Concerned agencies have warned of fire and explosion hazards in Vietnam's first underwater tunnel that is set to open to traffic on November 22.
They have called for proper preventive measures as well as detailed rescue plans to drawn up in case accidents take place in the tunnel.
The warnings were issued at a meeting on Thursday where Ho Chi Minh City's firefighting police department and related agencies discussed emergency situations in the Thu Thiem Tunnel, which crosses under the Saigon River.
Nguyen Quang Nhat, chief of the firefight department's rescue division, said risks would be posed by sparks from vehicles' engines and cigarette ashes carelessly left by vehicle riders and even tunnel maintenance staff.
Meanwhile, various inflammable substances would be transported in vehicles travelling through the tunnel and some of the decorative items in it could be exposed to fire, he added.
However, Nhat said, the greater concern is that once a fire breaks out, it will spread very quickly and be accompanied by smoke and toxic gases, making it difficult for people to escape and also causing difficulties for firefighters.
Worse still, as the high temperature lasts, the possibility rises of the whole structure collapsing, he said.
The official also calculated that since the tunnel can accommodate up to 150 cars and 300 motorbikes, or between 500-800 people at peak time, fires and explosions could cause great damages to human life and property.
Nguyen Vu Son, deputy head of the division, stressed that devices detecting explosives in vehicles need to be put in place, because "although we have already banned vehicles transporting explosives via the tunnel, we shouldn't ignore explosion risks coming from vehicles' fuel."
The official also warned that when a fire takes place, electricity shouldn't be cut, because it will leave no light for firefighters to conduct their mission.
Son said that they are considering firefighting plans using inert gas and specialized trucks instead of water, because if the amount of water used to extinguish fire exceeds the tunnel's designed capacity, it will be flooded.
Water will be used to cool down firefighters, he said.
Local agencies plan to hold a firefighting exercise inside the Thu Thiem tunnel on October 22.
With construction completed last September after five years of work, Thu Thiem Tunnel links the city's Districts 1 and 2, and is a major part of the East West Highway Project.
Its part under the Saigon River comprises four sections, each of which is 92 meters long and weighs more than 27,000 tons.
It is designed to accommodate vehicles travelling up to 60 kilometers per hour.