Sanders, J.
We hold that actions which are categorically exempt from review under the State Environmental Policy Act of 1971 are in fact exempt.
Boise Cascade Corporation and other pulp and paper mills (mills) appeal a superior court order remanding re-issuance of their mills’ waste water discharge permits to the Pollution Control Hearings Board to determine [348]*348whether these permits constitute a "major action” under the State Environmental Policy Act of 1971 (SEPA), RCW 43.21C.110(l)(a), notwithstanding their categorical exemption. WAC 197-11-855(1) (hereinafter "categorical exemption”). The mills claim this is error, asserting "categorical exemption” means just that. Because of the great public importance for a reliable system of categorical exemptions, and the need for the orderly and cost effective administration of SEPA, we granted direct review and reverse, holding actions classified as categorically exempt are immune from SEPA review.
Although this case is now moot, the issues have been well briefed and we reach the merits because the reliability of the system of categorical exemptions under SEPA is a matter of continuing and substantial public interest requiring our determination.
STATEMENT OF FACTS
The Pollution Control Hearings Board (PCHB) and the Thurston County Superior Court did not reach any of the factual issues or make any factual determinations regarding the SEPA claims. The SEPA issues were decided below solely as a matter of law.
Procedural History
The procedural history of this case is long and convoluted. The Department of Ecology (hereinafter "Ecology”) reissued National Pollutant Discharge Elimination System (NPDES) permits to the mills between May and July 1991. Both the mills and environmental advocacy groups (hereinafter "Dioxin”) cross-appealed various aspects of the permits. This is the third time issues involving these particular permits have come before this court.
In the first case, Simpson Tacoma Kraft Co. v. Department of Ecology, 119 Wn.2d 640, 835 P.2d 1030 (1992), the mills challenged Ecology’s adoption of the numeric water [349]*349quality standards and permit conditions limiting dioxin levels. The mills appealed to the PCHB and Dioxin intervened. The PCHB vacated the standards set by Ecology limiting dioxin levels in the mills’ permits. Ecology then appealed to the Thurston County Superior Court which affirmed the PCHB and invalidated the dioxin limitation rule because Ecology failed to follow proper rule-making procedures. This court accepted direct review and affirmed. Simpson, 119 Wn.2d 640.
In the second case, Dioxin/ Organochlorine Ctr. v. Department of Ecology, 119 Wn.2d 761, 837 P.2d 1007 (1992), Dioxin/Organochlorine Center, Columbia River United, Inc. and Puget Soundkeeper Alliance (collectively "plaintiffs” or "Dioxin I”) commenced a two-pronged attack alleging that Ecology improperly failed to conduct a SEPA review prior to issuance of the NPDES permits to the mills. In its first prong Dioxin filed a complaint in Thurston County Superior Court seeking declaratory and injunctive relief. The superior court dismissed Dioxin’s complaint for failure to exhaust administrative remedies. This court accepted direct review and affirmed, dismissing the case. Dioxin I, 119 Wn.2d 761.
But under the second prong Dioxin appealed issuance of one permit to the Pollution Control Hearings Board (PCHB), as a protective measure. The instant case results from this second prong of Dioxin’s attack. Dioxin challenged Ecology’s reissuance of one mill’s NPDES permit on SEPA grounds and intervened in the other mills’ NP-DES permit appeals. On May 15, 1992, the PCHB determined that Ecology’s regulatory exemption for waste discharge permits "[was] reasonably consistent with SEPA as a matter of law,” and granted partial summary judgment to Ecology on the SEPA claims. Clerk’s Papers at 11, Partial Summ. J. Order, PCHB No. 91-140 at 19-20 (5/15/ 92). Dioxin then appealed PCHB’s SEPA ruling to the Thurston County Superior Court which ruled that a categorical regulatory exemption would not prevent SEPA review if shown reissuance of the permits is a major ac[350]*350tion; i.e., having a probable significant, adverse environmental impact. That court remanded to the PCHB to make the factual determination of whether the reissuance of these permits was a "major action” with significant adverse environmental impacts notwithstanding the categorical regulatory exemptions. The mills sought and obtained direct review from this court.
