dissenting.
As I view the majority’s reliance upon custom and usage in construing the scope of the pollution exclusion to be inconsistent with the analysis in Madison Constr. Co. v. Harleysville Mut. Ins. Co., 557 Pa. 595, 735 A.2d 100 (1999), I respectfully dissent. The words of an insurance policy are to be interpreted in their natural, plain, and ordinary sense, and only if the policy language is ambiguous is resort to be made to extrinsic evidence. See Madison, 557 Pa. at 608-09, 735 A.2d at 108. While certainly reference to trade usage is available to explain material terms of certain specialized contracts, it should not be utilized to create a variance from the agreement. See generally 21A Am.Jur.2d Customs and Usages § 25 (1998)(stating that “parol or extrinsic evidence of a usage or custom is not admissible where the intent and meaning of the parties as expressed in a contract are clear and unambiguous, especially where the purpose of the evidence is to contradict, vary, modify, qualify, or override the plain, unambiguous terms”). Moreover, I disagree that the form of custom and usage alleged is a relevant consideration in the present context, involving, not specialized terms of a document negotiated between participants in some particular trade or industry, but the standard terms of a comprehensive general liability policy offered to a widely diverse business public. Rather, I agree with the en banc decision of the Superior Court, which con-*506eluded that the terms “sudden and accidental” should be interpreted according to their ordinary usage, should be viewed as clear and unambiguous, and should be deemed to include a temporal element connoting an event that is abrupt and lasting only a short time. See Sunbeam Corp. v. Liberty Mut. Ins. Co., 740 A.2d 1179, 1186-88 (Pa.Super.1999) (en banc). Cf. Madison, 557 Pa. at 608-10, 735 A.2d at 108-09 (construing the terms “discharge, dispersal, seepage, migration, release or escape” in the absolute pollution exclusion clause according to ordinary usage).
In addition, although I am troubled by the representations alleged to have been made by the insurance industry to the Insurance Commissioner concerning the modification of the language of the pollution exclusion, I do not agree that a claim predicated on such assertions should proceed at the behest of an insured on a theory of regulatory estoppel, at least in the circumstances presented. Significantly, as aptly noted by the trial court (the Honorable R. Stanton Wettick, Jr.), the representations alleged would have occurred thirty years ago, and the Insurance Department did not alter its regulations and approval practices after it obviously must have become aware of the interpretation that the insurance industry subsequently accorded to the “sudden and accidental” clause, nor has it sought to intervene on behalf of Appellants herein. I would also note that such an application of the regulatory estoppel theory has not been previously recognized by the appellate courts of this Commonwealth; indeed, most other jurisdictions have rejected arguments in this context based upon regulatory estoppel. See generally SnyderGeneral Corp. v. Great American Ins. Co., 928 F.Supp. 674, 682 (N.D.Tex.1996) (collecting cases).1 Finally, in my view, the allegations of the complaint provide a tenuous basis to support an inquiry into the internal decision making of a coordinate branch of government, partic*507ularly in light of the separation of powers concerns implicated in doing so.
Justice CASTILLE joins this dissenting opinion.. With respect to the majority’s allusion to the theory of judicial estoppel, such theory was not advanced by the appellants as a ground for relief in their complaint, and the pertinent representations of the insurance industry are not alleged to have been made in an adjudicative context.