For half a century, California has been at the forefront of reducing emissions and cleaning up air pollution.
And the state has made breathtaking progress since the days of early-Seventies technicolor photochemical smog alerts.
But then bad things happen--and a leak at a single natural-gas well shows how much damage can be done to air quality by hydrocarbon extraction.
According to Reuters, in an article published two weeks ago, an uncontrolled leak at the Aliso Canyon storage field is emitting 50,000 kilograms (110,000 pounds) of methane into California's air every hour.
That represents fully one-quarter of the state's entire methane emissions from all sources.
That leak may not be plugged until sometime in March or April, according to Southern California Gas CEO Dennis Arriola. That could be as long as six months after fumes were first detected on October 23.
UPDATE: This article was first published on December 15, 2015. On January 6, California governor Jerry Brown declared a state of emergency, evacuating the Porter Ranch area of its 30,000 residents. They join the 2,000 households nearest to the huge leak that had previously been relocated.
Meanwhile, the state's Environmental Defense Fund has a live-updating methane emissions count that displays the value of the gas lost.
1970s Los Angeles smog depicted in the Honda short film
The methane emissions have sickened nearby residents in the nearby suburb of Porter Ranch. About 200 households have been relocated away from the leak; 500 more families await their moves in turn.
The 3,600-acre storage field at Aliso Canyon is the second-largest such facility in the western U.S., after one in Montana, according to Reuters. Natural gas is pumped in the field's wells during the summer and extracted in the winter, when energy demand is higher.
The leak, thought to be caused by a broken pipe in an injection well, has foiled several previous attempts to halt it.
California has aggressively encouraged its electric utilities to use natural gas for power generation, along with renewable sources, giving the state's electric grid a relatively low carbon footprint per kilowatt-hour of electricity.
But that natural gas has to be stored somewhere, in this case within a mile of suburban subdivisions.
And because methane is a far more damaging greenhouse gas than carbon dioxide, the field's total emissions as of December 1 equaled the effects of 800,000 tons of CO2, according to CARB--or the equivalent of the yearly greenhouse-gas emissions of 160,000 vehicles.
Natural gas flaring from oil well [licensed under Creative Commons from Flickr user Sirdle]
A source in the oil and gas business who prefers to remain anonymous told Green Car Reports, "This sort of storage field is somewhat rare, and it’s good that they caught it when they did--otherwise they might have been short of gas in the coming winter."
The source noted that in less well-regulated regions of the world, the bigger greenhouse-gas issue is flaring, or burning natural gas that is released as a byproduct of oil extraction.
Natural gas is often viewed as "worthless" in some oil-extracting regions--especially where there's not enough volume to justify the huge expense of constructing a liquid natural gas facility to compress it, load it into tankers, and ship it to other regions where a market exists.
Southern California Gas is owned by Sempra Energy, based in San Diego.
[hat tip: Brian Henderson]