[1J Plaintiffs first claim for relief is based on G.S. 97-6.1, which reads, in relevant part, as follows:
(a) No employer may discharge or demote any employee because the employee has instituted or caused to be instituted, in good faith, any proceeding under the North Carolina Workers’ Compensation Act, or has testified or is about to testify in any such proceeding.
(b) Any employer who violates any provision of this section shall be liable in a civil action for reasonable damages suffered by an employee as a result of the violation, and an employee discharged or demoted in violation of this section shall be entitled to be reinstated to his former position. The burden of proof shall be upon the employee.
To recover under the statute, the plaintiff must show: (1) discharge or demotion, (2) caused by good faith institution of workers’ compensation proceedings, or testimony or anticipated testimony, in those proceedings. Hull v. Floyd S. Pike Electrical Contractor, 64 N.C. App. 379, 307 S.E. 2d 404 (1983). Plaintiff argues the trial court erred in granting summary judgment for defendant on his claim of retaliatory discharge. We agree.
Summary judgment should only be granted where the evidence presented to the trial court shows that there is no genuine issue of material fact and that the movant is entitled to judgment as a matter of law. Bank v. Gillespie, 291 N.C. 303, 230 S.E. 2d *350375 (1976); G.S. 1A-1, Rule 56(c). The movant’s materials must be closely scrutinized while the non-movants must be indulgently regarded. Hillman v. United States Liability Ins. Co., 59 N.C. App. 145, 296 S.E. 2d 302 (1982), disc. rev. denied, 307 N.C. 468 (1983). Defendants contend they are entitled to summary judgment because there is no genuine issue of material fact as to (1) plaintiff s discharge, (2) its motive in discharging plaintiff, assuming he was discharged, and (3) the existence of certain affirmative defenses found in subsections (c) and (e) of the statute. The evidence presented to the trial court, however, precludes summary judgment on any of those grounds.
The evidence undoubtedly reveals a factual dispute on whether plaintiff was discharged. Defendants showed that it was company and industry practice to consider that drivers who left their trucks on the route had quit their job. Moreover, plaintiff was told that in his conversation with the dispatcher on 14 August 1985. Merely because an employer considers an employee as having quit his job, however, does not necessarily make it so, even if the employer had such a policy or practice and the employee knew about it. The proper inquiry in determining whether he was discharged is whether the employee voluntarily left his position, not whether he chose to do an act for which he knew his employer would fire him. Plaintiffs materials showed that he did not want to lose his job; that he told the dispatcher he was not quitting but merely returning to North Carolina to see his doctor about his recurring pain; and that, when he returned to the terminal, Mr. Doyle Vaughn, defendants’ terminal manager, asked plaintiff to turn in his keys and credit cards. This is sufficient to establish a genuine issue of material fact regarding whether defendant was discharged.
Assuming arguendo that plaintiff was discharged, there is also a genuine issue of material fact as to defendants’ motive in discharging plaintiff. Mr. McNabb’s and Mr. Vaughn’s depositions indicate that the only reason plaintiff was fired, again assuming he was fired, was that he violated company work rules by leaving his truck in Pennsylvania and returning home without it. In plaintiffs deposition testimony, however, there is enough evidence of a retaliatory motive to make summary judgment on that basis inappropriate.
*351Plaintiff testified that both Mr. McNabb and Mr. Vaughn told him several times after he returned from the California trip and when he complained about his leg, that he should get another job if his injury prevented him from driving. Plaintiff also testified that he felt like he was assigned the California trip to “get rid of” him and that he was sent on the trips to the northeastern United States to “test [him] out.” Plaintiff also testified that, during his medical treatment, he missed several doctor’s appointments because “they kept me out — when they knew that I had an appointment.” In addition, plaintiffs evidence that the dispatcher refused to assign him the easier routes, that easier routes may have been available for assignment to him, and that his fellow drivers did not see why plaintiff could not have those easier routes, is further evidence that defendants’ motive was retaliatory.
Plaintiff’s evidence showing defendants had a retaliatory motive is all circumstantial. Moreover, defendants’ materials attempt to refute much of it. However, motive, like intent or other states of mind, is rarely susceptible to direct proof and almost always depends on inferences drawn from circumstantial evidence. See Brandis, North Carolina Evidence, section 83 (1982). Consequently, summary judgment should rarely be granted in those cases. See Bank v. Belk, 41 N.C. App. 328, 255 S.E. 2d 430, disc. rev. denied, 298 N.C. 293, 259 S.E. 2d 299 (1979). Furthermore, where matters of the credibility and weight of the evidence exist, summary judgment ordinarily should be denied. Moore v. Field-crest Mills, Inc., 296 N.C. 467, 251 S.E. 2d 419 (1979). The weight and credibility of both defendants’ and plaintiff’s evidence, must be determined by the finder of fact.
 Finally, defendants contend the summary judgment may be sustained due to the existence of certain statutory defenses set out in G.S. 97-6.1(c) and (e). We disagree.
Defendants rely on G.S. 97-6.1(c) and (e):
(c) Any employer shall have as an affirmative defense to this section the following: . . . failure to meet employer work standards not related to the Workers’ Compensation Claim.
(e) The failure of an employer to continue to employ, either in employment or at the employee’s previous level of *352employment, an employee who receives compensation for permanent total disability, or a permanent partial disability interfering with his ability to adequately perform work available, shall in no manner be deemed a violation of this section. [Emphasis added.]
