delivered the opinion of the court:
Petitioner, Waste Management of Illinois, Inc. (Waste Management), sought local site approval from the Village of Bensenville (Village) for construction of a solid waste transfer station pursuant to section 39.2 of the Environmental Protection Act (Act) (Ill. Rev. Stat. 1987, ch. lllVa, par. 1039.2). Following an evidentiary hearing, the Village denied the request for site approval, and Waste Management appealed the Village’s decision to the Illinois Pollution Control Board (PCB). Ill. Rev. Stat. 1987, ch. IIIV2, par. 1040.1.
On review, the PCB upheld the Village’s denial of site approval for the waste transfer station. Following the PCB’s denial of its motion to reconsider, Waste Management filed its petition for review with this court. Ill. Rev. Stat. 1987, ch. III1/2, par. 1041.
The record reveals that on July 22, 1988, Waste Management filed with the Village a proposal for construction of a solid waste transfer station on approximately seven acres of property located immediately east of Waste Management’s Garden City disposal plant, a waste hauling company, in the Village of Bensenville. The transfer station was designed to receive, compact, and transfer to sanitary landfills nonhazardous and nonspecial refuse. Its purpose was to make waste hauling in the service area more efficient and cost effective. The facility was also to be used as a processing center for recycling aluminum, paper, glass, wood skids, and cardboard. The transfer station operations, including unloading, compacting, and loading were to be completely enclosed, minimizing or eliminating noise, odors, dirt, and litter.
On November 10, 1988, the Village held a hearing on the proposal for the waste transfer station. In addition to the members of the village board, counsel for Waste Management and for the Village were present. At the hearing, Waste Management presented seven witnesses who testified in support of the application. No testimony or other evidence was presented in opposition to the proposal.
The evidence offered by Waste Management to establish the necessity for the waste transfer station consisted of the testimony of Edward Evenhouse, general manager of the Garden City disposal plant (Garden City). Evenhouse testified that the waste transfer station was necessary due to three factors: (1) the scarcity of available landfill space in the vicinity of the service area; (2) the imposition of a quota system by the nearest available landfill; and (3) the then-present inefficiencies of transporting waste from the service area to existing disposal sites.
On cross-examination Evenhouse stated that Garden City did not service all of the waste needs in the area, but he was unable to testify as to the percentage of waste Garden City did handle within the service area. He also acknowledged that the application for site location approval did not include an economic analysis of the proposal.
Evenhouse testified further that the waste collected by Garden City was taken to various landfills and waste transfer stations including those located at Hooker Street in Chicago, Lake landfill in North-brook, the Groot transfer station, Congress Development landfill, Mallard Lake, and Woodland and Settlers Hills. Evenhouse was unable to testify as to the amount of waste that was being transported to the Lake landfill, but acknowledged that Lake landfill had obtained a three-year extension of its operations. He could not state the projected life of the Congress Development landfill, and although he testified that this facility had imposed quotas limiting the amount of waste it would accept from Garden City, Evenhouse did not know the maximum number of loads it would accept. He also stated that his information regarding the projected closing of the Mallard Lake landfill in 1993 was derived from newspaper articles and that the Mallard Lake landfill had never refused to accept waste from Garden City.
Evenhouse also testified that the Mallard Lake landfill was about eight miles from Garden City and that the Congress Development facility was about four miles away. Evenhouse indicated that these were reasonable distances to drive a collection truck to unload. He testified that he hoped the construction of the transfer station would improve the efficiency of Garden City’s operations by allowing for the elimination of some of its collection trucks, and he stressed the importance of recycling waste. Evenhouse stated that the proposed transfer station was designed to accommodate a maximum of 12 loads per day, but acknowledged that the application for site approval did not limit Garden City to 12 loads per day. He also indicated that Garden City could initiate recycling operations on this site without obtaining approval from the Village.
On February 2, 1989, the Village denied the application for site approval, finding that Waste Management had not established that the waste transfer station was necessary or that the impact on existing traffic flow would be minimal. (Ill. Rev. Stat. 1987, ch. 1111/2, pars. 1039.2(a)(i), (a)(vi).) On February 8, 1989, Waste Management filed its petition for review with the PCB. (Ill. Rev. Stat. 1987, ch. 1111/2, par. 1040.1(a).) On June 21, 1989, at the PCB’s request, Waste Management waived the statutory deadline of June 22, 1989, and agreed to a continued decision date of June 29, 1989. On June 27, 1989, Waste Management, at the request of the PCB, again waived the statutory deadline and the decision date was continued to July 13, 1989.
