Turkish police organized crime and smuggling units launched operations in seven cities against producers and sellers of "10 Numara" (Number 10) oil lubricant, a dangerous imitation material used as cheap fuel in vehicles.Twenty-four suspects were detained in raids on Friday after three months of surveillance of dealers in the southern city of Antalya. Operations were expanded to the cities of Van, Burdur, Yozgat, Erzurum, Elazığ and Sivas after police discovered the presence of a gang specializing in the oil lubricants in those cities.Along with the suspects, police seized 13,000 liters of the knock-off oil. Suspects are accused of producing and selling the lubricant, the use and production of which are illegal.The oil lubricant is blamed for a string of accidents in recent years where vehicles' engines caught fire due to the inflammable nature of this type of oil lubricant, which is preferred as a cheaper substitute to regular diesel fuel. 10 Numara oil lubricant, named after its grade of viscosity, is known for shortening the lifetime of a vehicle's engine and is only used in buses, trucks and similar vehicles. It is also known as a major pollutant of the environment due to its high toxicity and harmful emissions from the vehicles running on the material. The government raised taxes on oil lubricant used in heavy industrial equipment and printing presses to deter illegal use. Inspections also increased in gas stations that secretly sell the lubricant to drivers, but experts say an underground sector flourishes, and called on the authorities to increase inspections of vehicles rather than gas stations and to impose effective fines on its users.