A joint operation uncovered an illegal mobile petrol station at Sau Mau Ping Estate in Kwun Tong on October 13, with about 900 litres of petrol seized.
The haul also included a fuel dispenser, an electric pump and the truck involved. The petrol was enough to fill the tanks of about 20 private cars.
The Hong Kong Fire Services Department said the truck lacked safeguards required at legal petrol stations. Electrical equipment was operating in the same compartment as the fuel, where petrol vapour could ignite if it met a spark or static electricity, causing a fire or explosion and putting estate residents at serious risk.
A truck driver was arrested at the scene on suspicion of offences under related laws. The case remained under investigation.