Everette J. Brown, an electrician for Alabama Electric Company, arrived at the Potlatch job site in Cypress Bend the morning of July 12, 1994. His foreman asked him to drive to McGehee to get cutting oil. On the way to McGehee at about 8:35 a.m., his company truck left the highway and hit a tree. Mr. Brown was taken to the emergency room of Desha County Hospital and then transferred to Jefferson Regional Medical Center for treatment of a fractured right femur. A urine specimen collected shortly after he arrived at Jefferson Regional was sent to a laboratory for testing. The laboratory analysis, performed by gas chromatography mass spectrometry testing, revealed the presence of marijuana metabolites in the urine.
Alabama Electric and its carrier controverted the claim for workers’ compensation benefits, contending that Mr. Brown’s injuries were not compensable under the law. Appellees argue that the presence of marijuana in his body at the time of or immediately after the accident raised the statutory presumption that the injury was substantially occasioned by the illegal substance. The administrative law judge awarded benefits after finding that Mr. Brown sustained his burden of proof by a preponderance of the credible evidence that he had sustained the injury arising out of and in the course of his employment. The Workers’ Compensation Commission reversed in a two to one decision, finding that Mr. Brown had not rebutted the statutory presumption that the accident was substantially occasioned by the use of marijuana. Mr. Brown now appeals, contending that 1) there was no substantial evidence to invoke the presumption, and the Commission abused its discretion by invoking the presumption; and 2) the Commission had no substantial basis to deny relief to appellant, and it abused its discretion by disbelieving his testimony and ignoring other evidence of record. We address the issues as appellant presents them.
I. There was an absence of substantial evidence to invoke the presumption of Ark. Code Ann. § li-9-103(b)(iv), and the Commission abused its discretion by invoking the presumption.
A prima facie presumption existed under our prior workers’ compensation law that an injury did not result from intoxication of the injured employee while on duty. Ark. Code Ann. § 11 — 9— 707(4) (1987). Act 796 of 1993 changed that presumption: Arkansas Code Annotated § ll-9-102(5)(B)(iv) (Repl. 1996) now reads in pertinent part:
(B) “Compensable injury” does not include:
(iv)(a) Injury where the accident was substantially occasioned by the use of alcohol, illegal drugs, or prescription drugs used in contravention of physician’s orders.
(b) The presence of alcohol, illegal drugs, or prescription drugs used in contravention of a physician’s orders shall create a rebuttable presumption that the injury or accident was substantially occasioned by the use of alcohol, illegal drugs, or prescription drugs used in contravention of physician’s orders.
(c) Every employee is deemed by his performance of services to have impliedly consented to reasonable and responsible testing by properly trained medical or law enforcement personnel for the presence of any of the aforementioned substances in the employee’s body.
(d) An employee shall not be entided to compensation unless it is proved by a preponderance of the evidence that the alcohol, illegal drugs, or prescription drugs utilized in contravention of the physician’s orders did not substantially occasion the injury or accident.
Ark. Code Ann. § 11-9-102(5)(B)(iv) (Repl. 1996).
In its decision, the Commission referred to the statute above and wrote, “In the present claim, the evidence shows that marijuana was present in the Claimant at the time of the injury. Therefore, we begin with the assumption that the Claimant’s injury was substantially occasion [sic] by the drug.” Appellant presents the threshold issue of whether there was substantial evidence upon which the Commission could base the presumption that the injury was substantially occasioned by marijuana.
Evidence presented at the hearing included a drug-testing report by Dr. H. H. Miller, Ph.D., a pharmacologist and director of toxicology at Corning Clinical Laboratories; deposition testimony of Dr. Henry F. Simmons, Jr., a toxicologist and medical doctor who reviewed Dr. Miller’s report; and testimony of appellant.
Appellant testified that he had smoked marijuana about three weeks before the accident but had not done so since, keeping a vow made to his wife on their wedding day, July 1. He denied smoking marijuana the morning of the accident. He stated that he had lost control of the truck when it hydroplaned in a rainstorm.
Dr. Miller’s report stated that the level of marijuana metabolites detected in the laboratory analysis was consistent with drug ingestion. His report went on to say, however:
I cannot determine when, in what manner, in what quantity, or whether legal or illegal drug use occurred. Neither can I draw any conclusions about whether the individual was impaired or intoxicated at the time the specimen was collected. Impairment is a function of the level of the active parent drug which is presented to the central nervous system via the arterial blood supply and bears no relationship to the metabolic level found in the urine.
Dr. Henry Simmons, who reviewed Dr. Miller’s report for appellant, testified by deposition as follows:
The urine tests in and of themselves, at least through the [Department of Transportation] programs, are not used to determine the dose, to determine the dosing time, or determine the point of impairment.
There are tests that can be conducted on blood, the results of which would more likely be connected to acute use and impairment than the tests that are conducted on urine.