No factual findings have been made as to whether the reissuance of these permits would be "major actions” having probable significant, adverse environmental impacts.
MOOTNESS
Since the permits at issue have either expired or will soon expire, and the Legislature has amended SEPA to categorically exempt the reissuance of NPDES permits by statute,1 the parties agree this case is technically moot as "A case is technically moot if the court cannot provide the basic relief originally sought,” Snohomish County v. State, 69 Wn. App. 655, 660, 850 P.2d 546 (1993) (citing In re Swanson, 115 Wn.2d 21, 24, 804 P.2d 1 (1990)), review denied, 123 Wn.2d 1003 (1994), "or can no longer provide effective relief,” Snohomish, 69 Wn. App. at 660 (citing In [351]*351re Cross, 99 Wn.2d 373, 376-77, 662 P.2d 828 (1983)). However this does not conclude our inquiry.
We may decide a moot case if it involves matters of continuing and substantial public interest. In re Swanson, 115 Wn.2d at 24.
In determining whether or not a sufficient public interest is involved, a court should consider:
(1) the public or private nature of the question presented; (2) the desirability of an authoritative determination which will provide future guidance to public officers; and (3) the likelihood that the question will recur.
Snohomish, 69 Wn. App. at 660 (quoting In re Swanson, 115 Wn.2d at 25).
Ecology and Dioxin take a narrow view of the issue and argue that determination of this case will not satisfy the second and third criteria because reissuance of NPDES permits will never be challenged under the State Environmental Policy Act of 1971 again. Ecology contends that since there have been only two other reported cases involving categorical exemptions in the last 13 years, issues involving categorical exemptions are unlikely to recur. On the other hand, the mills argue the Thurston County Superior Court’s decision in this case undermines the system of categorical exemptions by inviting case by case review of otherwise categorically exempt actions.
Applying the Swanson criteria, we find: (1) this is a matter of substantial public importance concerning public agency approval of public and private activities affecting the environment; (2) an authoritative determination by this court would provide project proponents, opponents, members of the public, agencies, and lower courts important guidance as to whether case-by-case review of proposals that fit within valid categorical exemptions is available; and (3) the issue is likely to recur because many [352]*352permit applications are for categorically exempt activities and, thus, the superior court’s action in this case is likely to encourage claims that projects are "major actions” requiring SEPA review. The uncertainty likely to result if "as applied” challenges are brought by new cases could take this court years to resolve, at tremendous expense to all those concerned. Furthermore, we initially accepted review in this case because of the important and unsettled question of whether categorically exempt actions, not merely NPDES permits, are subject to SEPA review and because the substantive issues have been well briefed by the parties and the advocacy is of high quality. Compare Snohomish County, 69 Wn. App. at 661. Therefore, we consider this matter to be of continuing and substantial public interest warranting final resolution and proceed to the merits for essentially the same reasons the Court of Appeals did so in Snohomish County, 69 Wn. App. at 660-61.
Standard of Review
The Thurston County Superior Court interpreted the SEPA statute as requiring case-by-case review of "major actions” without regard to their categorically exempt status. A court’s interpretation of a statute is inherently a question of law; this court reviews questions of law de novo. Smith v. Continental Cas. Co., 128 Wn.2d 73, 78, 904 P.2d 749 (1995).
SEPA
The central SEPA requirement is a threshold determination of environmental significance and, if an action is significant, the preparation of an environmental impact statement (EIS). RCW 43.21C.030. An EIS "shall be prepared . . . for . . . major actions having a probable significant, adverse environmental impact.” RCW 43.21C.031 (Supp. 1995). However, "[ajctions categorically exempt under RCW 43.21C.110(l)(a) do not require environmental [353]*353review or the preparation of an environmental impact statement under this chapter.” RCW 43.21C.031 (Supp. 1995).
