TL;DR: On March 24, 1985, methane gas from a subsurface pocket beneath the former Salt Lake Oil Field forced its way into a Ross Dress for Less store in the Fairfax District of Los Angeles, causing an explosion. The incident directly triggered the formation of LADBS methane mitigation regulations and the modern methane barrier and vapor intrusion control industry that governs new construction in Los Angeles County today.
What Was the Ross Dress for Less Explosion?
The Ross Dress for Less explosion was a methane gas intrusion event that occurred on March 24, 1985, at a Ross Dress for Less store in the Fairfax District of Los Angeles, injuring dozens of bystanders and prompting an immediate citywide investigation into subsurface gas hazards. Firefighters, police officers, and HAZWOPER-suited personnel responded to the scene but were initially unable to identify the ignition source. Scientists and engineers were brought to the site after the cause remained inconclusive. Methane testing confirmed a high-pressure, high-concentration methane gas pocket existed beneath the surface of West Los Angeles. That gas plume had forced its way through foundation crevices into the building, where it accumulated until an ignition source triggered the explosion.
When Was Ross Dress for Less Founded?
Ross Dress for Less was founded in 1982, approximately three years before the 1985 Fairfax District explosion that would link the brand’s name permanently to Los Angeles methane hazard history. At the time of the explosion on March 24, 1985, the Fairfax District location was an active retail store open to employees and bargain shoppers on what appeared to be a routine Sunday. The incident had no connection to the company’s founding or retail operations but became a defining regulatory event for building safety in Los Angeles County.
What Did the Explosion Look Like?
The 1985 Ross Dress for Less explosion produced visible fire and structural damage at the Fairfax District storefront, with emergency responders and HAZWOPER teams scrambling across the scene while dozens of bystanders received medical attention on the surrounding streets. Archival photographs from the Los Angeles Public Library document the post-blast conditions at the site, showing the scale of the emergency response and the physical impact on the building. The images confirm the severity of the structural and emergency response footprint the methane intrusion event created. All referenced photos originate from the Los Angeles Public Library collection:
https://tessa.lapl.org/cdm/singleitem/collection/photos/id/30110/rec/3
https://tessa.lapl.org/cdm/singleitem/collection/photos/id/30114/rec/34
https://tessa.lapl.org/cdm/singleitem/collection/photos/id/30116/rec/35
What Caused the Methane Gas Intrusion at the Fairfax District Site?
The methane gas intrusion was caused by a high-pressure subsurface gas pocket originating from the legacy oil field geology beneath West Los Angeles, which forced methane upward through cracked foundations and into the enclosed retail structure. The combination of three specific conditions produced the explosion: high-concentration methane gas intrusion, an enclosed structure with limited ventilation, and an ignition source. Post-explosion methane soil gas tests confirmed the vapor source was still actively expelling methane after the initial event. City engineers responded by installing relief points throughout the area to allow controlled burns of subsurface methane at ground level, which stabilized the immediate hazard.
How Did the Salt Lake Oil Field Create the Methane Hazard?
The Salt Lake Oil Field, discovered in 1902 and once one of the fastest-growing oil fields in the Los Angeles area, left behind a subsurface environment saturated with residual hydrocarbon energy after its wells were abandoned, creating the methane accumulation conditions that contributed to the 1985 explosion. At its peak, the Salt Lake Oil Field operated over 300 active wells and produced more than 50 million barrels of oil. As those fields were depleted, oil operators relocated and left behind abandoned wells and gas-rich subsurface formations beneath what became a high-demand residential and commercial real estate corridor. Developers built retail and residential structures over this geology without knowledge of the pressurized subsurface methane that remained.
| Condition | Peak Operations (Early 1900s) | Post-Abandonment (Pre-1985) |
|---|---|---|
| Active Wells | Over 300 | Abandoned |
| Oil Production | Over 50 million barrels | Depleted |
| Land Use | Oil extraction operations | High-end retail and residential development |
| Subsurface Gas Pressure | Managed via active extraction | Uncontrolled high-pressure methane pockets |
| Regulatory Framework | Oil production standards | No methane intrusion building standards existed |
How Did the Explosion Create the Methane Mitigation Industry?
Within days of the March 24, 1985 explosion, the Los Angeles Department of Building and Safety (LADBS) assembled a task force of methane gas engineers, scientists, soil engineers, vapor intrusion experts, and methane consultants to develop a regulatory and construction framework that would prevent recurrence. That task force produced what became the modern methane mitigation industry for Los Angeles. The resulting solution incorporated multiple engineering disciplines and built-in redundancy to limit and control any future methane gas intrusion. The primary protective mechanism to emerge from this process was the methane barrier, a physical membrane installed beneath building foundations. Learn more about the methane mitigation process as it is applied to construction projects today.
How Were Methane Barriers and Vapor Membranes Developed?
