¶ 1 Arizona law exempts from use tax any “[m]achinery[ ] or equipment! ] used directly in manufacturing, processing, fabricating, ... or metallurgical operations.” Ariz.Rev.Stat. (“A.R.S.”) § 42-5159(B)(1) (Supp.2003).
1
Capitol Castings claimed that several items purchased for use in its foundry facilities qualified for the use tax exemption. The court of appeals, however, concluded that the items did not qualify for the exemption because they were not “machinery or equipment.”
See State ex rel. Ariz. Dep’t of Revenue v. Capitol Castings, Inc.,
BACKGROUND AND PROCEDURAL HISTORY
¶2 Capitol Castings manufactured grinding balls and custom-cast items used in mining and other industries. 2 Manufacturing these items entailed pouring molten metals and alloys into molds to form the desired shapes. Capitol constructed its molds using metal, silica sand, chemical binders, exothermic sleeves, mold cores, mold wash, and hot topping.
¶ 3 The molds for custom castings consisted almost entirely of sand. For some of the custom molds, Capitol would ram the sand for each half of the mold into a steel flat containing a wood pattern of the desired shapе. For other custom molds, Capitol would pom' sand treated with chemical binders over wood patterns. The binders helped the sand retain its form. Capitol would then insert into one of the custom casting mold’s halves an exothermic sleeve, a round tube that protruded from the mold like an exhaust pipe and retained excess molten metal that *447 became part of the casting as the metal inside cooled and cоntracted. Capitol used “hot topping,” a powder, to cover the end of the exothermic sleeve to keep the molten metal in the sleeve from cooling. After removing the wood patterns from the molds, Capitol sprayed the cavity left by the pattern in the mold with a mold wash to prevent the sand from sticking to the casting. Capitol sometimes used mold cores, also made of sand, to form cavities in the molds. Onсe the halves of each custom casting mold were complete, Capitol put the halves together to form a single mold.
¶ 4 Capitol’s molds were destroyed during the manufacturing process. The chemical binder and mold wash were completely consumed and the exothermic sleeves and hot topping were rendered unusable each time Capitol used a mold, but Capitol was able to salvage the metаl and sand for use in future molds.
¶ 5 The Arizona Department of Revenue (“ADOR”) did not contest the exemption for the metal molds, thus impliedly conceding that the metal molds are exempt from use tax, but it contends that the other materials — silica sand, chemical binders, hot topping, mold wash, mold cores, and exothermic sleeves — are not exempt.
¶ 6 ADOR also contests the exemption for the cement and lime Capitol used at its Chаndler facility to detoxify dust created by the arc furnaces used in the casting process. Like the chemical binders and hot topping, the cement and lime could not be reused after they were injected into the toxic dust.
¶ 7 Finally, ADOR contests the exemption for refractory materials, such as coxy sand and cerwool blankets, used to protect Capitol’s machinery and equipment from the extreme heat generated by its manufacturing processes. The manufacturing process destroyed the refractory materials, requiring Capitol to replace them periodically.
¶ 8 This case has an extensive procedural history, including two tax court proceedings, two published court of appeals opinions, and a legislative amendment to the exclusions from the exemptions afforded by A.R.S. § 42-5159(B). We will explain the history as it becomеs pertinent to the analysis.
DISCUSSION
A. Standard of Review
¶ 9 This case involves the interpretation of statutory provisions, matters that we review de novo.
See Bilke v. State,
¶ 10 In the tax field, we liberally construe statutes imposing taxes in favor of taxpayers and against the government,
Ariz. Tax Comm’n v. Dairy & Consumers Co-op. Ass’n,
B. Machinery or Equipment
¶ 11 Our analysis begins with the text of A.R.S. § 42-5159(B)(l), which exempts “[m]achinery, or equipment, used directly in manufacturing, processing, fabricating, job printing, refining or metallurgical operations.” The statute requires that the “terms ‘manufacturing,’ ‘processing,’ ‘fabricating,’ ‘job printing,’ ‘refining’ and ‘metallurgical’” be interpreted to include “those operations commonly understood within their ordinary meaning.” Id. No one disputes that Capitol’s casting processes were of the type contemplated by the statute.