On July 13, 1989, the PCB issued an order affirming the denial by the Village of the application for local site approval for the waste transfer station. The order did not set forth the reasons for the PCB’s decision, but stated that an opinion in support of the order would be issued on August 10, 1989. The July 13, 1989, order also provided that the time period within which the PCB would entertain any motions for reconsideration would commence with the issuance of its August 10, 1989, opinion.
In the opinion issued August 10, 1989, the PCB upheld the Village’s determination on the question of the necessity of the waste transfer station, but found that the Village’s decision regarding traffic flow was against the manifest weight of the evidence. The PCB affirmed the Village’s denial of site approval on the basis that Waste Management had not established that the transfer station was necessary to accommodate the waste needs of the area it was intended to serve.
Waste Management filed a motion for reconsideration with the PCB, asserting that the PCB had not taken final action within 120 days as required by statute (Ill. Rev. Stat. 1987, ch. 1111/2, par. 1040.1) and that the PCB had erred in affirming the Village’s determination regarding the necessity of the transfer station (Ill. Rev. Stat. 1987, ch. 1111/2, par. 1039.2(a)(i)). Upon the denial of its motion for reconsideration, Waste Management filed the instant petition for review with this court.
We initially consider whether Waste Management’s application for site location of the waste transfer station should be deemed approved due to the failure of the PCB to issue its opinion within 120 days.
In this case, the PCB was required to take final action on Waste Management’s petition by July 13, 1989, in compliance with section 40.1 of the Act (Ill. Rev. Stat. 1987, ch. HV-k, par. 1040.1). Waste Management contends that the July 13, 1989, order did not constitute final action and, consequently, its application should be deemed approved by operation of law. The Village and the PCB assert that although the order of July 13, 1989, did not contain the explanation of the decision, it was a final determination affirming the Village’s denial of site location approval. We find this argument unpersuasive.
Section 40.1(a) of the Act outlines the procedure for appeal to the PCB from a denial of local site approval and provides that if there is no final action by the PCB within 120 days, the petitioner may deem the site location approved. (Ill. Rev. Stat. 1987, ch. HV-k, par. 1040.1(a).) Section 33(a) of the Act requires the PCB to file and publish a written opinion stating the facts and reasons leading to its decision. (Ill. Rev. Stat. 1987, ch. HV-k, par. 1033(a); Wells Manufacturing Co. v. Pollution Control Board (1978), 73 Ill. 2d 226, 233-34, 383 N.E.2d 148, 151; Mystik Tape v. Pollution Control Board (1975), 60 Ill. 2d 330, 336, 328 N.E.2d 5, 8; Clean Air Coordinating Committee v. Environmental Protection Agency (1976), 42 Ill. App. 3d 124, 128, 355 N.E.2d 573, 576.) We believe that these two sections of the Act must be considered together when determining the deadline for final action by the PCB. (See generally Clean Air Coordinating Committee, 42 Ill. App. 3d at 127, 335 N.E.2d at 576; Waste Management of Illinois, Inc. v. Pollution Control Board (1988), 175 Ill. App. 3d 1023, 1035, 530 N.E.2d 682, 692.) When read together, these two sections indicated that the PCB must issue its final determination within 120 days and that the final determination must include the reasons leading to its decision.
An administrative order is final if the process of administrative decision making has reached a stage where judicial review will not disrupt the orderly process of adjudication, and the rights and obligations of the parties have been determined, or legal consequences will flow from the agency action. Port of Boston Marine Terminal Association v. Rederiaktiebolaget Transatlantic (1970), 400 U.S. 62, 71, 27 L. Ed. 2d 203, 210, 91 S. Ct. 203, 209; McHenry County Landfill, Inc. v. Environmental Protection Agency (1987), 154 Ill. App. 3d 89, 98, 506 N.E.2d 372, 378.
The requirement that the PCB set forth the reasons leading to its decision is essential because it provides this court with the information necessary for a complete and fair review of the administrative decision by the PCB, and without such information, a thorough and judicious review of the decision cannot be made. Wells Manufacturing Co., 73 Ill. 2d at 234, 383 N.E.2d at 151; Mystik Tape, 60 Ill. 2d at 336, 328 N.E.2d at 8; Clean Air Coordinating Committee, 42 Ill. App. 3d at 128, 355 N.E.2d at 576; Allied Metal Co. v. Pollution Control Board (1974), 22 Ill. App. 3d 823, 833, 318 N.E.2d 257, 264.
