The exercise, jointly organised by the Ministry of Public Security and the HCM City People's Committee, took place in Long Son Commune, involving 2,571 personnel, 147 vehicles and six service animals.
Senior officials attending included HCM City Vice Chairman Tran Van Bay, Major General Duong Duc Hai, head of the ministry's Fire Prevention, Fighting and Rescue Police Department (C07), and Major General Nguyen Thanh Huong, deputy director of HCM City Police.
Hai said petrochemical facilities required stringent safety standards because fires, explosions and other serious incidents could threaten lives, property, the environment and industrial operations.
He said the exercise was designed to test emergency response capabilities, command procedures and coordination between rescue teams, as well as the mobilisation of personnel and equipment.
Under the simulated scenario, lightning struck a pressure-relief valve on a butene-1 storage tank at 9.30 am while its lightning protection system was undergoing maintenance.
The strike ignited flammable vapours, triggering an explosion that severely damaged the tank and surrounding steel structures, equipment and pipelines, leaving five workers trapped beneath debris.
The blast also damaged three nearby petrol storage tanks, causing fuel to spill and ignite within the containment area. One tank was particularly badly affected, allowing the simulated fire to spread rapidly.
At the same time, a malfunctioning valve at the naphtha unloading terminal caused a sudden pressure surge, rupturing a connection between a ship and the unloading equipment.
About 5,000 litres of naphtha spilled onto the vessel's deck and into the water.
A spark from a dropped metal tool then ignited accumulated vapours, starting a fire that threatened the terminal and nearby pipelines.
Of the 36 crew members aboard, six were injured, six escaped in lifeboats and 24 jumped into the sea, where they drifted in the water.
In another simulated incident at the complex's central utility plant, a tanker unloading hydrochloric acid collided with a car, damaging a valve and releasing 80 litres of the chemical.
On-site firefighting teams activated emergency procedures, began initial containment operations and alerted professional rescue services.
The ministry's firefighting department subsequently coordinated the deployment of additional personnel and equipment to extinguish the simulated fires and rescue those trapped.
All simulated fires were brought under control and extinguished as planned.
At the end of the exercise, officials praised participating teams and called for a review of the operation to improve coordination and emergency response capabilities.