OPINION ANNOUNCING THE JUDGMENT OF THE COURT
HUTCHINSON, Justice.The Commonwealth directly appeals a Westmoreland County Common Pleas’ order dismissing several criminal charges filed against appellee. He was charged with violating Section 610(7) of the Solid Waste Management Act, Act of July 7, 1980, P.L. 380, No. 97, 35 P.S. §§ 6018.101-6018.-1003 (Supp.1985) (“Act”), 35 P.S. § 6018.610(7), obstructing *195a Department employee,1 and with obstruction of justice under 18 Pa.C.S. § 5101.
In a pre-trial motion, appellee challenged the validity of the charges on constitutional grounds. He claimed that the warrantless search provisions of the Act were unconstitutional.2 Common Pleas agreed and dismissed those charges because it believed appellee was entitled to prevent an unconstitutional search.3 The Commonwealth appealed to Commonwealth Court. That court transferred the case to us pursuant to 42 Pa.C.S. § 5103(a) because we have exclusive jurisdiction of cases where a court of common pleas has ruled a state statute unconstitutional. 42 Pa.C.S. § 722(7).
On analysis of the statute and relevant case law, we conclude that the warrantless inspection provisions of the Act, in the current absence of a regulation defining the circumstances under which such inspections of non-hazardous waste will be conducted, violates the Fourth Amendment of the United States Constitution. We also believe that the “open fields” doctrine, developed under the Fourth Amendment, does not apply in this case. The lands here were used for commercial activities which, because of a strong public interest, requires extensive and pervasive regulation and the attempted search involved an actual physical intrusion. See Dow Chemical Co. v. United States, — U.S. —, 106 S.Ct. 1819, 90 L.Ed.2d 226 (1986). The order of Common Pleas is affirmed.
*196Appellee has had a history of dealings with the Department. In early 1982, he was in the process of attempting to renew several expired permits to store sewage on his property.4
In January of that year, appellee took some oily waste from a spill site in Westmoreland County. In that same month, the Department attempted to search his property to determine whether that material had been illegally dumped on it. Appellee refused to admit them. The Department then contacted appellee’s attorney to arrange a consensual search of the property. It was agreed that the Department’s agents would identify themselves to the Lutz family before actually searching the property. Appellee’s attorney testified at the hearing in this case that he believed that this procedure would be followed whenever the Department wished to search his client’s property. The Department’s attorney stated that the procedure was intended only for the search in January. The Department did in fact follow the procedure at that time.
On April 22, 1982, two Department agents attempted to conduct a search of appellee’s property without either obtaining a search warrant or attempting to contact appellee before conducting the search. The agents had been told by an anonymous informant that solid waste was on appellee’s property. Appellee refused to allow the agents to carry out their search, confiscated a camera and empty sample bottles and ordered the agents off his property. The agents com*197plied with his request. After obtaining his permission, the Department was able to conduct its search the next day. However, the Department filed the charges that are before us based on appellee’s initial refusal to allow a search and the seizure of its camera and supplies.
The Department, as appellant, claims that the Solid Waste Management Act allows it to conduct warrantless searches for all solid wastes. Section 608 of the Act provides:
§ 6018.608. Production of materials; recordkeeping requirements; rights of entry
The department and its agents and employees shall:
(1) Have access to, and require the production of, books and papers, documents, and physical evidence pertinent to any matter under investigation.
(2) Require any person or municipality engaged in the storage, transportation, processing, treatment or disposal of any solid waste to establish and maintain such records and make such reports and furnish such information as the department may prescribe.
(3) Enter any building, property, premises or place where solid waste is generated, stored, processed, treated or disposed of for the purposes of making such investigation or inspection as may be necessary to ascertain the compliance or noncompliance by any person or municipality with the provisions of this act and the rules or regulations promulgated hereunder. In connection with such inspection or investigation, samples may be taken of any solid, semisolid, liquid or contained gaseous material for analysis....
35 P.S. § 6018.608 (Supp.1985). Appellee first argues that this section does not authorize the Department to conduct warrantless searches. We disagree. We conclude that the Act, read as a whole, does authorize such conduct.
The stated legislative policy of the Act is to “provide a flexible and effective means to implement and enforce the provisions of this act.” Section 102(5), 35 P.S. § 6018.102(5) *198(Supp.1985). The Department is given authority to “do any and all other acts and things not inconsistent with any provisions of this act, which it may deem necessary or proper for the effective enforcement of this act....” Section 104(13), 35 P.S. § 6018.104(13) (Supp.1985). Thus, it is designed to give the broadest possible powers to the Department to control waste management in this Commonwealth.
