The issues raised by this cause are (1) whether, under R. C. Chapter 4906, the Power Siting Commission must normally defer to local judgment about power line tower designs, (2) whether the testimony of electrical engineers about the effect of electromagnetic fields on nearby animal and plant life constitutes competent expert witness testimony on which the commission may base its determination, and (3) what is the appropriate standard of review by this court of a Power Siting Commission determination.
Chester Township poses two basic arguments to this court. The first is that Ohio townships are “vested with the primary responsibility for regulating the size and design of new structures * * * within their jurisdictions” and, therefore, that the Power Siting Commission should defer to local judgment on tower designs unless the state can show that such deference “will conflict with an overriding state interest, place an unreasonable burden upon the applicant public utility or otherwise interfere with the ability of the public utility to carry out the project for which it seeks certification.” The second basic argument is that “[t]he testimony of expert witnesses” about the effect of electro-magnetic fields on plant and animal life “does not constitute substantial competent evidence upon which the commission may base its determination.”1
Appellant’s first argument is without merit. It is true *234that R. C. 519.02 grants township trustees the power to “regulate by resolution the location, height, bulk, number of stories, and size of buildings and other structures * * * in the unincorporated territory of such township * * *.” Appellant cannot, however, rely on R. C. Chapter 519 to argue that the Power Siting Commission must normally defer to local judgment, in view of the fact that R. C. 519.21 exempts from the local zoning control of R. C. 519.02 “any buildings or structures of any public utility * * * or the use of land by any public utility * * * for the operation of its business.”2
*235For similar reasons, the provisions of R. C. Chapter 4906 do not support the township’s contention that the commission must normally defer to local judgment oh tower designs. Although R. C. Chapter 4906 predicates the grant of an application to construct public utility facilities upon a commission finding that “the facility will serve the public interest, convenience and necessity,” and although it provides local governments with notice of the utility company’s application and makes them parties to the certification hearing, the Revised Code Chapter does not make local judgment control the commission’s choice of tower designs.3 On the contrary, R. C. 4906.10(A) requires that the commission base its decision to grant or deny an application on “the record.” Furthermore, R. C. 4906.13 and 4906.02(A) make it clear that approval of public utility construction plans, including the selection of tower designs, is a state matter. R. C. 4906.02(A) grants the commission *236statewide jurisdiction and requires that four of its five, members be drawn from existing state agencies. R. C. 4906.-13 provides, in pertinent part:
“No public agency or political subdivision of this state-may require any approval, consent, permit, certificate or other condition for the construction or initial operation of a major utility facility authorized by a certificate issued pursuant to Chapter 4906 of the Revised Code. * * *”
Given the fact that R. C. 4906.13 expressly prohibits, local governments from conditioning the construction or operation of R. C. Chapter 4906 public utility facilities on. local “approval” and given the fact that R. C. 4906.06(B) and 4906.08(A) (2) provide for investigating the claims and hearing the testimony of townships and applicants, we find appellant’s argument that township preferences as to tower designs should normally control to be without merit.4
Chester Township argues further that the commission erred in basing its determination that the electro-magneticfields surrounding power lines would not be detrimental to the public on the testimony of two electrical engineers; *237because such opinion testimony was “outside” the engineers’ “field, experience or discipline.” We do not find this argument convincing. The finder of fact has the power to make reasonable rulings as to the competency, admissibility and scope of expert testimony and to determine the weight to be accorded that testimony. Railroad Co. v. Defiance (1895), 52 Ohio St. 262, paragraph nine of the syllabus; McCormick On Evidence (2 Ed.) 29, Section 13; 21 Ohio Jurisprudence 2d 425, Evidence, Section-416. This rule is especially applicable to an R. C. Chapter 4906 proceeding because the General Assembly has granted the commission discretion, in its fact-finding role, to require such information, conduct such studies and adopt such rules of evidence as it deems necessary. R. C. 4906.10, 4906.03, and 4906.09.5 The engineers were called to testify in order to rebut the statements of another electrical engineer, and much of their testimony involved Comparing the electro-magnetic fields which would surround the proposed line with those which had surrounded the power lines studied in reports submitted as exhibits by appellant. Given the context in which the expert opinions concerning the danger of the electromagnetic fields were elicited, this court does not find that the commission abused its discretion in admitting and *238weighing their testimony. Appellant’s second argument is not well taken.
