delivered the opinion of the court:
Plaintiff-taxpayer, Clark Oil & Refining Corporation, brought this tax protest action against J. Thomas Johnson, Director of the Department of Revenue of the State of Illinois, and James H. Donnewald, State Treasurer of the State of Illinois, to contest the validity of use taxes assessed against it. The $11,045,087.25 in taxes and interest for the period July 1, 1978, to June 30, 1981, were paid by Clark Oil under protest pursuant to “An Act in relation to the payment and disposition of moneys received ***” (the Monies Act) (111. Rev. Stat. 1981, ch. 127, par. 170 et seq.). The taxes were assessed on Clark Oil’s use of certain “refinery fuels,” which are products created incidentally to the oil-refining process. Following a bench trial, the trial court upheld the validity of the assessment, but provided for the return of $291,037.14 to Clark Oil due to an error in computation made by the Department of Revenue. Clark Oil appeals. The gist of the arguments raised by Clark Oil are that (1) the Use Tax Act (Act) (111. Rev. Stat. 1981, ch. 120, par. 439.1 et seq.) is unconstitutionally vague as applied; (2) the Department of Revenue’s formula for calculating the use tax was unreasonable; (3) Public Act 83 — 614, which amended the Use Tax Act, should be applied here; and (4) the actual calculations made by the Department were arbitrary. We affirm.
During the taxable period at issue, Clark Oil purchased crude oil for the purpose of refining it into various marketable products at its Blue Island and Wood River refineries located in Illinois. The purpose of refining is to produce as many marketable products, and as much of such products, as is possible. Under current technology, however, three products which have little or no marketability are invariably produced during the refining process. These products are catalytic coke, process gas, and heavy oil, and they are sometimes generally referred to as refinery fuels because refineries have developed techniques to use them as energy sources for the refining process.
The presence of refinery fuels in the refineries may be briefly described as follows. At the beginning of the refining process, the crude oil is heated to a high temperature, and it travels to an atmospheric tower where a separation of components occurs. Some of these components proceed to a vacuum unit where vacuum gas oil is separated out and sent to the catalytic cracker or Fluid Catalytic Cracking unit (FCC). In the FCC unit, a catalyst, which is a very fine powder, is in constant motion, and it promotes the breakdown (or “cracking”) of the molecules in the vacuum gas oil. As this process occurs, catalytic coke adheres to the catalyst, with the result that the catalyst is neutralized. Consequently, it is necessary to remove the catalytic coke from the catalyst. To this end, the catalytic coke is burned off and thereby converted into flue gas. The flue gas is then captured and used as an energy source to generate heat which is used in the refining process. There is no market for catalytic coke, and, therefore, catalytic coke has no market value.
Process gas is generated at various stages of the refining process. A substantial part of the process gas is captured and becomes an energy source when it is burned in heaters at various processing units. At times, more process gas is created than can be utilized, and in order not to violate Environmental Protection Agency regulations, Clark Oil flares the excess process gas, thereby dissipating it. Clark Oil does not derive any heat value from such flaring. Since Clark Oil’s refineries are not proximate to facilities which use process gas as an energy source, it has no market for the process gas.
The third product which results from the refining process that is subject to the use tax is heavy oil. Some of the heavy oil which is produced is marketed. When the heavy oil is combined with a lower viscosity dilutant, it is sold by Clark Oil as No. 6 fuel oil. Also, some heavy oil is sold for use in asphalt products. Clark Oil uses heavy oil generated during the refining process when there is insufficient process gas available to satisfy a refinery’s heating needs. In such situations, heavy oil is burned when it would be cheaper to do so than to purchase natural gas to meet heating demands.
The use tax at issue here was assessed by the Department pursuant to the Use Tax Act (111. Rev. Stat. 1981, ch. 120, par. 439.1 et seq.) on Clark Oil’s use of its refinery fuels for heating purposes. The formula used by the Department to compute the tax was essentially based upon the difference between the volume of the crude oil purchased and the volume of marketable production adjusted for the expansion which occurs during the refining process, measured by the purchase price of the crude oil.
In its first argument, Clark Oil contends that the Use Tax Act is unconstitutionally vague to the extent that it does not provide how the selling price, 1 which is the measure of the tax due, should be allocated where, as here, the two parts of the purchased property are not physically the same. Under section 3 of the Use Tax Act (111. Rev. Stat. 1981, ch. 120, par. 439.3), “[a] tax is imposed upon the privilege of using in this State tangible personal property *** purchased at retail from a retailer. Such tax is at the rate of 4% of the selling price of such property.” Section 2 of the Act defines selling price as “the consideration for a sale valued in money.” 111. Rev. Stat. 1981, ch. 120, par. 439.2.