Section 608, quoted above, empowers the Department to have materials produced and records kept and affords it a right of entry5 where solid waste is generated or otherwise managed. This section provides that the Department shall enter such facilities. Shall is ordinarily construed as an imperative. Commonwealth v. Garland, 393 Pa. 45, 142 A.2d 14 (1958). Thus, while Section 608 is silent on the question of a warrant, we believe that it was the intent of the legislature to authorize warrantless searches pursuant to Section 608(3).6
Furthermore, Section 610, which proscribes certain conduct, provides in pertinent part:
It shall be unlawful for any person or municipality to:
(7) Refuse, hinder, obstruct, delay, or threaten any agent or employee of the department in the course of performance of any duty under this act, including, but not limited to, entry and inspection under any circumstances.
35 P.S. § 6018.610(7) (Supp.1985).7 This existence of criminal, as opposed to civil, penalties underscores the intention *199of the legislature to permit warrantless searches by the Department in enforcing the Act’s provisions.
Against this construction appellee argues that the Act provides a procedure whereby the Department may obtain a search warrant. Section 609, 35 P.S. § 6018.609 (Supp.1985). That section permits the Department to obtain a search warrant on three grounds: the search is part of a general administrative plan to determine compliance with the Act; there is reason to believe there is a violation of the Act; or the Department has been refused entry to the site in question. Id. These grounds meet the lesser standard of probable cause allowed for administrative search warrants. See Camara v. Municipal Court, 387 U.S. 523, 87 S.Ct. 1727, 18 L.Ed.2d 930 (1967).
Thus, the Department may obtain a warrant if it anticipates a landowner’s refusal of a warrantless search. It also has the authority to obtain a warrant, without a full court hearing, after such a refusal. Section 609 gives the Department the flexibility it needs without requiring the issuance of a warrant in all cases. Nonetheless, although the Act authorizes warrantless searches by the Department, mere statutory authorization of this conduct is not enough. Any such search is still subject to constitutional limitations.
The United States Supreme Court has analyzed the constitutionality of similar statutes allowing administrative searches of commercial operations under the federal constitution. In 1967, that Court determined that Fourth Amendment protections do indeed apply to commercial property. See v. City of Seattle, 387 U.S. 541, 87 S.Ct. 1737, 18 L.Ed.2d 943 (1967); Camara v. Municipal Court, supra. On several occasions it has held that certain warrantless administrative searches without probable cause may be constitutional:
The greater latitude to conduct warrantless inspections of commercial property reflects the fact that the expectation of privacy that the owner of commercial property enjoys in such property differs significantly from the sanctity accorded an individual’s home, and that this privacy inter*200est may, in certain circumstances, be adequately protected by regulatory schemes authorizing warrantless inspections.
Donovan v. Dewey, 452 U.S, 594, 598-99, 101 S.Ct. 2534, 2537-38, 69 L.Ed.2d 262 (1981). The Court summarized the cases on this issue by stating:
These decisions make clear that a warrant may not be constitutionally required when Congress has reasonably determined that warrantless searches are necessary to further a regulatory scheme and the federal regulatory presence is sufficiently comprehensive and defined that the owner of commercial property cannot help but be aware that his property will be subject to periodic inspections undertaken for specific purposes.
Id. at 600, 101 S.Ct. at 2539. By this analysis, the Court in Dewey upheld a warrantless inspection under the Mine Safety and Health Act of 1977, 30 U.S.C. §§ 801-962. In doing so, the Court seemingly relied on the pervasive regulation of mining, the regularity of the inspections and the strong federal interest in protecting persons employed in the mining industry.
In Colonnade Catering Corp. v. United States, 397 U.S. 72, 90 S.Ct. 774, 25 L.Ed.2d 60 (1970), the Court also held that, because of its history of pervasive regulation, the alcoholic beverage industry was subject to warrantless searches to promote federal interests in the control of the sale of alcohol. Likewise, in United States v. Biswell, 406 U.S. 311, 92 S.Ct. 1593, 32 L.Ed.2d 87 (1972), the Court held that warrantless searches under the Gun Control Act of 1968, 18 U.S.C. §§ 921-929, were justified because there was a comprehensive inspection scheme, a strong federal interest in gun control, and only a limited threat to the privacy of the gun dealer.
However, in Marshall v. Barlow’s, Inc., 436 U.S. 307, 98 S.Ct. 1816, 56 L.Ed.2d 305 (1978), the Court invalidated a warrantless inspection under Section 8(a) of the Occupational Safety and Health Act, 29 U.S.C. § 657(a). Because the OSHA provisions covered all businesses engaged in inter*201state commerce and there were no standards governing the searches, the Court held that there was no reasonable expectation that the property would actually be subjected to warrantless searches.