The Department of Ecology was directed by the 1983 SEPA amendments to adopt "uniform rules and guidelines” interpreting and implementing SEPA. RCW 43-.21C.110(1) (amended by Laws of 1983, ch. 117, § 7). That statute defines Ecology’s rule-making authority to include, but not be limited to:
Categories of governmental actions which are not to be considered as potential major actions significantly affecting the quality of the environment .... The types of actions included as categorical exemptions in the rules shall be limited to those types which are not major actions significantly affecting the quality of the environment. The rules shall provide for circumstances where actions which potentially are categorically exempt require environmental review. An action that is categorically exempt under the rules adopted by the department may not be conditioned or denied under this chapter.
RCW 43.21C.110(l)(a) (Supp. 1995) (emphasis applied to language added by amendment (Laws of 1995, ch. 347, § 206)).2
SEPA Rules
RCW 43.21C.110(l)(a) categorically exempts a proposal if it fits within any of the provisions "in Part Nine of [the SEPA] rules,” WAC 197-11-305(1), unless (1) the proposal is not exempt under WAC 197-11-908, which applies to "environmentally sensitive areas,” WAC 197-ll-305(l)(a); [354]*354or (2) the proposal is a segment of a series of actions categorically exempt in part or is a segment of a series of exempt actions that together may have a probable significant, environmental impact. WAC 197-ll-305(l)(b)(i), (ii).
Categorical exemptions are set forth in WAC 197-11-800 through 890. Such actions do not require threshold determinations of environmental significance or preparation of an EIS, subject to the limitations of WAC 197-11-305. WAC 197-11-800. These categorical exemptions cover a broad range of government agency actions approving public and private activities, such as:
(1) Minor new construction—Flexible thresholds.
(b) The following types of construction shall be exempt, except when undertaken wholly or partly on lands covered by water:
(i) The construction ... of four dwelling units.
(ii) The construction of a barn ....
(iii) The construction of an office, school, commercial, recreational, service or storage building with 4,000 square feet of gross floor area ....
(iv) The construction of a parking lot designed for twenty automobiles.
(v) Any landfill or excavation of 100 cubic yards ....
(2) Other minor new construction. . . . bus stops, . . . minor road . . . improvements, . . . septic tank installations, . . . landscaping [and boundary markers].
(3) Repair, remodeling and maintenance activities.
(4) Water rights.
(5) Purchase or sale of real property.
[355]*355(6) Minor land use decisions. . . . short platting. . . [and minor zoning] variances.
(7) School closures.. . .
(8) Open burning.. . .
(9) Variances under the Clean Air Act. . . .
(10) Water quality certifications.. . .
(11) Activities of the state legislature.. . .
(12) Judicial activity.. . .
(13) Enforcement and inspections. . . .
(14) Business and other regulatory licenses.. . .
(15) Activities of agencies. . . .
(16) Financial assistance grants.. . .
(24) Utilities.. . .
(25) Natural resources management. . . . [such as small grazing, agricultural or forest leases, leases of moorings for pleasure boats].
WAC 197-11-800.
The SEPA rules also specify a broad list of exemptions and nonexemptions that apply to specific state agencies and are also subject to the limitations of WAC 197-11-305. WAC 197-11-810. For example, most licensing activities of the Department of Licensing are exempt from SEPA review, WAC 197-11-820; but the Department of Labor and Industries undertakes a "major action” when it adopts safety regulations addressing noise standards, WAC 197-11--825; the Department of Natural Resources can initiate forest closures in light of extreme fire hazards and issue permits to use power equipment on forest lands without SEPA review, WAC 197-11-830; the Department of Fisheries can establish fishing seasons and catch limits, WAC 197--11-835; the Department of Game can issue hunting licenses, permits, or tags, WAC 197-11-840; but the Department [356]*356of Social and Health Services may not approve final plans for construction of a nursing home or alcoholism treatment center without taking a "major action,” WAC 197-11--845.