Implicit in appellant’s arguments concerning expert opinion testimony about electro-magnetic field effects and the deference to be given to local judgment about tower design, is a challenge to the commission’s determination on the grounds that it is against the weight of the evidence. Pursuant to R. C. 4906.12, this court must apply the same standard of review to Power Siting Commission determinations as we apply to orders by the Public Utilities Commission.
R. C. 4906.12 states:
“Sections 4903.02 to 4903.16 and Sections 4903.20 to 4903.23 of the Revised Code shall apply to any proceeding or order of the Power Siting Commission under Chapter 4906 of the Revised Code, in the same manner as if the commission were the Public Utilities Commission under such sections.”
R. C. 4903.13 provides:
“A final order made by the Public Utilities Commission shall be reversed, vacated, or modified by the Supreme Court on appeal, if, upon consideration of the record, such court is of the opinion that such order was unlawful or unreasonable.”
Under the “unlawful or unreasonable” standard of R. C. 4903.13, this court will not reverse or modify a determination unless it is manifestly against the weight of the evidence and so clearly unsupported by the record as to show misapprehension, mistake, or willful disregard of duty. Delphos v. Pub. Util. Comm. (1940), 137 Ohio St. 422, 424; Cleveland Electric Illuminating Co. v. Pub. Util. Comm. (1975), 42 Ohio St. 2d 403, paragraph eight of the syllabus; and General Motors Corp. v. Pub. Util. Comm. (1976), 47 Ohio St. 2d 58, paragraph two of the syllabus.
The commission’s findings that towers of lattice construction are preferable to those of pole construction chosen by the township trustees and that the electro-magnetic fields surrounding the towers will not be detrimental to nearby *239animal and plant life are not manifestly against the weight of the evidence. At the hearing, the commission was presented with substantial evidence that lattice towers are appropriate for the Chester Township area. Witnesses testified that the lattice design is well suited to the predominantly wooded landscape of Chester Township, that it is compatible with towers already built on the right of way which the proposed line will share, and that the lattice design costs 80 percent less than the tower design proposed by the trustees. The commission was also presented with sufficient information indicating that the electro-magnetic fields surrounding the proposed tower lines will not be detrimental. The secretary’s report came to that conclusion. Witnesses at the hearing concurred with the secretary’s report, and appellant’s evidence to the contrary was placed in doubt by the testimony of experts as to the voltage of the proposed power lines. In light of the considerable evidence in the record supporting the commission’s findings, we hold its determinations to be reasonable and lawful. The order of the Power Siting Commission is affirmed.
Order affirmed.
O’Neill, C. J., Herbert, Celebrezze, P. Brown and Sweeney, JJ., concur.In the reply brief which it submitted before this court, Chester Township raises, in addition to the two issues cited above, the question of whether the “record evidence” upon which the commission bases its decision, pursuant to R. C. Chapter 4906, is limited to evidence found only in the “transcript of the adjudicatory hearings conducted by the administrative law judge,” or whether it includes information from the application and the secretary’s staff report as well. Under R. C. 4906.12 most provisions of R. C. Chapter 4903 (including R. C. 4903.10) apply to proceedings conducted pursuant to R. C. Chapter 4906. R. C. 4903.10 provides in pertinent part:
*234“After any order has been made * * * any party who has entered an appearance in person or by counsel in the proceeding may apply for a rehearing in respect to any matters determined in said proceeding.
“Such application shall be in writing and shall set forth specifically the ground or grounds on which the applicant considers said order to be unreasonable or unlawful. No party shall in any court urge or rely on any ground for reversal, vacation, or modification not so set forth in such application.”
