The State of California recently introduced an amendment to Title 8 summarized below:

TITLE 8: Division 1, Chapter 4, Subchapter 14

Petroleum Safety Orders – Drilling and Production

Article 2. Definitions

§6505. Definitions.

The following definitions shall apply in the application of these Orders.

Although diesel engines use electronics, the ignition system operates through compression to ignite the fuel. Consequently, simply turning off the key does not necessarily kill the engine. If a diesel engine has an uncontrolled external fuel source, it could accelerate to very high RPM and potentially explode. This condition is called diesel engine “overspeed” or is termed a “runaway” diesel engine. The most common occurrences of overspeed or runaway are environments where invisible external hydrocarbons are present in the atmosphere and are sucked into the intake manifolds of operating diesel engines.

The BP Texas City Refinery explosion in 2005 killed 15 people and injured over 180. The explosion was caused by an idling diesel pickup that ingested flammable gases thus leading to “overspeed”, which then ignited the gas cloud and subsequently the entire plant.