Analysis of SEPA
The mills and the amici argue SEPA review is not required for an individual action that is properly categorized as exempt under a valid regulation, citing RCW 43.21C.031. We agree.
The mills reason: (1) an action may be challenged for failure to fit within a categorical exemption; (2) a categorical exemption itself may be challenged as over-broad on its face for including "types of actions” that are "major,” RCW 43.21C.110(l)(a); (3) but to allow an ad hoc factual inquiry into the environmental impact of a specific proposal or permit approval action is inconsistent with the requirements of RCW 43.21C.110(l)(a). The nub of the mills’ argument is "types of actions” may be reviewed to determine if the exemption itself is overbroad on its face as to the categories exempted, but individual "actions” within a properly exempt category may not be reviewed on a case by case basis under SEPA. On the other hand, Dioxin argues it is entitled to challenge the validity of a categorical exemption "as applied” to any specific permit if the issuance of the permit allows an activity (in this case, discharges of dioxin) which is assertedly a "major action” having a probable significant adverse environmental impact, rather than challenging the regulation as over-broad on its face.
The parties cite basically the same statutory provisions, particularly RCW 43.21C.110(l)(a), and legislative history in support of their respective positions. See Washington State Comm’n on Envtl. Policy, Ten Years’ Experience With SEPA: Final Report 106 (June 1983) (hereinafter "Final Report”), and Kenneth S. Weiner, Section-by-Section Summary of SSB 3006, reprinted in Richard L. [357]*357Settle, The Washington State Environmental Policy Act: A Legal and Policy Analysis App. B at 291 (1987). The mills further rely on two Court of Appeals cases: Snohomish County v. State, 69 Wn. App. 655, 668-69, 850 P.2d 546 (1993), review denied, 123 Wn.2d 1003, 868 P.2d 871 (1994), and Concerned Citizens of Hosp. Dist. No. 304 v. Board of Comm’rs of Pub. Hosp. Dist. No. 304, 78 Wn. App. 333, 345 n.1, 897 P.2d 1267 (case by case SEPA review not available), review denied, 127 Wn.2d 1024, 904 P.2d 1157 (1995). Dioxin relies on two other cases: Downtown Traffic Planning Comm. v. Royer, 26 Wn. App. 156, 612 P.2d 430 (1980), and Noel v. Cole, 98 Wn.2d 375, 655 P.2d 245 (1982).
The mills claim Downtown Traffic and Noel are no longer applicable because each was decided prior to the 1983 SEPA amendments. Dioxin claims the legislative history of the 1983 amendments to SEPA supports the continued authority of Downtown Traffic and Noel, so courts continue to have authority to review categorical exemptions "as applied.” Dioxin attempts to distinguish Snohomish claiming that it is based upon statutory categorical exemptions rather than administrative categorical exemptions. Additionally, Dioxin dismisses Concerned Citizens as dicta. Dioxin further argues that the purposes of categorical exemptions, reduction of paperwork, expense, and delay are served by the 1983 SEPA amendments because they allow agencies to rely on exemptions, but courts are to review those exemptions "as applied” on a case by case basis. Dioxin argues if it can prove the NPDES permit approvals are "major actions,” it is entitled to "partial invalidation” of the categorical exemption. The mills have the best of this argument.
In Downtown Traffic, the Court of Appeals, Division One, reviewed a City of Seattle proposal to establish exclusive bus lanes on two downtown streets and held the proposal could not be exempt (under a categorical exemption "guideline” for minor construction) from SEPA review, if it would have the allegedly major adverse environmental effect asserted by opponents.
[358]*358In Noel, this court found a categorical exemption "guideline” for a large logging project as overbroad. The parties conceded the exemption was overbroad "as applied.” It exempted all timber sales regardless of size or effect. This court said in a footnote: "At the least, administratively created exemptions [guidelines] must be construed to apply only when the particular action in question is not a major action significantly affecting the environment.” Noel, 98 Wn.2d at 381 n.2 (citing Downtown Traffic, 26 Wn. App. at 165).
