Explosion Fear as Gas Leak Shuts Down I-5 and Forces Castaic Indoors

A sudden gas line explosion in Castaic brought traffic to a halt and forced residents indoors on Saturday afternoon, after emergency crews responded to reports of a powerful blast and a strong smell of gas near homes and a local school.

The incident prompted the indefinite closure of Interstate 5 and raised urgent questions about what may have caused the rupture.

Explosion Reported Near Homes and School

Los Angeles County firefighters received multiple reports of a gas line explosion at around 4:20 p.m. near Ridge Route Road and Pine Crest Place, just south of Northlake Hills Elementary School.

Crews arriving at the scene quickly confirmed the presence of a strong gas odour, which could be detected from a considerable distance.

Fire officials said there were no injuries reported, but the location and intensity of the leak prompted a rapid escalation of safety measures as authorities worked to secure the area.

Emergency Crews Order Shelter in Place

As reported by The LA Times, the Los Angeles County Fire Department issued a shelter-in-place order at 5:40 p.m. covering much of Castaic. Residents were advised to close all doors, windows and vents, and to shut off HVAC systems as a precaution.

Firefighters were joined by a hazmat task force to assess the risk and monitor conditions. By 6 p.m., the gas company had shut off both sides of the damaged gas line, though emergency crews continued working to address a residual leak at the site.

5 Freeway Closure Causes Major Disruption

The blast had immediate consequences for regional travel. According to an official announcement on X, the California Highway Patrol closed all lanes of the 5 Freeway at 5:12 p.m., diverting northbound traffic to State Route 126 and southbound traffic to State Route 138.

'NB I-5: ALL LANES WILL BE CLOSED AND ALL TRAFFIC WILL BE DIVERTED TO SR-126. SB I-5: ALL LANES WILL BE CLOSED AND ALL TRAFFIC WILL BE DIVERTED TO SR-138. THESE CLOSURES WILL REMAIN IN EFFECT UNTIL FURTHER NOTICE DUE TO SAFETY HAZARD,' the post stated.

Traffic along the busy corridor remained at a near standstill for more than 90 minutes, compounding delays during a peak travel period. Motorists were urged to avoid the area as crews continued their response.

Attention Turns to the Cause of the Explosion

With the immediate danger stabilised, attention has shifted to what could have triggered the gas line explosion. Officials have not yet provided details on the specific cause, but determining how and why the rupture occurred will be central to the ongoing investigation.

Gas line failures can result from a range of factors, including infrastructure stress, environmental conditions or accidental damage, and authorities are expected to examine the surrounding terrain and pipeline integrity as part of their review.

Investigation Continues as Crews Remain on Scene

Fire officials confirmed that monitoring would continue until the area is deemed fully safe, with investigators working alongside the gas company to assess the damaged section of the line. Residents were advised to remain alert for official updates as conditions evolve.

The Castaic gas leak and explosion underscore the disruption that a single infrastructure failure can cause, shutting down a major freeway and forcing an entire community to take shelter while emergency teams work to prevent further risk.