Appellant’s application for a rehearing was based on the argument that the expert witnesses relied on by the commission should not have been given credence because both were electrical engineers and, as such, they were “incompetent to render an opinion on the health hazards posed by high voltage transmission lines.” To support that contention appellant asserts:
“* * * And, the commission cannot remedy the deficiency by standing upon the tentative, incomplete and unsupported statements contained in the application * * * or upon the untested data submitted by the staff.”
Appellant’s passing reference to information in the application or secretary’s report, made in support of an evidentiary argument, is insufficient to constitute grounds for a last-minute statutory challenge to the inclusion of that information in the record. In Agin v. Pub. Util. Comm. (1967), 12 Ohio St. 2d 97, 98, this court stated:
“There is some similarity between parts of some of the grounds stated in appellants’ application for rehearing before the commission and parts of some of the statements of law in appellants’ brief on appeal in this court. Such a casual similarity does not, however, meet the requirements of Section 4903.10, Revised Code * *
The same principle applies to the instant cause.
R. C. 519.21 provides that Sections 519.02 to 519.25, inclusive, of the Revised Code, “confer no power on any board of township trustees *235or board oí zoning appeals in respect to the location, erection, construction, reconstruction, change, alteration, maintenance, removal, use, or enlargement of any buildings or structures of any public utility or railroad, whether publicly or privately owned, or the use of land by any public utility or railroad, for the operation of its business.”
R. C. 4906.10(A) requires the commission to “render a decision upon the record” granting or denying an application, only after it finds and determines:
“ (1) The basis of the need for the facility;
“ (2) The nature of the probable environmental impact;
“(3) That the facility represents the minimum adverse environmental impact, considering the state of available technology and the nature and economics of the various alternatives, and other pertinent ■considerations;
“(4) In case of an electric transmission line, that such facility is ■consistent with regional plans for expansion of the electric power grid •of the electric systems serving this state and interconnected utility systems; and that such facilities will serve the interests of electric system economy and reliability;
“(5) That the facility will comply with Chapters 3704, 3734, and 6111 of the Revised Code and all regulations and standards adopted thereunder;
“(6) That the facility will serve the public interest, convenience, and necessity.”
R. C. 4906.06(A) requires that “[a]n applicant for a certificate *236shall file with the Power Siting Commission an application * *
R. C. 4906.06(B) provides:
“Each application shall be accompanied by proof of service of a. copy of such application on the chief executive officer of each municipal corporation and county and the head of each public agency, charged with the duty of protecting the environment or of planning land use, in, the area in which any portion of such facility is to be located.”
The dissent argues in effect: (1) that tower designs are a question of aesthetics, (2) that aesthetic questions are capable only of subjective responses, and (3) that local governing boards should decide which tower designs are aesthetically pleasing since they have to live with them. The fact is, however, that R. C. Chapter 4906 requires the commission to rule on the “environmental impact” of such proposed public utility constructions as power line towers. That the analysis, of the “environmental impact” of a tower necessarily involves a judgment as to its aesthetic appeal does not change the thrust of the statute. The question of aesthetics, like those of “need,” consistency* with regional expansion plans and “public interest, convenience and necessity” must be resolved by the commission (R. C. 4906.10) and not. by one of the parties.
Under R. C. 4906.03, the commission shall:
“(C) Require such information from persons subject to its jurisdiction as it considers necessary to assist in the conduct of hearings and any investigations or studies it may undertake;
“(D) Conduct any studies or investigations which it considers necessary or appropriate to carry out its responsibilities under this chapter;
“(E) Adopt rules establishing criteria for evaluating the effects on environmental values of proposed and alternative sites, and projected needs for electric power, and such other rules as are necessary and convenient to implement Chapter 4906 of the Revised Code, including reasonable application fees.”
R. C. 4906.09 provides:
“A record shall be made of the hearing and of all testimony taken. Rules of evidence, as specified by the Power Siting Commission, shall apply to the proceeding. The commission may provide for the consolidation of the representation of parties having similar interests.”