However, in 1981, after Downtown Traffic, the Legislature created the Commission on Environmental Policy to review SEPA. See Final Report, supra. "The most obvious indicator of legislative intent, other than the words of the statute itself, is the Commission’s own report and explanation of its proposals.” Id. at 19; accord Waterford Place Condominium Ass’n v. City of Seattle, 58 Wn. App. 39, 49, 791 P.2d 908, review denied, 115 Wn.2d 1019, 802 P.2d 126 (1990). The rules were proposed with the legislation, so "[t]he rule recommendations themselves, therefore, contribute to an understanding of legislative intent.” Final Report at 20. The Final Report expressly addresses the question at hand and supports the position advanced by the mills:
The amendment . . . stat[es] that categorically exempt actions do not require environmental review. The amendment was intended to clarify and emphasize the legislative intent since 1974 . . . The legislative history and the rejection of proposed committee amendments make clear that agencies are not required to examine whether a given proposal has a significant impact . . . even though some recent cases have implied that agencies might have to do so [an apparent reference to Downtown Traffic and Noel] (the reason for having a system of categorical exemptions is to eliminate the need for individual environmental review).
Final Report at 29 (emphasis added).
Some confusion has arisen in situations where courts have been confronted with proposals having significant impacts, [359]*359but an agency asserts the proposal is categorically exempt. In such cases, the courts are faced with two questions (the answer to the first will usually resolve the issue): (1) does the proposal fit within the asserted exemption . . . and if so, (2) does the type of action exempted by the rules result in significant adverse environmental impacts. If the answer to the second question is affirmative, the exemption in the rules would be overbroad. Judging by the tone (not the results) of a few judicial opinions, the state courts have not always recognized that the importance of a reliable and efficient system of categorical exemptions is such that it would be better in the rare instance to find an exemption overbroad, than to require individual case-by-case environmental review on every governmental activity. Such individual review would defeat the very purpose of having categorical exemptions and would create an immense paperwork, bureaucratic, and cost burden on government and taxpayers.
Settle, supra, app. B at 306 (emphasis added).
Both parties cite the colloquy on the senate floor between Senator Bottigner and Senator Bluechel, the commission chairman, on the categorical exemptions provisions of Senate Substitute Bill 3006.
This exchange indicates that the Legislature intended that applicants, not just agencies (as Dioxin argues), be able to rely on the system of categorical exemptions.3 Furthermore, the distinction drawn in the colloquy between a "type of action” and a "specific proposed action” further supports the view that case by case review of specific permit approvals, otherwise categorically exempt, was not legislatively intended.
The preface to the proposed rules rejected opening cate[360]*360gorical exemptions to "proposal-by-proposal” impact consideration. Preface to the Proposed Rules, Final Report at 86.4
The section by section analysis of the proposed SEPA rules suggests the commission, and the Legislature considered Downtown Traffic to be wrongly decided, and the 1983 amendments to SEPA a remedy to reverse the ambiguities caused by Downtown Traffic. "One well recognized indication of legislative intent to clarify, rather than change, existing law is doubt or ambiguity surrounding a statute.” Bowen v. Statewide City Employees Retirement Sys., 72 Wn.2d 397, 403, 433 P.2d 150 (1967) (citing 2 J.G. Sutherland, Statutes and Statutory Construction § 5110, at 526 (3d ed. 1943)).
The great weight of the legislative history of the 1983 SEPA amendments supports the proposition that the Legislature intended to modify SEPA to preclude case by case review of categorically exempt actions. While Downtown Traffic and Noel required case by case SEPA environmental review of proposals or approvals that were assertedly "major actions,” those cases were interpretations of a prior version of SEPA, where the categorical exemptions were mere guidelines, not administrative rules.
