dissenting.
As I believe the majority has not properly applied the competent evidence standard required by this Court in its review of decisions by the North Carolina Industrial Commission and has ignored the burden imposed on defendants by N.C. Gen. Stat. § 97-12, I respectfully dissent. I restate the facts in order to aid the analysis below.
On 17 November 1997, William Henry Mullins (Mullins) died when his truck ran off the road and overturned during the course and in the scope of his employment with Williamson Produce.1 A post mortem urinary drug screen indicated the presence cocaine and marijuana metabolites, the waste products of cocaine and marijuana, in Mullins’ system. Deposition testimony of Dr. Arthur John McBay (McBay), an expert in forensic toxicology, revealed that based on the reports available, it was impossible to determine the actual amount of cocaine and marijuana in Mullins’ system at the time of the accident. The available reports included a toxicology report of a drug screen performed on Mullins using a minimum threshold of 300 nanograms of cocaine metabolites present in a person’s urine as the cut-off rate for a positive test for cocaine.2 McBay stated that it was impossible to establish from Mullins’ urinary drug screen whether either drug was introduced into Mullins’ system within twelve hours of the accident or how they were administered into his system. McBay explained that cocaine, depending on the quantity, can stay in a person’s system for three to four days, whereas a test for marijuana can show positive for over twenty days. The pharmacological effect of the drugs, which measures the level of impairment experienced by a person, however, cannot be determined by a mere urine drug screen.
Dr. Arthur E. Davis, Jr. (Davis) testified at his deposition as an expert in pathology and toxicology. Davis had performed a documentary autopsy on Mullins by reviewing the crash report, offense/case report, coroner’s verdict, death certificate, and toxicology reports. He testified that the threshold established by the federal government of 300 nanograms per millimeter is a sufficient level to have a pharmacological effect on a person. The height and weight of an individual are irrelevant when determining the absorption of cocaine into an individual’s system. Moreover, a urine test is the only test to use in *85order to determine whether cocaine is still having an effect on an individual which would impair his ability to drive. Because of the amount of cocaine metabolites found in Mullins’ system, Davis found by “a reasonable [degree of] medical certainty as a physician, that [Mullins] used cocaine almost assuredly within the last six to twelve hours [prior to the accident] and that he was [at that time] still under the influence of cocaine and it was having a profound, adverse effect on his driving ability.”3
On appeal from the deputy commissioner, the Full Commission (the Commission) found in pertinent part that:
5. A urinary drug screen was performed post mortem [on Mullins] which showed a positive screen for the metabolites for cocaine and marijuana .... The cut[-]off for the drug screen for the cocaine metabolite is 300 nanograms. A nanogram is a billionth of a gram. There was no evidence of the quantitative amount of the cocaine or marijuana metabolites in [Mullins’] system at the time of the accident which resulted in his death.
6. There is no evidence of when either cocaine or marijuana entered [Mullins’] system, how much was introduced or the mode of administration. It is possible for an individual to test positive for the cocaine metabolite for 3 or 4 days after it is introduced [in]to their system. It is possible to test positive for the marijuana metabolite for as long as 20 days after it is introduced [in]to an individual’s system.
7. Based on the post mortem urine drug screen performed on [Mullins’] body, there is no scientific basis for determining what impact, if any, the drug metabolites had on [Mullins] at the time of the accident. Drug screens are only meant to demonstrate an analytically significant amount of a metabolite, not a pharmaco-logically significant amount. An analytically significant amount simply means an amount that can be determined with certainty. A pharmacologically significant amount is an amount that has a measurable effect on an individual. Therefore, it cannot be shown that 300 nanograms of the metabolite of cocaine in [Mullins’] urine had a measurable pharmacological effect on him at the time of the accident.
*868. The opinion of [Davis] that [Mullins] was impaired at the time of the accident is not given any weight. [Davis] based his opinion on a review of only four documents. He did not know [Mullins’] height, weight, medical history, when cocaine was introduced [in]to [Mullins’] system or how much was introduced. As such, [Davis’] opinions regarding [Mullins’] potential impairment or intoxication at the time of the accident were given on an inadequate factual basis to be accepted. [Davis] provided no opinion on the effect of the marijuana metabolites on [Mullins] at the time of the accident.