In each of these cases, the United States Supreme Court balanced the need for warrantless regulatory searches against the business owner’s expectation of privacy. In so doing, it looked at four factors: first, whether the business operator is on notice that he is engaged in activity which may subject him to warrantless searches; second, whether the regulation of the industry is pervasive and regular, considering the history of the regulatory scheme as a factor in this determination; third, whether there is a strong governmental interest in the search; and fourth, whether there are reasonable legislative or administrative standards governing the search.8
We believe that the fourth requirement is not satisfied on the record before us. The Dewey Court, in analyzing the provisions of the Mine Safety and Health Act, noted that it provided inspections at least four times per year for underground mining, and at least twice a year for surface mining operations. The Solid Waste Management Act does not set up any specific schedule of inspections. The Department is merely given the power to conduct inspections at any reasonable time. Thus, there is no legislative determi*202nation of either the frequency of searches on commercial property used to store solid waste or the circumstances which will result in a warrantless search. It appears that the legislature has left such definition to the Department, the regulatory agency. Section 104(7), 35 P.S. § 6018.-104(7).
However, the Department has failed to properly and publicly set forth any further definition. The regulations adopted by the Department and published in the Pennsylvania Code, 25 Pa. Code § 75.1-75.450, do not provide any sort of timetable or schedule of regular inspections. There is no evidence of record to indicate that the particular search in this case was in fact part of a regular inspection nor any public declaration by the Department of the administrative standards which will trigger an ad hoc inspection.9
The trial court in the case before us held that Dewey, supra, required legislative or administrative periodicity for searches in all cases. We do not believe this is an accurate reading of Dewey.10 In Colonnade Catering, supra, Congress gave extremely broad powers to the Treasury Department to conduct searches for liquor violations. The United *203States Supreme Court held that the statute’s prohibition of forcible entry sufficiently limited this broad power and saved the warrantless search, despite the presence of civil penalties for refusal to allow it, because of the long history of close supervision of the liquor industry. Our Act similarly prohibits forceful entry and has both civil and criminal penalties for refusing to allow inspection, § 610(7). Refusal itself provides grounds for issuing a warrant, § 609(3).
In industries where the governmental interest is special, either because of a long history of pervasive regulation, as in the case of alcohol, Colonnade Catering, or firearms, Biswell, or because of the nature of the risks involved, as in the nuclear power industry, see Dewey, supra, 452 U.S. at 606, 101 S.Ct. at 2542 (quoted below), warrantless searches with minimal restrictions are permitted because operators who engage in such businesses are on notice that they will be subject to them. Thus, the operators’ expectation of privacy is reduced and such searches are constitutional because they must reasonably be expected by the persons in those businesses.
Hazardous waste poses severe public health risks not only to those working in the industry but to the public at large. It is the type of business that can be reasonably subjected to warrantless searches with minimal definition. This is so, even though the special dangers of hazardous waste and its consequent separation from other solid waste for special regulatory treatment is recent. As the Court said in Dewey:
Under [the view that there must be a longstanding regulatory scheme in all cases], new or emerging industries, including ones such as the nuclear power industry that pose enormous potential safety and health problems could never be subject to warrantless searches even under the most carefully structured inspection program simply because of the recent vintage of regulation.
452 U.S. at 606, 101 S.Ct. at 2542. By definition, the interests of the public at large must predominate when hazardous waste is involved. Our statute categorizes as *204hazardous that waste which because of its quantity, concentration, or physical, chemical, or infectious characteristics may:
(1) cause or significantly contribute to an increase in mortality or an increase in morbidity in either an individual or the total population; or
(2) pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, disposed of or otherwise managed.
Section 103, 35 P.S. § 6018.103. The risks these substances pose to the public, coupled with the commercial operator’s knowledge of those risks, justify warrantless searches of sites where they are kept. The nature of the business and its narrow definition justify the search as indicated when Dewey is compared to Barlow’s. In short, we conclude that such searches are a reasonable means of ameliorating the great risk these materials pose to the general public.