Downtown Traffic and Noel are no longer authoritative after the 1983 SEPA amendments and, accordingly, the claim of the concurrence/dissent that Noel, 98 Wn.2d at 380 n.2 is inconsistent with the majority approach is to no avail. Compare Concurrence/Dissent at 371-72. While the concurrence/dissent claims it is not "persuaded by the majority’s analysis, based on ambiguous legislative materials and two Court of Appeals opinions . . . .”, Concurrence/Dissent at 371, the concurrence/dissent does not address why the 1983 amendments to the statute [361]*361which postdated both Downtown Traffic and Noel are unpersuasive. We should recall that this statute refers to "[categories of governmental actions” and "types of actions” and further provides that "[a]n action that is categorically exempt under the rules adopted by the department may not be conditioned or denied under this chapter.” See, Concurrence/Dissent at 369.
The mills contend Snohomish involved court approval of an administrative categorical exemption that clearly allowed an individual major action (clear cutting), while Dioxin contends that the court disapproved an administrative exemption but upheld a statutory exemption. Sno-homish County v. State, 69 Wn. App. 655, 668-69, 850 P.2d 546 (1993), review denied, 123 Wn.2d 1003, 868 P.2d 871 (1994).
In Snohomish, we have exactly the same situation as in Noel v. Cole, 98 Wn.2d 375, 655 P.2d 245 (1982), except the opposite result. Snohomish, 69 Wn. App. at 666. The issue was: Are class-III forest practices insulated from SEPA review by categorical exemptions in WAC 197-11-800 (25)(a)? The Legislature had statutorily exempted class-III forest practices from SEPA without specifying what forest practices were in class III, leaving the definition of forest practices into various classes to Department of Natural Resources (DNR), as in Noel. DNR defined class III by administrative regulation to allow the harvesting of all marketable timber (clear cutting) on a 930-acre tract as categorically exempt. Snohomish County argued that this was a major action that could not be validly placed in class III as categorically exempt under Noel and Downtown Traffic. The court held:
DNR[’s] . . . argument stress[es] . . . the Legislature adopted amendments intended to allow DNR to rely on rules classifying forest practices without making a separate determination as to whether SEPA procedures must be followed. We are persuaded by DNR’s argument that the legislative amendments following Noel and Downtown Traffic render those cases no longer authoritative on this issue.
[362]*362Snohomish, 69 Wn. App. at 667.
SEPA and its amendments present a statutory scheme in which uniform rules are established to identify actions generally exempt from SEPA without the necessity of further review. To require DNR to fully apply SEPA to the process of classifying each forest practice application would render SE-PA’s categorical exemptions meaningless.
Snohomish, 69 Wn. App. at 668-69.
We find Snohomish on point, persuasive, and adopt its reasoning.
Concerned Citizens of Hosp. Dist. No. 304 v. Board of Comm’rs of Pub. Hosp. Dist. No. 304, 78 Wn. App. 333, 345 n.1, 897 P.2d 1267, review denied, 127 Wn.2d 1024, 904 P.2d 1157 (1995), also questioned Downtown Traffic and Noel:
These cases [Downtown Traffic and Noel] were decided under an earlier law and suggest that categorical exemptions may be denied in some cases on the basis of individual circumstances and critical judicial review. At least one recent case indicates that this approach is no longer appropriate.
Concerned Citizens, 78 Wn. App. at 345 n.l (citing Sno-homish, 69 Wn. App. at 666-69).
The Legislature’s 1995 amendment to SEPA forbidding the conditioning or denial of any action which is categorically exempt under SEPA rules further suggests the Legislature’s intention that specific proposals which are categorically exempt may not be blocked by case by case SEPA review:
An action that is categorically exempt under the rules adopted by the department may not be conditioned or denied under this chapter [SEPA].
