consideration of defendants’ awareness of possible dangers to users of their product applies only to a determination of liability for punitive damages.
An award of punitive damages “is calculated to punish wrongful conduct.” Palmer v. A.H. Robins Co., 684 P.2d 187 (Colo. 1984). Thus, the focus in determining punitive damages shifts from the product to the conduct. Therefore, the court correctly limited defendants’ testimony concerning their knowledge of the relationship between asbestos dust and lung disease to the issue of punitive damages.
B.
Defendants next contend that the trial court’s refusal to give CJI-Civ.Sd 14:24 (1989) denied them the opportunity to present a state-of-the-art defense, with resulting prejudice.
The Notes on Use following the requested instruction state:
“This instruction should not be given unless there is sufficient evidence for a reasonable jury to find the basic facts giving rise to the presumption.”
Therefore, in order for the instruction to be given, there must be sufficient evidence that the best technical, mechanical, and scientific knowledge and methods available prior to the sale of their product had been utilized by defendants.
Here, the uncontradicted evidence supports the trial court’s implied determination that defendants had available to them scientific knowledge of the possible dangers of their product to those who installed it, especially if done in a restricted environment. Consequently, the instruction was properly refused.
III.
Defendants next assert that the trial court abused its discretion in the assessment of costs. We agree.
Plaintiff submitted bills of costs totaling approximately $26,700. The trial court reduced this amount to approximately $20,-750. In doing so, the trial court made no findings, only stating that it was “making a slight reduction in plaintiff’s bill of costs. Total amount of the costs are $20,754.77. They are added to the judgment.”
In response to defendants’ request that the court “make a record as to what’s being reduced and what is not,” the court replied, “I have reduced some of the plaintiff’s expert costs by $5,600.” When asked the reason for the reduction, the court replied, “Not reasonable.”
Defendants acknowledge that an award of costs lies within the discretion of the trial court, subject to statutory parameters. Section 13-16-122, C.R.S. (1987 Repl.Yol. 6A); Rossmiller v. Romero, 625 P.2d 1029 (Colo.1981). However, the awarding of expert witness fees is not without limits but is “circumscribed by the rule of reason, viz., sound judicial discretion.” Leadville Water Co. v. Parkville Water District, 164 Colo. 362, 436 P.2d 659 (1967).
Here, the plaintiff requested a “lump sum” figure for the trial testimony of each of several witnesses. No documentation indicating a reasonable basis upon which these sums were calculated was submitted by plaintiff, nor were the actual sums expended for the witnesses’ services shown.
In addition to the fees for expert testimony, plaintiff’s bills of costs included deposition costs and “general expenses.” It is unclear whether the court found these costs reasonable or which, if any, were disallowed.
Defendants argue that certain costs requested for expert witnesses were unjustified; plaintiff speculates in reply as to which costs were excluded by the trial court. The record before us is not sufficient to determine which costs were allowed and whether they were reasonable and permitted by statute. Therefore, the cause must be remanded to the trial court for findings which will establish the costs to be paid by defendants and the basis upon which the court arrived at its determination of the reasonableness of those costs.
In making these findings, the court must specify which expenses are allowed in light of § 13-16-112, C.R.S. (1987 Repl.Vol. 6A) (limit of four witnesses unless necessity for