We do not believe the same is true with respect to non-hazardous solid waste, the material involved in this case. The Act covers all waste, including municipal, residual or hazardous wastes. It specifically defines agricultural waste, food processing waste, hazardous waste (discussed, supra), municipal waste, and residual waste. While we recognize an important public interest in controlling nonhazardous waste, it does not rise to the same level of concern as hazardous waste. Although certainly unpleasant at times, ordinary solid waste does not pose the same danger to public health as hazardous waste. Since the public interest is less vitally affected and the industry itself has fewer of the special characteristics that would put an operator on notice of random regulatory searches, we believe that warrantless searches for ordinary solid waste cannot withstand constitutional scrutiny absent proper adoption by the Department of a flexible inspection schedule or a reasonable definition of the circumstances under *205which such searches will be conducted. See Dewey, supra.11
Alternately, the Department argues that the search should be upheld under the “open fields” exception to the Fourth Amendment.12 That exception, first set out by the United States Supreme Court in Hester v. United States, 265 U.S. 57, 44 S.Ct. 445, 68 L.Ed. 898 (1924), and recently reaffirmed in Oliver v. United States, 466 U.S. 170, 104 S.Ct. 1735, 80 L.Ed.2d 214 (1984), states that there can be no reasonable expectation of privacy in areas beyond the traditional curtilage surrounding one’s home.
The United States Supreme Court has just addressed a question similar to that presented here: the applicability of the open fields doctrine to outdoor commercial property. In Dow Chemical Co. v. United States, — U.S. —, 106 S.Ct. 1819, 90 L.Ed.2d 226 (1986), the Court analyzed whether the Environmental Protection Agency could lawfully take aerial photographs of Dow’s chemical processing plant. That plant, because of the size of its facility and the dangers of conducting the activity in closed spaces, left much of its equipment exposed to the elements. The plant was subject to extremely stringent security precautions to protect its trade secrets.
The Court held that taking aerial photographs of the plant did not violate the Fourth Amendment because the pictures were of items that could ordinarily be seen in the air. The Court did note the limited nature of its holding:
Admittedly, Dow’s enclosed plant complex, like the area in Oliver, does not fall precisely within the “open fields” doctrine. The area at issue here can perhaps be seen as falling somewhere between “open fields” and curtilage, but lacking some of the critical characteristics of both. *206Dow’s inner manufacturing areas are elaborately secured to ensure they are not open or exposed to the public from the ground. Any actual physical entry by EPA into any enclosed area would raise significantly different questions, because “[t]he businessman, like the occupant of a residence, has a constitutional right to go about his business free from unreasonable official entries upon his private commercial property.” See v. City of Seattle, supra [387 U.S. 541], at 543 [87 S.Ct. at 1739]. The narrow issue raised by Dow’s claim of search and seizure, however, concerns aerial observation of a 2,000-acre outdoor manufacturing facility without physical entry.
106 S.Ct. at 1825-26 (footnotes omitted). The Court also noted, in limiting the application of this case, that it was not addressing any question of general “business curtilage.” 106 S.Ct. at 1827 n. 7.
We believe that the case before us is distinguishable from Dow. The Department attempted actual entry onto private land that was not visible from any public area. Dow’s holding is expressly limited to aerial searches. The implication of the above-quoted language is that physical entry into the enclosed plant complex, even the outdoor portions of that area, would not be permissible because that area is not an open field.
The conclusion that outdoor business areas are not open fields is consistent with the purpose of the open fields doctrine. The basic premise of the open fields doctrine, that there can be no reasonable expectation of privacy in an open field, is at times incompatible with the idea that a business owner has a reasonable expectation of privacy in his property. This is especially true where the business must, by its nature, be conducted outside. See, e.g., United States v. Swart, 679 F.2d 698 (7th Cir.1982) (used car dealer’s parking lot was part of the “business curtilage” and was not subject to warrantless search after business hours); Allinder v. Ohio, 614 F.Supp. 282 (N.D. Ohio .1985), appeal pending, No. 85-3664 (6th Cir.) (open fields doctrine cannot *207apply to warrantless administrative searches of beekeeping facility).
Thus, because the Court in Oliver, supra, required a balancing of governmental intrusion against the societal values protected by the Fourth Amendment, 104 S.Ct. at 1743, we believe that in this case the legitimate expectation of privacy, protected by the provisions of the Act and the decisions of the United States Supreme Court discussed in the first portion of this opinion, renders the open fields doctrine inapplicable to this property. The Department cannot rely on it to justify its search of appellee’s property. Because we can find no constitutional exception to the requirement of a warrant in this case, we would affirm the dismissal of the charges.
The order of the Court of Common Pleas of Westmoreland County is affirmed.
FLAHERTY, J., joins in the opinion announcing the judgment of the Court and files a concurring opinion. NIX, J., files a concurring opinion. LARSEN, J., files a dissenting opinion in which McDERMOTT and PAPADAKOS, JJ., join.. Appellee was also charged with violating Section 610(1) of the Act, 35 P.S. § 6018.610(1), dumping solid waste without a permit. That charge is not before us.