¶ 12 The statute does not define the terms “machinery or equipment.” Generally accepted definitions of “machinery” indicate that it may be “an assemblage of machines,” “the parts of a machine collectively,” or “a system by which action is maintained or by which some result is obtained.” Webster’s College Dictionary 788 (2d ed.1997). The definition includes “an apparatus consisting of interrelated parts with separate functions, used in the performance of some kind of work,” or “a device that transmits or modifies force or motion.” Id. at 787. “Equipment” includes “the articles, implements, etc., used or needed for a specific purpose or activity.” Id. at 442.
¶ 13 Despite the lаck of definitional specificity in the statute, there is no dispute about its underlying purpose. The legislature enacted A.R.S. § 42-5159(B)(1) to stim ulate business investment in Arizona in order to improve the state’s economy and increase revenue from other taxes, such as income and property taxes.
See Ariz. Dep’t of Revenue v. Blue Line Distrib., Inc.,
¶ 14 Although the text of the statute may not clearly reveal the legislature’s intent, the procedural history of this case provides significant evidence of the legislature’s intended definition and its purpose in exempting machinery and equipment used in industrial processes frоm the use tax. In
Arizona Department of Revenue v. Capitol Castings, Inc.,
¶ 15 In the course of its “machinery or equipment” discussion, the court overruled the tax court’s opinion in
Arizona Department of Revenue v. Cyprus Sierrita Corp.,
¶ 16 In response to
Capitol I,
the legislature amended § 42-5159(C)(1), which excludes expendable materials from the (B)(1) use tax exemрtion, to provide that “expenda
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ble materials do not include any of the categories of tangible personal property specified in subsection B of [§ 42-5159]
regardless of the cost or useful life of that property.”
See 1999 Ariz. Sess. Laws, ch. 153, § 2 (emphasis added). The amendment plainly was designed to avoid the interpretation given to the prior version of subsection (C)(1) in
Capitol I.
As evidenced by the parties’ arguments, however, there remains a question whether the amendment of the (C)(1) exclusiоn also affects the analysis in
Capitol I
of § 42-5159(B)(1), the provision exempting certain machinery or equipment from the use tax. In
Capitol II,
the court of appeals held that the amendment did not affect the machinery or equipment analysis under subsection (B)(1).
¶ 17 The court of appeals reasoned in
Capitol II
that its opinion in
Capitol I
contained two parts: one that “rejected the broad interpretation of ‘machinery or equipment,’ ”
id.
at 264, ¶ 24,
¶ 18 Several factors demonstrate that, in amending A.R.S. § 42-5159(C)(1), the legislature meant to alter the specific result reаched by the court of appeals in
Capitol I,
not just the conclusion that the materials at issue were expendable and therefore excluded from the exemption. First is the language of the amendment itself. The conclusion in
Capitol I
that the items at issue did not qualify as machinery or equipment was ultimately grounded on the fact that the items were expended in the casting process.
¶ 19 Second, the legislative history of the amendment reveals that the legislature meant to change the result of Capitol I. Minutes of Senate Committee on Finance, 44th Leg., 1st Reg. Sess. (Feb. 22, 1999) (discussing the case law addressing the exemption for machinery or equipment and the exclusion for expendable materials); Senate Fact Sheet for H.B. 2395, 44th Leg., 1st Reg. Sess. (Feb. 18, 1999) (same); Minutes of House of Representatives Committee on Ways and Means, 44th Leg., 1st Reg. Sess. (Jan. 26, 1999) (same); House of Representatives Abstract for H.B. 2395, 44th Leg., 1st Reg. Sess. (1999) (same). We are therefore reluctant to read the amendment as leaving unaltered the ultimate result in Capitol I.
¶ 20 Finally, the legislature made the amendment retroactive to May 19, 1977,
see
1999 Ariz. Sess. Laws, ch. 153, § 3(A), the same day the court of appeals issued its opinion in
Duval Sierrita,
which had applied broader, function-based tests to determine whether items used in mining processes were exempt from use tax — an opinion distinguished in
Capitol I.
