OPINION OF THE COURT
Pigott, J.Respondent Kevin Nowack, a firefighter employed by petitioner Ridge Road Fire District, claimed to have sustained a back injury while on duty on November 7, 2002. Specifically, Nowack claimed that the fire truck he was driving hit a “low spot,” manhole cover or pothole in the road, causing the truck’s air suspension seat to elevate and “shoot” downward, causing a “twinge” or “tightness” in his low back.
Nowack sought General Municipal Law § 207-a benefits, to which certain firefighters are entitled if they are “injured in the performance of [their] duties” (General Municipal Law § 207-a [1]). He completed an “accident-sickness packet” containing, among other things, an employee injury report, physician report and authorization for medical records. The District denied Nowack’s application finding that his complained-of injury was a preexisting one that he sustained while off duty.
Nowack requested a hearing with respect to the District’s denial of benefits in accordance with the Collective Bargaining Agreement (CBA) between the District and respondent Ridge Road Professional Firefighters Association IAFF, Local 3794. The CBA provides that a hearing officer “shall conduct the hearing in accordance with the established rules of evidence, consistent with the NYS Administrative Procedure Act,” and that “[i]t is the employee[’s] burden to prove [that he] is entitled to GML 207-a benefits.” The hearing was held before respondent hearing officer Michael Schiano. Nowack and the District *498each called witnesses and presented evidence relative to their respective theories of causation.
In his written decision, the hearing officer stated, incorrectly, that the standard of review was “whether or not substantial evidence was presented to override the Fire District’s Determination” (emphasis supplied), and concluded that there was and that Nowack was therefore entitled to section 207-a benefits. The District challenged this determination in a CPLR article 78 proceeding. Supreme Court granted the petition, annulled the decision, and remanded the proceeding, directing the hearing officer to apply the proper standard of review, namely, whether the District’s determination denying Nowack benefits was supported by substantial evidence.
On remand, the hearing officer’s second decision proffered the same analysis word-for-word as his first and stated the proper standard of review, but nonetheless concluded that the District’s denial of Nowack’s section 207-a benefits was not supported by substantial evidence. The District again challenged that determination and Supreme Court granted the District’s petition, vacated the decision and reinstated the District’s original denial of section 207-a benefits. Supreme Court held that the hearing officer’s decision was arbitrary and capricious, and noted that the District’s determination denying benefits “was supported by substantial evidence in the record as a whole despite the fact that there was conflicting medical evidence to support a contrary result.”
The Appellate Division reversed and dismissed the petition, holding that the District’s “denial of benefits, which was based on the determination that the disability was solely related to a prior non-work-related injury, [was] not supported by substantial evidence” (67 AD3d 1342, 1345 [4th Dept 2009]). This Court granted leave, and we reverse.
Under the CBA, the hearing officer was required to “conduct the hearing in accordance with the established rules of evidence, consistent with the [New York State] Administrative Procedure Act.” That Act provides, in relevant part, that “[n]o decision, determination or order shall be made except upon consideration of the record as a whole or such portion thereof as may be cited by any party to the proceeding and as supported by and in accordance with substantial evidence” (State Administrative Procedure Act § 306 [1] [emphasis supplied]). The parties here agree, and we therefore assume, that, *499as applied to this case, the statute requires the District’s denial of benefits to be upheld if substantial evidence supports it. Therefore, in accordance with this standard and in light of the CBA’s terms, the independent hearing officer was required to give deference to the District’s decision and Nowack bore the burden of establishing that the District’s denial determination had not been supported by substantial evidence.
This Court has defined “substantial evidence” as such relevant proof as a reasonable mind may accept as adequate to support a conclusion or ultimate fact, and “is less than a preponderance of the evidence, overwhelming evidence or evidence beyond a reasonable doubt” (300 Gramatan Ave. Assoc. v State Div. of Human Rights, 45 NY2d 176, 180-181 [1978]). The standard “demands only that ‘a given inference is reasonable and plausible, not necessarily the most probable’ ” (Matter of Miller v DeBuono, 90 NY2d 783, 793 [1997], quoting Borchers and Markell, New York State Administrative Procedure and Practice § 3.12, at 51 [1995]).
Viewing this record as a whole, Supreme Court correctly held that the hearing officer’s decision, i.e. that the District’s denial of section 207-a benefits was not based on substantial evidence, was arbitrary and capricious. The District’s evidence consisted of testimony from its medical expert that Nowack’s back injury was not causally related to the November 2002 incident, but was instead attributed to a fractured lumbar vertebra he had sustained in an accident in 1993 and an August 4, 2002 injury. The battalion chief testified that, after Nowack told him that he was experiencing back pain, he prepared an initial report. During his investigation, Nowack did not relate the version of events he now claims is the cause of his injury— that the air suspension seat on a fire truck had malfunctioned— nor did he tell him that he hit a “low spot” or “pothole” in the road. The District offered the further testimony of its group battalion chief, who stated that he had contacted the District mechanic and a representative of the manufacturer, who each examined the seat and found nothing wrong with its operation or adjustment mechanisms. This evidence was significant in light of the testimony by Nowack’s neurosurgeon that if the accident did not occur in the manner that Nowack claimed, then he would not causally relate Nowack’s injury to a work-related incident. Based on the foregoing, it is clear that there was substantial evidence supporting the District’s denial of benefits, and the hearing officer’s conclusion to the contrary was irrational as a matter of law.
*500It is of no consequence that the record also indicates that there was evidence supporting Nowack’s contention. Quite often there is substantial evidence on both sides. The applicable standard here was whether the District’s denial of benefits was supported by substantial evidence. Thus, the dissent errs in suggesting that, because either side might reasonably have prevailed, we are required to uphold the hearing officer’s ruling. To the contrary, since, as all Judges of this Court agree, there is unquestionably substantial evidence supporting both sides’ positions, the hearing officer acted arbitrarily in deciding that none supported the District’s. The order of the Appellate Division should be reversed, with costs, and the judgment of Supreme Court reinstated.