The Ross Dress For Less Methane Explosion
On March 24th, 1985, an employee was just getting into work at his job in a local department store in Los Angeles, California. He was in a storeroom down in the basement under the “Ross Dress For Less” clothing store, with his punch card in his hand ready to check in for his shift. He slipped the card into the punch clock on the wall, but what would happen next would go on to shape law and legislation in Los Angeles to this day.
The spark from the punch clock stamping the time and date onto his punch card would cause an explosion that blew the roof off of the building. The shop windows shattered, the metal clothing racks curled and splintered, sending pieces of sharp shrapnel through the entire store and out onto the streets.
And for blocks around the building, and in the adjacent parking lot, cracks and fissures formed in the pavement, bursting into flames and terrifying the locals and the emergency crew that quickly showed up to help.
Miraculously, no one was killed, including the employee who was at the heart of the explosion, but twenty-three people ended up in hospital for their injuries.
But what happened and how did a punch clock cause so much devastation?
Well, it didn’t, not on its own anyway.
Los Angeles sits on top of the Salt Lake Oil Field which was discovered back in 1902 and since then, major industries have been set up to mine and extract the oil and other natural resources in and around the area. The Ross Dress For Less store was not necessarily near any active mines, but it was very close to old mine shafts and other underground tunnels that were slowly filling with the toxic gas, methane.
The thick layer of concrete that lines the city through all of the buildings and pavements and roads, created a layer that blocked all of that methane gas under the surface and, eventually, it had nowhere else to go. It broke through where it could and started accumulating in the basement of the department store until it reached explosive levels and one spark led it to doing what it did.
No one noticed the dangerous levels of methane in the basement because there were no sensors down there to actively check for it and natural methane is odourless. Companies actually add chemicals to the methane and natural gas that we use at home to try to make sure that we notice if there are any leaks in our systems and so we can, hopefully, get out before anything like that explosion happens or that we just inhale too much gas and die.
But there was no odour that day in March, 1985, and so the police and other emergency services evacuated four blocks around the area of the explosion, especially when the fire kept spreading and bursting through the cracks in the pavement, still burning and spouting flames long into the night.
Within days, a drill rig was brought in to test for any other gas accumulations under the surface and they found a large pocket of pressurised gas 42 feet below the parking lot of the Ross Dress for Less store, as well as similar but smaller pockets in and around the area. They quickly installed pressure gauges, control valves and a valved flare pipe was installed over that big pocket which would essentially allow people to release the gas in a controlled way that wouldn’t end up with another explosion.
But all of this created much bigger problems than just what to do with the gas that was building underneath the city. Dealing with natural gas build-ups was not a new thing for the city of Los Angeles, in fact, a school just across the street from the Ross Dress For Less store, had fans underneath it to help keep the air circulating underneath the building and make sure that dangerous levels of methane couldn’t build up.
But there were huge plans to build a subway underneath that particular stretch of the city. And it would make sense, the idea was to create a line that would allow people to travel from more of the suburban areas into the more industrialised areas of town, like the part of the city with shops like that department store, but there were already big petitions against it even before the explosion happened.
Now public representatives had something more to argue with for why there shouldn’t be any more digging going on under the surface of that stretch of the city and things got a little sticky.
A city task force was quickly put together to try to figure out where this big pocket of pressurised gas had come from and they came up with the theory that subsurface bacteria had been eating underground biomasses, including oil, and these bacteria had actually left that big pocket behind, but not everyone agreed. A lawsuit was filed against McFarland Energy who had drilled slanting mines from their property into oil reserves under the surface of land that was adjacent to theirs. The lawsuit claimed that the explosion had been a result of one of these mine shafts being incorrectly capped and sealed, but McFarland disagreed. They said that the methane gas had been created by natural causes and had nothing to do with their mining activities, but then they settled out of court and the lawsuit was dropped.
But it wasn’t this lawsuit that was the final nail in the coffin for the plan to create a subway in that area. Isotopic tests done on the gas revealed that it had, in fact, been produced by the Salt Lake City Oil Field and that meant that there could only be more.
The City of Los Angeles quickly declared approximately 400 blocks that were over the oil field as a “High Potential Methane Zone”, a term that hadn’t even existed before that explosion in 1985. They ordered the construction of several gas monitoring and venting wells throughout the city, that every building in that 400-block area should be equipped with methane detectors, and, of course, the plan to build a subway was scrapped.
This was a huge victory for the locals who had been petitioning against the project since it had been approved back in the 1980’s, but it wasn’t the end of the Salt Lake City Oil Field’s explosive behaviour.
Just four years later, so in 1989, another explosion happened because of a build-up of methane gas not too far from the Ross Dress For Less department store. To call it an explosion is probably a bit of an exaggeration on our part, but a build-up of methane gas, that was actually a result of the secure defences put up in the neighbouring area after the 1985 explosion, caused a big burst of mud, silt and methane gas to come streaming out of a bank. There was no explosion this time because there was nothing to ignite it and it was quickly determined that it was caused by one of the improper management of one of the relief wells, so luckily no one was hurt and it was a relatively easy fix.
It did lead to stricter regulations on methane monitoring, but due to advances in technology today, they’re not as closely monitored as they used to be. These advances in technology have also led to the construction of a subway that does now go through that once “no-go” area, so if any of you have ever been on the purple line in the Los Angeles, California, you’ve actually gone through a piece of land that helped shape the City of Los Angeles’ laws on methane and other natural gas regulations.