. The Department claims that the constitutionality of the statute allowing entry for inspection was not challenged and therefore is waived. Although appellee’s pre-trial motion only raised general constitutional violations, it is clear on this record that the Department relied solely on the statutory right of entry and that it knew of the grounds for appellee’s contention. Indeed, the Department’s response to the motion specifically cited the statute as authority for its action. Thus, it cannot claim the issue was waived.
. The Department did not file any charges based on appellee's use of force in preventing the search.
. Appellee argues that because he is not licensed to store solid waste under this Act he is not subject to the inspection provisions, and therefore all searches must be based on warrants issued on probable cause. We believe that this argument fails. Although the United States Supreme Court at one time stated that entry into a regulated business supported the warrantless searches on an implied consent theory, United States v. Biswell, 406 U.S. 311, 316, 92 S.Ct. 1593, 1596, 32 L.Ed.2d 87 (1972), it has since stated that the existence and pervasive nature of the regulations, not consent, give the notice required. Donovan v. Dewey, 452 U.S. 594, 603, 101 S.Ct. 2534, 2540, 69 L.Ed.2d 262 (1981). See W. LaFave, Search and Seizure, § 10.2, n. 52.3 (Supp.1986). On the facts of this case, this argument would not succeed in any event. Appellee stated that he was attempting to obtain a permit under the Act. Thus, he cannot claim that he was unaware of the Act’s provisions.
. Clear designation of the Department’s power as a "right of entry” is stated in the title of Section 608. This title may be used to aid in statutory construction. 1 Pa.C.S. § 1924.
. Several federal statutes have similar language on the right of entry. See, e.g., Internal Revenue Code, 26 U.S.C. § 5146; Gun Control Act, 18 U.S.C. § 923(g); Occupational Safety and Health Act, 29 U.S.C. § 657. This language has been held to authorize warrantless searches. See Colonnade Catering v. United States, 397 U.S. 72, 90 S.Ct. 774, 25 L.Ed.2d 60 (1970); Biswell, supra; Marshall v. Barlow’s, Inc., 436 U.S. 307, 98 S.Ct. 1816, 56 L.Ed.2d 305 (1978). These cases are discussed at 343.
. Appellee was cited for violation of this section.
. The record shows that the Solid Waste Management Act meets the first three requirements. It contains specific definitions of what is and what is not subject to its provisions. See Section 103, 35 P.S. § 6018.103; see also 25 Pa.Code §§ 75.1-75.450. The second is also satisfied. The regulation of the industry is pervasive, with tight restrictions on the handling of solid and hazardous waste. The potential health hazards of improper waste management provide the strong governmental interest that is also needed to justify a warrant-less inspection scheme. The Act contains the following finding in its declaration of policy:
[I]mproper and inadequate solid waste practices create public health hazards, environmental pollution, and economic loss, and cause irreparable harm to the public health, safety and welfare....
Section 102, 35 P.S. § 6018.102. In addition, Article I, Section 27 of the Pennsylvania Constitution provides that there is a right to clean air and pure water, thus giving constitutional implications to environmental protection measures.
. In its brief, the Department states that its policy is to inspect monthly. It also cites federal authority to show that policy can be considered in this analysis. See United States v. Kaiyo Maru No. 53, 699 F.2d 989 (9th Cir.1983). We cannot consider this policy, however, since it was never introduced at the, hearing on appellee’s pre-trial motion and has not been placed on the record anywhere beyond its mention in the Department’s brief. See also Section 1208 of the Act of July 31, 1968, P.L. 769, No. 240, 45 P.S. § 1208.
. The Dewey Court’s emphasis on the congressional requirement that mine inspections take place at regular intervals was noted in the process of distinguishing that case from Marshall v. Barlow’s, Inc., supra. In Barlow’s, the Court invalidated OSHA warrantless searches because the OSHA statute allowed searches of all worksites engaged in interstate commerce. This did not provide reasonable notice to previously unregulated workplaces that such searches would be conducted. The Dewey Court, also considering legislation designed to protect on-site employees, upheld warrantless searches under a statute which set a regular schedule for them. It seems to us the congressionally-defined schedule, coupled with the narrower scope of the regulations, were crucial factors in distinguishing Barlow’s prohibition on warrantless searches under OSHA and upholding the constitutionality of such searches under the Mine Health and Safety Act.
. We note that the Act contains a severability clause. Section 1002, 35 P.S. § 6018.1002. The distinction between hazardous waste and other forms of solid waste is a distinction already present in the Act. There is a separate article dealing with hazardous waste, and Section 606 contains separate criminal penalties for those violating the hazardous waste portions of the Act.
. Appellee did not attack the search in this case under Article I, Section 8 of the Pennsylvania Constitution.