10. [McBay] has extensive experience in the area of forensic toxicology and has served as the Chief Toxicologist at the Office of Chief Medical Examiner in North Carolina. [McBay] testified that based on the data obtained subsequent to [Mullins’] death that it is impossible to determine the time and means of administration of marijuana or cocaine into [Mullins’] system. . . . [The Commission] gives great weight to the opinions of [McBay].
11. Defendants have failed to produce sufficient evidence to prove that the accident which resulted in [Mullins’] death was proximately caused by [Mullins] being under the influence of cocaine or marijuana or that he was intoxicated at the time it occurred.
The Commission subsequently concluded that Plaintiff was not barred from recovering compensation because defendants had not met their burden under N.C. Gen. Stat. § 97-12 to show the accident was proximately caused by a drug impairment.
The dispositive issue is whether there was competent evidence to support the Commission’s findings that “it cannot be shown that 300 nanograms of the metabolite of cocaine in [Mullins’] urine had a measurable pharmacological effect on him at the time of the accident,” and defendants therefore did not “produce sufficient evidence to prove that the accident... was proximately caused by [Mullins] being under the influence of cocaine.”
Appellate review of an opinion and award by the Commission “is limited to a determination of (1) whether the findings of fact are supported by competent evidence, and (2) whether the conclusions of law are supported by the findings.” Barham v. Food World, 300 N.C. *87329, 331, 266 S.E.2d 676, 678, (1980). This Court “ ‘does not have the right to weigh the evidence and decide the issue on the basis of its weight. The [C]ourt’s duty goes no further than to determine whether the record contains any evidence tending to support the finding.’ ” Deese v. Champion Int’l Corp., 352 N.C. 109, 115, 530 S.E.2d 549, 552 (2000) (quoting Anderson v. Lincoln Constr. Co., 265 N.C. 431, 434, 144 S.E.2d 272, 274 (1965)). “[T]his Court is bound by such evidence, even though there is [other] evidence that would have supported a finding to the contrary.” Porterfield v. RPC Corp., 47 N.C. App. 140, 144, 266 S.E.2d 760, 762 (1980). Moreover, the Commission is “the sole judge of the credibility of the witnesses and the weight to be given their testimony.” Melton v. City of Rocky Mount, 118 N.C. App. 249, 255, 454 S.E.2d 704, 708 (citation omitted), disc. review denied, 340 N.C. 568, 460 S.E.2d 319 (1995).
Under the Workers’ Compensation Act, “[n]o compensation shall be payable if the injury or death to the employee was proximately caused by . . . [h]is being under the influence of any controlled substance.” N.C.G.S. § 97-12 (1999). The burden rests on the employer to prove that an employee’s intoxication or impairment was “more probably than not a cause in fact of the accident resulting in injury to the employee.” Anderson v. Century Data Systems, 71 N.C. App. 540, 545, 322 S.E.2d 638, 641 (1984), cert. denied, 313 N.C. 327, 327 S.E.2d 887 (1985).
In this case, the Commission was presented with conflicting expert testimony regarding the question of whether Mullins’ driving ability was impaired by drugs at the time of his accident. Davis testified 300 nanograms of cocaine metabolites found in a person’s urine indicates impairment. McBay, on the other hand, stated it was impossible to determine a person’s impairment from a urinary drug screen. Thus, in accepting one expert’s opinion, the Commission necessarily had to reject the testimony of the other expert. Accordingly, if the Commission' believed McBay’s testimony that it was impossible to establish from the urinary drug screen whether cocaine was introduced into Mullins’ system within twelve hours of the accident, the Commission had to find that Davis could not have known “when cocaine was introduced [in]to [Mullins’] system,” thus rejecting Davis’ testimony “that [Mullins] used cocaine almost assuredly within the last six to twelve hours” prior to the accident. The Commission also accepted McBay’s testimony that it was impossible to determine the actual amount of cocaine in Mullins’ system at the time of the *88accident. Consequently, the Commission was justified in rejecting Davis’ opinion on the basis that “ [h]e did not know . . . when cocaine was introduced [in]to [Mullins’] system or how much was introduced.”
