The important part of the samples, which are analysed in CTL are goods which belongs to the heading 2710 of Harmonised System including petroleum products, mineral oils and oils obtained from bituminous minerals. Although all these products are similar in both their composition and physical properties, the different excise tax is applied depending on their purpose of use. This results in the case of incorrect goods declaration to the high tax evasions. That is the reason for the equipment of CTL with the special apparatus for the analysis of petroleum products.
According to the supplementary notes of the chapter 27 (HS), mineral oils are classified on the basis of the results of distillation tests into light oils, medium and heavy oils including petroleum spirits, kerosene and gas oils, heating oils and lubricating oils, respectively. That is why CTL is equipped with the automatic distilling instruments.
Other equipment for the determination of the parameters of petroleum compounds, which are mentioned in the supplementary notes (1) in the chapter 27 of the Harmonised System for their classification into the corresponding subheadings and for purpose of Excise Tax Act include:
- X-ray-fluorescence and UV-fluorescence spectrometers for the determination of sulphur content.
- Instruments for the determination of flash point in open or closed cup testers.
- Capillary Ubbelohde and Stabinger type viscometers.
- Instrument for pour and cloud points and cold filter plugging point (CFPP) measurements.
- The testing engine for determination of the knock characteristic of motors by the research method (octane number of motor gasolines).
- HPLC for determination of marking substances.
In 1993 and 1994 in the Czech Republic considerable tax evasions occured due to customs declaration of petroleum products by exchange of diesel for light heating oils. Act No. 136/94 Sb. (novelised with 214/96 Sb. and 443/2003 Sb.) on colouring and marking of certain hydrocarbonate fuels and lubricants came into force in 1.7.1994 in order to prevent these evasions. According to this Act the colouring and marking of medium, gas, heating and certain lubricating oils, which are not used as fuels in the ignition engines, with colouring and marking preparates was introduced.
Regular examination of imported products by the customs bodies and the customs laboratories according to the Act on colouring and marking was in practice very effective. While during first 6 months of 1994 the importation of critical petroleum products culminated (about 170 000 tons of light heating oils per month was imported), since the above mentioned Act came into force, the importation was reduced under 20 000 tons per month and the sale of diesel produced in the Czech refineries increased rapidly. It can be seen, that the Act on Colouring and Marking and its regular examination in the Customs Technical Laboratories had a positive influence on the tax system of the Czech Republic, the refineries and distributors economics as well as on the environment.