The July 13, 1989, order in the case at bar cannot be considered a final determination of the proceedings before the PCB because it merely affirmed the Village’s denial of the site location without setting out the facts and reasons justifying the decision. The August 10, 1989, opinion recited the evidence and reasons to support the earlier decision and must be held to be a material and substantive modification of the PCB’s earlier decision. (Clean Air Coordinating Committee, 42 Ill. App. 3d at 128, 355 N.E.2d at 576.) Prior to the issuance of the August 10, 1989, opinion, neither party could speculate as to the basis for the PCB’s affirmance of the permit denial, and this court would not have had the information necessary for a complete and fair review of the ultimate and final decision of the PCB. Clean Air Coordinating Committee, 42 Ill. App. 3d at 128, 355 N.E.2d at 577.
Moreover, the actions of the PCB indicate that it perceived the August 10, 1989, opinion to be the final action disposing of Waste Management’s application. The rules of the PCB provide that a party may bring a motion for reconsideration of a final order within 35 days. (35 Ill. Adm. Code §103.240 (1985).) The July 13, 1989, order specifically stated that motions for reconsideration would not be entertained until after the issuance of the August 10, 1989, opinion. This provision in the July 13, 1989, order indicates that the PCB was aware that further action was required and determined that it would entertain motions for reconsideration only upon the entry of a final order which ultimately disposed of the site location application.
In addition, the PCB did not reject as untimely the motion for reconsideration filed by Waste Management on August 25, 1989. A party challenging an administrative order must file a motion for reconsideration or a petition for review by the appellate court within 35 days. (35 Ill. Adm. Code §103.240 (1985); Ill. Rev. Stat. 1987, ch. IIIV2, par. 1041(a).) In the instant case, if the July 13, 1989, order constituted the final action by the PCB, a motion for reconsideration or a petition for review by this court would have been due on or before August 17, 1989. If the August 10, 1989, opinion constituted the final action by the PCB, a motion for reconsideration or a petition for review by this court would have been due on or before September 14, 1989. Although Waste Management did not file its motion for reconsideration until August 25, 1989, the PCB considered the arguments raised therein without rejecting the motion as untimely. Thus, the record shows that the PCB itself perceived the August 10, 1989, opinion to be the final disposition of the application for site location approval and deemed the August 25, 1989, motion for reconsideration timely filed. The PCB also made no motion to dismiss the September 20, 1989, petition for review in this court as untimely.
Furthermore, the filing of a petition for review in this court functions as a notice of appeal (107 Ill. 2d R. 335) and causes the jurisdiction of the appellate court to attach instanter, depriving the administrative agency of jurisdiction to modify its judgment (see Bachewicz v. American National Bank & Trust Co. (1985), 135 Ill. App. 3d 294, 297-98, 482 N.E.2d 95, 98; Montgomery Ward & Co. v. Wetzel (1981), 98 Ill. App. 3d 243, 249, 423 N.E.2d 1170, 1176). Thus, once a petition for review has been duly filed, the administrative agency is restrained from taking any action which would change or modify the decision or its scope and from taking any action which would have the effect of interfering with the review of the decision. Bachewicz, 135 Ill. App. 3d at 297-98, 482 N.E.2d at 98; Dunn v. Dunn (1979), 71 Ill. App. 3d 649, 653, 390 N.E.2d 136, 139.
In the instant case, if Waste Management had treated the July 13, 1989, order as a final determination and filed a petition for review in this court, appellate jurisdiction would have attached instanter, precluding the PCB from modifying its order or issuing the August 10, 1989, opinion which recited the evidence and reasons leading to the earlier decision. Thus, when the July 13, 1989, order was issued, the process of administrative decision making had not yet reached a stage where judicial review would not disrupt the orderly process of adjudication. Port of Boston Marine Terminal Association, 400 U.S. at 71, 27 L. Ed. 2d at 210, 91 S. Ct. at 209; McHenry County Landfill, 154 Ill. App. 3d at 98, 506 N.E.2d at 378.
We believe the legislature intended that the final decision and supporting reasons be issued within 120 days and that this procedural requirement is mandatory and must be strictly applied. See Illinois Power Co. v. Pollution Control Board (1985), 137 Ill. App. 3d 449, 484 N.E.2d 898.
For all of the reasons set forth above, we hold that the August 10, 1989, opinion constituted the final determination by the PCB. Because the PCB failed to issue this opinion within the statutory time period, Waste Management’s application for site location of the waste transfer station must be deemed approved in accordance with the terms of section 40.1(a) of the Act. (Ill. Rev. Stat. 1987, ch. lll1^, par. 1040.1(a).) Having reached this conclusion, we need not consider the other issues raised by the parties.
For the foregoing reasons, the decision of the Illinois Pollution Control Board is reversed.
Reversed.