
Liquid propane is highly volatile. It vaporizes instantly at a rate of about 270 to 1.) Put another way; if one cup of liquid propane is released, it instantly becomes 270 cups of pure propane vapor. Mixed with oxygen, it forms a combustible fuel which can readily be ignited by such ordinary sources as a cigarette or a spark from an electrical connection in your automobile. Unfortunately there have been many serious personal injury accidents over the years.
"While a number of fleets in New Jersey, including the Department of Transportation, have used biodiesel blends for many years, this pump opening marks the first time biodiesel will be sold directly to consumers in the state. We commend Woolley...Joe Jobe CEO (National Biodiesel Board)