See
¶ 21 Although the items for which exemption was sought in
Duval Sierrita
differ from those at issue in this case, the approaches
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developed in that case provide a useful framework for analyzing whether an item is exempt under § 42-5159(B)(1). In
Duval Sierrita,
the court addressed whether two types of property qualified for the § 42-5159(B)(1) use tax exemption: (1) spare or replacement parts for items conceded to be machinery оr equipment,
¶ 22 While § 42-5159(B)(1), by its terms, applies only to “machinery” or “equipment” that is “used directly in manufacturing ... operations,”
Duval Sierrita
clarifies that whether an item qualifies as “machinery or equipment” must be considered in light of the second element of the exemption, that it be “used directly” in a manufacturing or other qualifying process. For example, a computer used in a business is “machinery” or “equipment.” A computer used purely for administrative purposes, however, may not qualify for the exemption because it is not “used dirеctly in manufacturing ... operations.” But if the computer is used to manage and control specific tasks conducted on an automated assembly line, the computer may well qualify for the exemption as it is “used directly in manufacturing ... operations.” Similarly, certain items not traditionally considered to be machinery or equipment may qualify as such depending on their function in the process. For example, in
Cyprus Sierrita,
the tax court fоund that three chemicals, “sulfuric acid, LIX, and Or-fom 7,” qualified as machinery or equipment.
¶ 23 As these examples show, a functional approach requires consideration of both of the exemption’s elements, as neither element standing alone may be dispositive. By embracing Duval Sierrita and its ultimate function and integrated rule tests, the legislature expressed its intent to extend the exemption for machinery or equipment beyond the narrow confines created by Capitol I.
¶ 24 From this evidence, we conclude that the 1999 amendment was specifically intended to overrule
Capitol I
and to reinstate the
Duval Sierrita
tests. Thus, in analyzing whether an item is exempt from use tax under § 42-5159(B)(1), a court should consider a number of factors to determine whether the item qualifies as “[m]achinery, or equipment, used directly in manufacturing ... operations.” First, a court must apply flexible and commonly used definitions of machinery and equipment within the relevant industry.
See supra
¶ 12. In determining whether the items at issue here were machinery or equipment, the court of аppeals in
Capitol I
relied upon the concept of “fixed assets,” which it defined as “physical resources” such as “machinery or tools” other
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than land and buildings.
¶25 Next, bearing in mind these flexible definitions, a court should examine the nature of the item and its role in the operations. Items essential or necessary to the completion of the finished product are more likely to be exempt. See
Duval Sierrita,
¶ 26 Applying these tests to the items at issue in this case, we conclude that the silica sand, chemical binders, exothermic sleeves, mold cores, mоld wash, and hot topping qualify for the exemption because they were used directly in and were an integral part of a qualifying process under A.R.S. § 42-5159(B)(1). The items functioned the way machinery or equipment might in an integrated, synchronized system within the industry. All had a close nexus to the process as they directly touched the raw materials in the process of converting them into the finished product. The cement and lime, on the other hand, aрpear to have served the ancillary purpose of pollution control and therefore were not as integrally related to the process. We conclude, therefore, that the cement and lime do not qualify for the exemption.
¶ 27 The record is less clear with respect to the coxy sand and cerwool blankets that were used as refractory materials. We remand to the tax court to determine whether these items qualify for exemption pursuant to A.R.S. § 42-5159(B)(1).
CONCLUSION
¶ 28 We conclude that the court of appeals interpreted the amendment to A.R.S. § 42- *452 5159(C)(1) too narrowly and the tax court similarly erred in its analysis in this case. We vacate the opinion of the court of appeals, reverse the decision of the tax court, and remand the case to the tax court for entry of judgment as to the decided issues and for further proceedings consistent with this opinion.
Notes
. The legislature renumbered § 42-1409(B)(1) as § 42-5159(B)(1) in 1997, see 1997 Ariz. Sess. Laws, ch. 150, §§ 107, 110, but made no substantive change to its language. Because there was no substantive change, this opinion refers to the current citation.
. Capitol no longer owns the foundry facilities discussed in this opinion.
. Citing
People's Choice TV Corp.,
. ADOR's failure to challenge the exemption for the metal components of the molds suggests that both the metal and the sand used in the grinding ball molds should qualify for the exemption, because both the metal and sand components seem to have performed the same functions. In an "integrated synchronized system," it does not seem logical that two items performing the same function, but composed of different materials, should be treated differently for purposes of the exemption afforded by § 42-5159(B)(1).
. ADOR’s concession that the molds would have qualified as machinery or equipment had Capitol purchased them preassembled, but not if Capitol assembled the molds itself, frustrates the legislative goal of the exemption and fails to apply Duval Sierrita’s ultimate function test.
