THE NUMBER of criminal prosecutions for illegally parked vehicles carrying liquefied petroleum gas (LPG) cylinders and for excessive gas storage this year has already exceeded the total figure for 1992. The crackdown on the storage and carriage of dangerous gas followed an LPG explosion in Tuen Mun on September 30 last year. One lorry carrying LPG and another carrying kerosene exploded in crowded Tsing Hang Path, wrecking a car park full of vehicles, sending twisted metal flying and injuring five people. One direct result of the blast was an added safety measure which, by the end of this month, will stop the 900 LPG carriers in Hong Kong from transporting LPG and kerosene at the same time. The Electrical and Mechanical Services Department launched a blitz which resulted in 36 prosecutions or pending prosecutions. This compares to 33 cases for the whole of 1992. The Fire Services Department has received 551 complaints from the public about gas cylinders since last October. Gas safety and enforcement chief engineer Keith Whittle said illegal parking and excessive storage of LPG cylinders, especially by restaurants, was a problem in Hong Kong. ''I would be happy if there were no prosecutions,'' he said. ''I think the problem comes from the fact that these people have a job to do. ''The distributors have to supply the cylinders from the oil companies and it is very difficult due to the shortage of space in Hong Kong.'' Mr Whittle said 650,000 families relied on LPG for cooking and hot water. He said that after the explosion the Electrical and Mechanical Services Department and the Fire Services Department agreed to ban the carrying of LPG and kerosene together. It has taken one year to phase out Type A permits which allow for dual carriage. Mr Whittle said the Electrical and Mechanical Services Department was waiting for an answer from oil companies about proposed sites for parking. He hoped the sites would lead to the abolition of the rule that allowed vehicles carrying LPG to be parked 15 metres from buildings overnight in a non-congested area. Those who parked illegally can be fined a maximum of $5,000. Illegal storage carries a maximum fine of $25,000 and up to six months' jail. People who repeatedly break the storage rule can be fined $2,000 for each day they contravene the law. Dr Tang Siu-pong, elected legislator for New Territories West, applauded the increased prosecutions and crackdown on dual carrying. But he urged those concerned to reach a quick solution on a site for parking LPG vehicles. He said the supplier, not the retailer, should be responsible for parking. Tuen Mun Assistant District Commander (Crime) Superintendent Ray Pierce said the explosion was still being investigated. Police have ruled out the possibility of triad extortion and the involvement of children. They believed the explosion was an accident but said people could still be held criminally responsible for recklessness, he said.