Initially the parties dispute the effect of subsections (c) and (e) on proof of the employer’s motive under subsection (a). Plaintiff argues that the employer’s motive in discharging or demoting the employee is relevant even if the employer can show it has a defense under subsection (c) or (e). Defendants argue that once the employer shows it has a subsection (c) or (e) defense, inquiry into the employer’s motive becomes irrelevant. Under defendants’ analysis, once a defense is established, even if a plaintiff could prove that his employer fired him for pursuing his remedies under the Workers’ Compensation Act, the employer would nevertheless receive judgment. Both parties cite language from Johnson v. Builder’s Transport, Inc., 79 N.C. App. 721, 340 S.E. 2d 515 (1986), in support of their position. We need not, however, address that question since, even assuming that defendants’ analysis is correct, summary judgment was improperly granted.
All of the evidence shows that any failure to meet defendants’ work standards was due to the injury which was the subject of plaintiff’s workers’ compensation claim and his desire to seek medical attention for it. Therefore, the failure to meet work standards is related to his workers’ compensation claim and not within the purview of subsection (c).
Similarly, under subsection (e), defendants have failed to establish that plaintiffs permanent partial disability interfered with his ability to perform work available. It is undisputed that plaintiff sustained a permanent partial disability in his left leg. Prior to the statute’s amendment in 1985, proof of this fact alone would have established a defense. See Bridgers v. Whiteville Apparel Corp., 71 N.C. App. 800, 323 S.E. 2d 50 (1984). The 1985 amendment, however, added a requirement that the disability interfere with the employee’s ability to perform available work. See 1985 N.C. Sess. Laws, chapter 653, section 1. Subsection (e) now requires a causal link between the disability and the ability to perform available work. Here, the evidence establishes a causal link only between the injury and the failure to perform. Plaintiff *353produced sufficient evidence from the two employers he has worked for since leaving defendants’ employ to show that his permanent partial disability does not interfere with his ability to adequately perform work substantially identical to work he was employed to do for defendants. In addition, as we have already noted, there is some evidence that at the time in question defendant had easier work available which plaintiff might have been able to perform without the trouble he experienced on his assigned routes to California and the northeast. Defendants failed to present a sufficient forecast of evidence to sustain summary judgment based on either G.S. 97-6.1(c) or (e).
 Plaintiff also contends the trial court erred in granting summary judgment for defendants on his second claim for relief. His complaint alleged that defendants wrongfully discharged him for refusing to drive under unsafe conditions. Citing Sides v. Duke University, 74 N.C. App. 331, 328 S.E. 2d 818, disc. rev. denied, 314 N.C. 331, 333 S.E. 2d 490 (1985), plaintiff argues his second claim for relief states a legally recognized cause of action on which there are genuine issues of material fact for trial. We disagree.
In Sides, this court created an exception to the common law employment “at will” doctrine. Sides held that a cause of action existed for “wrongful discharge” of an employee at will who was fired in retaliation for her refusal to give false or incomplete testimony in a medical malpractice case. In Walker v. Westinghouse Electric Corp., 77 N.C. App. 253, 335 S.E. 2d 79 (1985), however, this court declined to establish a general cause of action for wrongful discharge of an employee fired for raising safety concerns related to his employment. Instead, we held without deciding whether such a cause of action existed, that the plaintiff in Walker had failed to present a sufficient forecast of evidence to justify denial of the defendant’s motion for summary judgment. *354material fact on defendants’ motive under G.S. 97-6.1, we find nothing in the record to indicate that defendants’ motive was that plaintiff raised “safety concerns” about his employment.
In fact, plaintiffs allegations for wrongful discharge do not rest on his having raised safety concerns, but rather on his failure to do an unsafe act. We hold that plaintiff has no cause of action for discharge from failure to perform an act which he may be able to prove was unsafe. Our decision in Sides v. Duke University, supra, was based on the employer’s willful violation of clearly expressed public policy. To allow an action for “wrongful discharge” where the employer’s discharge of the employee was for a failure to perform an “unsafe” act is entirely different. As we noted in Walker v. Westinghouse Electric Corp., supra, “some jobs are by their very nature dangerous.” Id. at 263, 335 S.E. 2d at 86. Holding that every discharge for failure to perform an allegedly unsafe task is actionable, would create a prolific and unwarranted source of trouble in the workplace. The kind of overriding policy concerns present in Sides are simply not present here.
 Plaintiff has also raised, for the first time on appeal, the argument that a federal regulation prohibits defendants from firing him for his refusal to drive when his physical condition was so impaired. See 49 C.F.R., section 392.3 (1986) and 49 U.S.C.A., section 2305 (Supp. 1987). Plaintiff contends that defendants failed to comply with the regulation and therefore, under Hogan v. Forsyth County Country Club Co., 79 N.C. App. 483, 340 S.E. 2d 116, disc. rev. denied, 317 N.C. 334, 346 S.E. 2d 140-141 (1986), defendants are liable for wrongful discharge. In Hogan, the court explained Sides as recognizing an exception to the employment at will doctrine in favor of an employee who is discharged in retaliation for (1) his refusal to do an act prohibited by law, or (2) his performing an act required by law. Hogan at 498, 340 S.E. 2d at 126. Therefore, even assuming that the issue is properly before us, we find no authority for, and decline to adopt, plaintiffs argument that violation of a federal regulation creates an exception to the employment at will doctrine in North Carolina.
Reversed in part, affirmed in part.
Judges Martin and Parker concur.
Judge MARTIN concurred in this opinion prior to 31 December 1987.