A legislative enactment is unconstitutionally vague if its terms are so indefinite that persons of common intelligence must necessarily guess at its meaning and differ as to its application. (Fagiano v. Police Board (1983),
Moreover, in Mobil Oil Corp. v. Johnson (1982),
In further challenging the constitutionality of the use tax, Clark Oil contends that the Act impermissibly delegates legislative authority to the Department, in that the Department has too much discretion in determining the method of assessing the tax. We disagree. The legislature determined that the basis for computing the use tax is the selling price. The Department is vested with broad powers to administer the Use Tax Act (See 111. Rev. Stat. 1981, ch. 120, par. 611; 111. Rev. Stat. 1981, ch. 127, par. 39b28), and implicit in the powers granted to it in the Act and elsewhere in the statutes is the authority to establish the method by which use taxes are to be calculated. It has been recognized that “[t]he legislature cannot deal with the details of every particular case, and reasonable discretion as to the manner of executing a law must necessarily be given to administrative officers.” (Department of Finance v. Cohen (1938),
Next, in a series of related arguments, Clark Oil contends that allocation of the selling price on the basis of relative volume is unreasonable. Clark Oil suggests alternative methods of computing the use tax which it claims that the legislature should be deemed to have contemplated since these methods comport with well-accepted accounting principles. Clark Oil states that it is unreasonable to suppose that it intended to pay as much per unit of volume for the part of the crude oil which became refinery fuels as it did for the part which became marketable production and, therefore, relative volume should not be the basis for allocating the selling price. Rather, Clark Oil argues, the allocation should be made on the basis of regression analysis or relative sales value, since either of these methods would provide a more economically sound basis for computing the tax.
According to Clark Oil’s expert, regression analysis is a statistical technique for identifying relationships between two or more variables in some substances. It is a statistical tool used in the calculation of implicit prices. As an example, if a man purchased a car for $10,000 on the basis of its roominess and its horsepower, the implicit price would have to do with how much was paid for the one attribute and how much was paid for the other. If this method were to be applied in the present case, Clark Oil would not owe any use tax on its use of process gas and catalytic coke because no part of the “selling price” it paid for the crude oil was paid for those substances. There is no evidence in the record as to the amount of tax that would be due on • the heavy oil burned under regression analysis.
Under Clark Oil’s alternative theory of computation, relative sales value, the cost assigned to each product is based upon its relative share of the total amounts received when all of the products are sold. Since catalytic coke and process gas are not sold, they have no market value, and no tax could be assessed on their use. Further, since the market value of heavy oil is substantially lower than the market value of the other marketable products produced from crude oil, the heavy oil would be assigned a cost below that of the crude oil.
We believe that the Mobil Oil decision is dispositive of the arguments raised by Clark Oil. In Mobil Oil, the supreme court approved the relative volume approach used by the Department. In so doing, the court rejected Mobil Oil’s argument that the relative sales value approach should be utilized. (Mobil Oil Corp. v. Johnson (1982),
Furthermore, we are unpersuaded by Clark Oil’s argument that Public Act 83 — 614, which amended section 3 of the Use Tax Act, shows the legislature’s intent that the relative sales value approach must be used. The amendment, which occurred following the Mobil Oil decision, provided that the tax is to be imposed at a rate of the stated percentage of either the selling price or the fair market value, if any. More specifically, the amendment provided, “In all cases wherein property functionally used or consumed is a by-product or waste product which has been refined, manufactured or produced from property purchased at retail, then the tax is imposed on tjje lower of the fair market value, if any, of the specific property so used in this State or on the selling price of the property purchased at retail.” (Emphasis added.) (111. Rev. Stat. 1985, ch. 120, par. 439.3.) This amendment became effective on January 1, 1984. Clark Oil argues that the amendment is applicable here because it did not change existing law but merely clarified the law as it existed before. We disagree. The amendment did not merely clarify existing law, but actually changed it. Contrary to Clark Oil’s argument, the amendment does not demonstrate that the selling price is to be measured by the fair market value. Rather, the amendment retains the selling price as a valid measure of the use tax but, in addition, it provides that the fair market value is to be an alternative measure of the use tax. While the legislature could have provided a means of determining selling price other than on the basis of relative volume, it clearly did not choose to do so.
Moreover, we must reject Clark Oil’s argument, based on General Telephone Co. v. Johnson (1984),
Next, Clark Oil argues that the Department’s construction of the Act is discriminatory and violates Clark Oil’s right to equal protection because it taxes the waste of a purchaser-user while not taxing the waste of a purchaser-reseller. We find this argument to be untenable. Clark Oil was not taxed on its waste but on its intentional use of refinery fuels. Although Clark Oil may, for various business purposes, identify refinery fuels as waste, such a denomination does not alter the fact that Clark Oil purposely utilized the refinery fuels for heating purposes. The privilege of using this tangible personal property was clearly subject to taxation under the Use Tax Act. We therefore find no basis for Clark Oil’s equal protection argument.