Methane barriers were developed by adapting proven spray-applied asphalt emulsion waterproofing membranes from the existing waterproofing industry after LADBS-licensed testing agencies confirmed those materials had a measurably low mass diffusion rate for methane gas. Because LADBS could not allocate the time required to develop entirely new construction materials, gas vapor intrusion consultants evaluated existing products with decades of documented field performance. Methane test results identified specific spray-applied asphalt emulsion membranes as effective barriers. LADBS consultants then developed the first formal specifications for methane barriers based on those materials. To establish redundant protection layers, methane gas hazard engineers incorporated methane detectors, methane alarms, and lowest-level ventilation fans into the system design for high-risk intrusion zones. These elements were codified into the LADBS Methane Mitigation Standard Plans that define current construction requirements.
What Are LADBS Methane Mitigation Standard Plans?
LADBS Methane Mitigation Standard Plans are the regulatory framework governing methane intrusion protection requirements for all new construction projects within the City of Los Angeles, developed directly in response to the 1985 Ross Dress for Less explosion. Forty years after that event, LADBS continues to oversee the implementation of methane mitigation systems on new construction projects throughout Los Angeles, Glendale, the NoHo Arts District, Downtown Los Angeles, and the broader Los Angeles County jurisdiction. Neighboring regulatory bodies have since developed their own parallel standards, including the LA County Environmental Programs Division, the Orange County Fire Authority, and the City of Long Beach. At the state level, the California Department of Toxic Substance Control developed the Site Mitigation and Restoration Program to address vapor intrusion from all categories of subsurface gas hazards, expanding the regulatory reach of what began as a single post-explosion task force in 1985.
Quick Recap
- The Ross Dress for Less explosion occurred on March 24, 1985, in the Fairfax District of Los Angeles.
- Methane gas from a high-pressure subsurface pocket beneath the former Salt Lake Oil Field forced its way into the building and ignited.
- The Salt Lake Oil Field produced over 50 million barrels of oil from more than 300 wells before abandonment, leaving pressurized residual gas formations beneath developed land.
- Post-explosion methane soil gas testing confirmed the subsurface source was still actively expelling methane after the initial event.
- LADBS assembled a multi-discipline task force within days of the explosion to develop a prevention framework.
- Spray-applied asphalt emulsion waterproofing membranes were adapted and tested as the first methane barriers due to their low methane mass diffusion rates and existing field data.
- The resulting LADBS Methane Mitigation Standard Plans established layered requirements: methane barriers, gas detectors, alarms, and ventilation systems.
- Regulatory frameworks based on the LADBS model have since been adopted by LA County, Orange County, Long Beach, and California DTSC.
Frequently Asked Questions
What year did the Ross Dress for Less explosion happen?
The Ross Dress for Less explosion happened on March 24, 1985, at the company’s Fairfax District location in Los Angeles.
What caused the 1985 Fairfax District explosion?
A high-pressure, high-concentration methane gas pocket located beneath the surface of West Los Angeles forced gas upward through cracks in the building’s foundation. The methane accumulated inside the enclosed structure until it reached an ignition source, causing the explosion.
Is the Fairfax District in a methane zone?
Yes. The Fairfax District sits over legacy oil field geology from the former Salt Lake Oil Field, which is a source of subsurface methane. Properties in this area are subject to LADBS methane zone designation and mitigation requirements for new construction and renovation.
What is a methane barrier and why is it required?
A methane barrier is a spray-applied or sheet-applied membrane installed beneath a building’s foundation slab to prevent subsurface methane gas from migrating into occupied structures. LADBS requires methane barriers on new construction projects located within designated methane zones, a standard that originated directly from post-1985 engineering work following the Ross Dress for Less explosion.
Which Los Angeles agencies regulate methane mitigation?
The Los Angeles Department of Building and Safety (LADBS) is the primary enforcement authority for methane mitigation in the City of Los Angeles. LA County Environmental Programs Division covers unincorporated county areas. The California Department of Toxic Substance Control (DTSC) governs vapor intrusion at contaminated sites statewide under its Site Mitigation and Restoration Program.
Does methane mitigation apply to renovation projects, not just new construction?
Methane mitigation requirements can apply to renovation projects depending on the scope of work, the permit type, and whether the property is located within a designated methane zone. Property owners and contractors should verify current LADBS requirements before submitting permit applications for projects in Los Angeles, Glendale, the NoHo Arts District, Downtown Los Angeles, or other areas within Los Angeles County.
How do I know if my property is in an LADBS methane zone?
LADBS maintains methane zone maps that classify properties by hazard level. A methane soil gas survey and site assessment can confirm subsurface conditions and determine which LADBS Standard Plan requirements apply to your specific project address.
Working on a project in a methane zone or contaminated soil site in Los Angeles, Glendale, the NoHo Arts District, Downtown Los Angeles, or Los Angeles County? LEARN MORE