RCW 43.21C.110(l)(a) (Supp. 1995) (amended by Laws op 1995, ch. 347, § 206). Clearly, the amendment confirms the Legislature’s intention that case by case review not be used to prevent approval of categorically exempt activities [363]*363as does the 1996 amendment which enacted the SEPA categorical exemption at issue in this case. Laws of 1996, ch. 322, § 1 (House Bill 2716).
In sum, the extensive legislative history of the 1983 amendments to SEPA, the only prior cases interpreting the 1983 amendments, Snohomish and Concerned Citizens, the 1995 amendments, and the recent statutory adoption of the NPDES permit exemption indicate that the Legislature did not intend RCW 43.21C.110(l)(a) to allow "as applied” challenges to, or case by case review of, categorically exempt activities. The entire purpose of the system of categorical exemptions is to avoid the high transaction costs and delays that would result from case by case review of categorically exempt types of actions that do not have a probable significant adverse environmental impact.
The concurrence/dissent also mistakenly relies upon Dioxin I to support its conclusion that regulatory categorical exemptions may be subject to as-applied challenges. Concurrence/Dissent at 371-72. To the contrary, Dioxin I merely recognized the appropriate forum vested with primary jurisdiction to hear Dioxin’s claim. There this court affirmed a previous superior court order dismissing a declaratory judgment action commenced by Dioxin holding that where the appellant does not challenge the rule itself but rather the application of the rule primary jurisdiction to consider issuance of specific permits is in the PCHB, not the superior court. Dioxin I, 119 Wn.2d at 771, held "appeal to the PCHB is the exclusive means for challenging issuance of permits.” As an alternative ground for dismissal, the supreme court also held that the doctrine of primary jurisdiction required such claims be brought initially before the PCHB. That is exactly what Dioxin did here. Dioxin I, 119 Wn.2d at 775.
Dioxin I lends no encouragement to the concurrence/ dissent’s mistaken claim that individual permits may be selectively challenged even though they fit squarely within a regulatory categorical exemption absent a claim that the categorical exemption is itself invalid.
[364]*364The bottom-line of the concurrence/dissent is that "administrative categorical exemptions can be challenged on an 'as applied’ or case specific basis.” Concurrence/ Dissent at 370-71. For reasons previously stated this conclusion is neither consistent with the 1983 amendments to the statute, the legislative history, nor the post-1983 case law.
Beyond that, the concurrence/dissent attempts to justify its conclusion by claiming it is also based on "common sense,” by claiming "this analysis allows Ecology and businesses to rely on administrative categorical exemptions in not requiring threshold determinations of significance or EISs .... [and] results in . . . administrative efficiency and cost-effectiveness . . . .” Concurrence/ Dissent at 371.
Nothing, however, could be further from the truth. Any regulatory categorical exemption under the analysis of the concurrence/dissent would always be potentially subject to the claim of any individual who characterized the action as "major,” notwithstanding that it clearly fell within a valid categorical exemption. Such would mean that neither the government nor permit applicant could rely on the categorical exemption. Both would always face the risk of litigation over whether or not the particular proposal was indeed a "major action” and thus subject to full SEPA review even though the action was admittedly within an exempt category.
Such is neither efficient nor cost-effective—which, after all, is the purpose for categorical exemptions in the first place.
By the concurrence/dissent’s view, it is not only reasonably possible but a virtual certainty, that construction of even a single family residence, while firmly within a categorical exemption, could nevertheless be challenged as an alleged "major action” notwithstanding the exemption. If such was the legislative intent, the Legislature certainly didn’t say so.
[365]*365CONCLUSION
We hold the 1983 SEPA amendments authorized the Department of Ecology to promulgate administrative rules categorically exempting from SEPA review "types of actions” which do not significantly affect the environment. The courts may still decide if the categorical exemption contained in the rules meets this criterion. The courts may also decide whether a specific proposed action actually fits within the particular categorical exemption. We reverse the superior court as a matter of law, uphold and enforce the regulatory exemption, and award appellants their costs on appeal.
Durham, C.J., and Dolliver, Madsen, and Alexander, JJ., concur.