Clark Oil further posits that use of the relative volume approach results in double taxation. Double taxation exists where two taxes are imposed for the same period of time, for the same purpose, upon the same property, and by the same taxing authority. (See People ex rel. Bernardi v. Bethune Plaza, Inc. (1984),
We agree with the trial court’s finding that the fact that Clark Oil raised the price of its premium products to cover the full cost of the crude oil does not demonstrate double taxation. As the trial court recognized, this is not the legal criterion for determination that there has been impermissible double taxation. Nor did Clark Oil prove that the same property was actually taxed twice. Its conclusory statement that it was taxed twice on the crude oil is insufficient to establish its claim that such double taxation occurred.
In its final argument, Clark Oil contends that the formula devised by the Department to determine which part of the crude oil became refinery fuels and which part became marketable products was unworkable in practice and improperly applied by the Department. According to Clark Oil, the Department’s formula did not take into account the loss of process gas due to flaring, did not take into account the costs of inputs other than the crude oil and, most importantly, the 4% expansion figure used by the Department was arbitrary and capricious. The formula used by the Department in establishing the relative volumes of those parts of the crude oil which became refinery fuels and those parts which became marketable products was expressed by Clark Oil as follows:
barrels = barrels of inputs - barrels of marketable production
consumed expansion factor
Under section 4 of the Retailers’ Occupation Tax Act, the Department’s correction of a taxpayer’s return according to its “best judgment and information” is prima facie correct and is prima facie evidence of the correctness of the tax due. (111. Rev. Stat. 1981, ch. 120, par. 443.) This provision is applicable to the Use Tax Act. (See 111. Rev. Stat. 1981, ch. 120, par. 439.12.) The method employed by the Department in correcting a taxpayer’s return must meet a minimum standard of reasonableness. (See Masini v. Department of Revenue (1978),
The record shows that the formula devised by the Department evolved after the Department’s discussions with Mobil Oil and an outside consultant, Data Graphics, and it reflects the Department’s experience in auditing other oil companies. As for the problems of which Clark Oil complains, we must agree with the trial court that the basis for the problems here was Clark Oil’s failure to provide the Department with the appropriate, relevant data. The record shows that Clark Oil was familiar with the formula in that Clark Oil was in communication with Mobil Oil during Mobil Oil’s audit in order to assist Mobil Oil. Furthermore, the Department advised Clark Oil of the formula and the data that it would need in order to conduct its audit. Although there was conflicting testimony as to what data was requested, the conflicts merely raised questions of credibility which the trial court decided in favor of the Department. The fact is that Clark Oil was aware of the information necessary for the completion of the audit, yet only supplied the Department with a single yield report which contained but a portion of the information which was required. Clark Oil also made no effort to explain the information which it did provide to the Department, although it now faults the Department for failing to understand some of this information.
Regarding the specific problems raised by Clark Oil, the record shows that Clark Oil never informed the Department of the cost of the inputs other than the crude oil. Also, Clark Oil never provided the Department with any information regarding the amount of process gas which was flared and thus not subject to taxation. As for Clark Oil’s main contention, that the 4% expansion figure was arbitrary, the record shows that the Department was put in the position of having to estimate this figure because of Clark Oil’s lack of cooperation. We do not believe that this figure is so arbitrary that it cannot be sustained. During its audit of Mobil Oil, the Department determined that the expansion factor in the refining process is generally between 3% and 7%. The expansion factor refers to the fact that as a result of the refining process, chemical reactions take place which create molecular structures that occupy more physical space than that occupied by the original oil. The Department determined that the expansion rate for Mobil Oil was 4.5%. In the present case, the Department adjusted the rate down to only 4% on the basis that Clark Oil’s refineries are older than Mobil Oil’s and therefore likely to be less efficient. While it is true that Clark Oil presented evidence that there can be negative expansion, one of Clark Oil’s witnesses testified on cross-examination that for the taxable period, Clark Oil’s reports show that the expansion was significantly higher than 4%. Finally, we agree with the Department that the record does not support Clark Oil’s claim that the Department improperly utilized an overall expansion rate rather than the marketable production expansion rate when it made its calculations.
Once the Department established its prima facie case, the burden shifted to Clark Oil to overcome it. It was incumbent upon Clark Oil to produce books and records showing that the Department’s corrected returns were in error. (Masini v. Department of Revenue (1978),
Accordingly, the judgment of the trial court is affirmed.
Affirmed.
WHITE and FREEMAN, * JJ., concur.