[A blood test] would dramatically narrow the framework. For example, an individual who had a significant quantity of the primary psychoactive ingredient of marijuana that was actually measurable in his blood, namely THC, is an individual who has used the drug within a very short time frame, say minutes to a few hours; as opposed to the presence of metabolites or breakdown products of THC in the urine which could be present under some circumstances for literally weeks after last use.
Under cross-examination, this exchange took place:
Q. And the level as shown on the July 12, 1994, report is consistent with Mr. Brown having been impaired on that date; is that right, sir?
A. A better way to state it would be that the presence of the metabolites— in his urine given on July the 12th of ’94 [is] consistent with impairment on that day. But by no means specific for impairment.
When questioned about his familiarity with effects of marijuana metabolites on the central nervous system, Dr. Simmons answered, “[M]ore appropriately, not metabolites in general, but the THC itself. Certainly, not all of the metabolites are psychoactive.” He stated that THC is the primary component affecting the central nervous system and can, in sufficient dosage, cause problems with perception, balance or coordination, reaction and response time, dizziness and light-headedness, loss of judgment, and possibly involvement in a motor-vehicle accident. He stated that his opinions in this case were based upon his believing appellant’s testimony.
On redirect examination, Dr. Simmons said:
There is nothing about the test that can be conclusively linked by itself to impairment at any particular time. The test alone could just as easily be consistent with not being impaired at all. [One can] not tell from this test whether or not the person was impaired. Absolutely not. You cannot tell from this test whether he was impaired. It would be fair to state that this test is inconclusive as far as whether or not a person was impaired on the date of the accident.
Appellant notes statements by Dr. Miller and Dr. Simmons that urine tests cannot show intoxication or impairment at the time the specimen was taken, and that the tests cannot determine the time or manner of use, the quantity used, or whether usage was legal or illegal. Appellant contends that the report thus did not meet the statutory requirements for “reasonable and responsible testing” by “properly trained medical or law enforcement personnel” of Arkansas Code Annotated § ll-9-102(5)(B)(iv)(c); and that it was not properly certified. Appellant contends that the presence of marijuana metabolites in his urine was not evidence of the presence of marijuana and that, therefore, the presumption that the injury or accident was substantially occasioned by the use of illegal drugs did not arise. See Ark. Code Ann. § 11-9-102(5)(B)(iv)(b).
Arkansas Code Annotated section 11-9-102 does not require that the Commission promulgate drug-testing procedures or specify particular types of tests to be used as a precondition to the intoxication presumption. The Arkansas General Assembly could have required testing that would show a certain level of illegal drugs, as it has required to invoke the presumption in D.W.I. cases, but it has not made such a requirement. The Commission has broad discretion with reference to admission of evidence, and its decision will not be reversed absent a showing of abuse of its discretion. We find no abuse of discretion in the Commission’s considering the report on urine testing as evidence of the presence of drugs under Arkansas Code Annotated section 11-9-102(5)(B)(iv) (Repl. 1996). Neither do we find that there was an absence of substantial evidence for the Commission to invoke the presumption that appellant’s accident was substantially occasioned by the use of marijuana.
II. The Commission had no substantial basis to deny relief to appellant, and the Commission abused its discretion when it disbelieved his testimony and ignored other evidence of record.
When a claim is denied because a claimant fails to show entitlement to compensation by a preponderance of the evidence, the substantial-evidence standard of review requires that we affirm if a substantial basis for the denial of relief is displayed by the Commission’s opinion. Linthicum v. Mar-Bax Shirt Co., 23 Ark. App. 26, 741 S.W.2d 275 (1987). It is well established that the credibility of witnesses and the weight to be given their testimony are matters exclusively within the province of the Commission. Wade v. Mr. C. Cavenaugh’s, 298 Ark. 363, 768 S.W.2d'521 (1989).
Appellant points to statements in the Commission’s opinion that the only evidence pertaining to the cause of the accident was appellant’s own testimony and that there is no corroborative testimony of how the accident occurred. He contends that the Commission ignored the investigating officer’s decision not to mark alcohol and drugs as contributing factors, medical records reporting that he was awake and alert after the accident, and the absence of any notations by medical personnel that would indicate impairment or intoxication.
The Commission addressed in its opinion the question of whether appellant’s denial of having used marijuana on the date of the accident was sufficient to constitute a preponderance of the credible evidence and rebut the presumption that the accident was substantially occasioned by the use of marijuana. It is clear that the Commission did not believe appellant’s testimony that he had not smoked marijuana in three weeks. Furthermore, the Commission stated, “An admission of prior drug use, a positive drug test on the day of the accident, and two expert toxicologist’s testimony that the test results could not pinpoint the time of use does not add up to a preponderance of the evidence that the accident was not substantially [occasioned] by drug use.”
We cannot conclude that the Commission’s decision failed to display a substantial basis for the denial of the claim. Furthermore, the Commission based its decision on the evidence to which it assigned the greater weight.
Affirmed.
Bird, J, agrees. Arey, Crabtree, and Roaf, JJ., concur. Griffen, J., dissents.