The majority holds that Davis’ testimony presented competent evidence. Even if this were so, it would not warrant a reversal of the Commission’s opinion and award. See Porterfield, 47 N.C. App. at 144, 266 S.E.2d at 762 (“[i]f there is any evidence of substance which directly or by reasonable inference tends to support the findings, this Court is bound by such evidence, even though there is evidence that would have supported a finding to the contrary”). McBay’s experience with the threshold for the cocaine metabolites and his testimony that impairment could not be established by a urinary drug screen using this threshold was sufficient to support the Commission’s finding that “it cannot be shown that 300 nanograms of the metabolite of cocaine in [Mullins’] urine had a measurable pharmacological effect on him at the time of the accident,” and in turn supported the finding that defendants failed to meet their burden under section 97-12 to show Mullins’ death “was proximately caused by [his] being under the influence of cocaine.”
The majority finds significance in the fact that the Commission noted in its findings of fact that the accident occurred at 11:20 p.m. and that McBay testified to fatigue as the leading cause of single tractor-trailer accidents. The majority reads these findings as an implicit finding of causation. Nowhere in its opinion and award, however, does the Commission make a finding as to what caused the accident. The only finding on the issue of causation relates to defendants’ failure to show that impairment was more probable than not a cause in fact of the accident. The majority’s reliance on the above findings in reversing the Commission’s opinion and award is thus misplaced because it ignores the burden on the party asserting the defense of impairment under section 97-12.4 See Anderson, 71 N.C. App. at 545, *89322 S.E.2d at 641. The Commission’s only obligation was to find whether defendants had met their burden, and the Commission did so based on competent evidence. The issue of fatigue played no role in this analysis.
Finally, in holding there is a lack of sufficient competent evidence to support the Commission’s finding as to defendants’ failure to meet their burden of proof, the majority focuses on the competence of Davis’ testimony and the accounts of the eyewitnesses. As noted above, this analysis does not comply with our standard of review on appeal, which is to decide whether there is any competent evidence to support the Commission’s findings, not whether there was any competent evidence to support a different finding. See Porterfield, 47 N.C. App. at 144, 266 S.E.2d at 762. In weighing expert testimony, issues of credibility remain within the sole discretion of the Commission and cannot be second-guessed on appeal. Melton, 118 N.C. App. at 255, 454 S.E.2d at 708.
Because McBay’s testimony supports the Commission’s finding that impairment could not be established and therefore defendants failed to meet their burden under section 97-12, I would uphold the Commission’s opinion and award.
. The parties do not dispute this fact.
. McBay testified he established this threshold amount for the detection of cocaine metabolites for the Department of Defense when it wanted to detect the activity of drug use, not the impairment caused by drugs.
. Davis also expressed an opinion that Mullins was under the toxic effect of marijuana at the time of the accident. Because Davis gave no factual basis for this conclusion, this analysis focuses solely on the possible impairment a person might suffer with 300 nanograms of cocaine metabolites in his system.
. The majority reads section 97-12 as merely imposing on the employer the burden of proving the use of a non-prescribed controlled substance by the employee. Once the employer has met this requirement, the majority holds, the burden shifts to the employee to prove that the use of the controlled substance was not a contributing proximate cause of the accident. In support of its position, the majority cites several statutes enacted by other states that provide for a rebuttable presumption of impairment sufficient to satisfy the causation requirement once intoxication or the presence of a controlled substance has been shown. While the trend reflected in these statutes may support a legislative change in our laws, section 97-12, the statute in effect in North Carolina at this time, does not include such language. The plain language of our statute dictates that for “an injury or death” to be “proximately caused by” an employee *89“being under the influence of any controlled substance,” the controlled substance must have an impairing effect on the employee. N.C.G.S. § 97-12. Without a showing of impairment, there cannot be causation, and without a showing of causation, the employer has not sustained its burden under the statute. See Anderson, 71 N.C. App. at 545, 322 S.E.2d at 641.