In the heart of Los Angeles, on a seemingly ordinary spring day in 1985, a sudden explosion tore through the Ross Dress for Less store at the corner of 3rd Street and Fairfax Avenue. This wasn’t an industrial accident nor was it an act of malice—it was a force of nature that had been lurking unseen beneath the city’s streets: methane gas.

The Fairfax District, a bustling area known for its shopping and historic Farmers Market, is also part of the larger Salt Lake Oil Field, a subterranean landscape rich in hydrocarbons. Over millions of years, decaying organic matter trapped in the earth’s crust had transformed into vast reservoirs of oil and methane gas. It was this methane that had stealthily migrated close to the surface, building up in closed spaces, waiting for an ignition source to set off a dramatic release.

On that day, as shoppers browsed through discounted apparel, an explosive mixture of methane, oxygen, and sewer gases found its spark. The blast shattered the storefront windows and caused a partial cave-in of the roof, turning the shop’s interior into a mangled wreck of metal debris. Twenty-three individuals were left with injuries severe enough to necessitate hospital care. In the aftermath, police cordoned off a four-block radius encompassing the bizarre spectacle of gas fires that jetted into the night sky, a haunting tableau that persisted until dawn.

The aftermath of the explosion was a scene of chaos and confusion. Emergency services sprang into action, addressing the immediate humanitarian concerns. But once the dust settled, a more profound issue loomed: the implications for the city’s ambitious underground Metro Rail project.

At the time, Los Angeles was in the throes of planning and constructing the Metro Red Line, a subway system that promised to link various parts of the sprawling city. Wilshire Boulevard, one of the busiest thoroughfares in Los Angeles, was to be a central artery in this new subterranean network. However, the explosion at Ross Dress for Less exposed the heretofore underestimated risk of tunneling through methane-rich zones.

Fears quickly escalated about the potential for similar explosions occurring elsewhere, particularly along the planned subway routes. The public, already wary of the high costs and disruptions associated with the Metro line, grew increasingly concerned about the dangers of tunneling through methane pockets.

In the wake of the explosion, city officials and Metro Rail engineers faced a daunting challenge. They needed to ensure public safety without derailing the critical infrastructure project. This task required a multifaceted approach. First, there was a thorough scientific investigation. Experts from various fields, including geologists, engineers, and safety specialists, were brought in to assess the risks of methane gas in the Fairfax District and along the proposed Metro route.

In a comprehensive regulatory response, the city imposed stringent building codes and established the Methane Zone Ordinance, which required new constructions in certain areas to implement gas detection and venting systems.

But the blast also resulted in a measure of technological innovation. The Metro Rail project incorporated state-of-the-art methane detection systems and emergency ventilation procedures in its design, setting a new standard for subway safety. The process was aided to some extent by significant community engagement. Public meetings and forums were held to address community concerns, offer reassurances, and provide education on the measures being taken to prevent future incidents.

Despite these efforts, the fear of what lay beneath Los Angeles’ streets had a chilling effect on the Metro’s progress. The Red Line faced delays as policymakers and the public grappled with the cost and complexity of making the subway safe. It wasn’t until the early 2000s, with the introduction of advanced tunneling technologies and robust safety protocols, that the Metro expansion regained momentum.

The 1985 methane explosion, while a localized event, reverberated through time to shape the development of Los Angeles in profound ways. It brought to the forefront the invisible risks of urban growth, challenged engineers and city planners to innovate, and ultimately reaffirmed the resilience of a city determined to rise above its subterranean challenges.

The dangers of methane beneath Los Angeles are far from gone. The Porter Ranch leak, also known as the Aliso Canyon gas leak, was a massive methane leak in the Santa Susana Mountains near the neighborhood of Porter Ranch in the northwest section of the San Fernando Valley.. Discovered on October 23, 2015, gas was discovered escaping from a well within the Aliso Canyon underground storage facility. On January 6, 2016, Governor Jerry Brown issued a state of emergency, and numerous media reports suggested that the methane could be dangerous to residents.  On February 11, the gas company reported that it had the leak under control, and finally  on February 18, state officials announced that the leak was permanently plugged. Still, an estimated 97,100 tonnes (95,600 long tons; 107,000 short tons) of methane and 7,300 tonnes (7,200 long tons; 8,000 short tons) of ethane were released into the atmosphere.

Today, as the Los Angeles Metro continues to expand, the lessons learned from that explosive day in 1985 continue to resonate, ensuring that safety remains at the core of the city’s march toward the future.