Flames Climb Bhumibol Bridge 2 Pier, Unveiling Plastic Pipe Dangers

A column of flame climbing the pier of Bhumibol Bridge 2 forced evening commuters to pull over and stare, phones filming what looked at first like a disaster in the making. Within 90 minutes the blaze was out, traffic was moving, and engineers were already declaring the megastructure unharmed—but the incident has reignited debate about plastic infrastructure and urban fire safety.

Fast Facts At A Glance

• 50-metre flame column raced up a black PE drainage pipe on the upstream pier.

• More than 10 fire engines, including a high-reach platform, were dispatched.

• Firefighters needed extra water pressure to reach the underside of the deck.

• Bridge pillars and cables passed a preliminary structural check; only the pipe was lost.

• Investigators say four boys with firecrackers likely touched off the blaze; vendors who supplied the fireworks are now in custody.

A Routine Commute, An Unexpected Inferno

Witnesses driving the industrial ring road between Phra Pradaeng and Bang Pakok describe an abrupt shower of sparks, followed by an orange streak that climbed the pier like a fuse. The drainage conduit—made of high-density polyethylene—acted as a vertical wick, carrying flames from the litter-strewn base all the way to the deck. Thick black smoke rolled east across the Chao Phraya, briefly reducing visibility for motorists.

“Cars stopped. People got out. Everyone thought the bridge was going to collapse,” said Somchai Chuerchai, a delivery-van driver who filmed the first five minutes.

Was The Bridge Ever In Real Danger?

Engineers from the Department of Rural Highways performed a night-time tap test, then returned at dawn with ultrasonic scanners. Their verdict: concrete cover chipped only 1 cm at the base, well inside design allowances; cables, bearings and box-girder steel never heated to critical temperature. In short, the 192-billion-baht structure remains safe for daily loads of >100,000 vehicles.

Plastic Pipes: Cheap, Light, And Flammable

The fire has drawn fresh scrutiny to polyethylene and polypropylene components that pepper Thailand’s bridges. Civil-engineering lecturer Dr. Ratchapon Intharawong notes that while PE resists corrosion, vibration and salt spray, it has a low ignition point and drips molten fuel once alight. That combination, he argues, “should push designers toward shielding or metal alternatives in high-risk zones where litter accumulates."

Among Bangkok’s elevated highways, roughly 70 km of plastic drainage has been installed since 2016, according to an internal Expressway Authority inventory.

Firecrackers, Childhood And Criminal Liability

Police from Samut Prakan’s juvenile division have questioned four boys, all 11 years old, who admitted lighting cap guns and tiny ‘ping-pong bombs’ under the pier. Officers traced the fireworks to an informal stall hidden behind a tuk-com spare-parts shop. Under Thailand’s Child Protection Act, the boys face rehabilitation, not prison, but the adult vendor could be charged with selling explosive devices to minors—a crime that carries up to 3 years in jail.

Logistics Impact: Minor, But The Lesson Is Major

Because the flames never reached the carriageway, the agency kept all four lanes open in both directions after midnight. Still, freight companies that lean on the Outer Ring Road as a gateway to Laem Chabang lost an estimated ฿12 M in delivery delays. Insurers are already lobbying for mandatory CCTV coverage under bridges to cut response times and fraud.

Déjà Vu: Thailand’s Short List Of Bridge Fires

Rama IX Bridge car blaze (2024): a stalled Benz caught fire, snarling traffic but sparing the structure.

Rama II viaduct collapse (2025): not a fire, but a reminder of how quickly trust evaporates when concrete fails.

Phra Pok Klao transformer fire (2020): electrical flashover charred cables but left the old bascule spans intact.

Urban planners say these incidents underscore a single point: secondary elements—pipes, wiring, signage—often ignite first, creating panic long before the main frame is threatened.

What Happens Next

• Deep-scan structural audit scheduled for later this week, including infrared thermography to detect latent heat pockets.

• Replacement drainage will shift to fire-retardant PVC-C pending budget approval.

• The Ministry of Interior is drafting an order that forbids open storage of combustible waste within 20 m of any bridge pier nationwide.

• School holiday programmes in Samut Prakan will add a module on safe festival fireworks after local educators requested resources.

For Bangkok’s drivers, the takeaway is simple yet unsettling: the next traffic-stopping blaze may start with a spark no bigger than a match. Keeping Thailand’s bridges safe is no longer just an engineering exercise—it’s a community responsibility.