The instant appeal requires us once again to reaffirm the sharp distinction which the courts of this Commonwealth have drawn between negligence suits and products liability actions based on section 402A of the Restatement (Second) of Torts. We hold that the trial court may not invite the jury to consider the reasonableness of the defendant’s conduct by instructing on the “state of the art defense.”
Appellant Fletcher Carrecter Jr. appeals from a judgment in favor of appellee Colson 1 entered on a jury verdict in a products liability action based upon an injury allegedly caused by a Colson Model 6055 drum truck. A drum truck is a type of hand truck specially adapted for use in moving large drums or barrels. The drum truck was manually operated by sliding forks on the bottom of the truck under a barrel, tilting the truck upward, sliding a hook-like clasp over the upper edge of the barrel, and then pulling the truck handles backward so that the barrel rested on the truck and could be rolled.
Carrecter was employed as a general laborer at Acme Hardesty Company (whiсh is not a party to the instant litigation). Three to five days each month, Carrecter’s work assignment involved lifting, moving and “palletizing” 2 450-pound barrels using a drum truck of a type manufactured and sold by Colson between 1937 and 1957. While performing these tasks on February 14, 1977, Carrecter sustained baсk injuries which he attributed to his having pulled the Colson drum truck handles backwards in order to move a barrel.
In his products liability suit against Colson, Carrecter introduced evidence tending to show that the Colson drum truck, while being used to transport. weights within the *99 stated capacity of its wheels, 3 imposed forces on the user’s spine greater than the human spine can safely support. Carrecter therefore argued that the truck was defective either because it was designed in a manner which subjected the user’s spine to excessive force or because Colson did not warn of the maximum load capacity at which the truck could be maneuvered without placing undue stress on the user’s back. Carrecter also adduced evidence linking his back injury to his use of the Colson truck.
In its answers to written interrogatories, the jury found that the Colson drum truck was not dеfective due to its design or lack of accompanying warnings, and a verdict was entered in favor of Colson. Carrecter’s post-trial motions for judgment n.o.v. or a new trial were denied. Judgment for Colson was entered and this appeal followed.
Appellant argues that the trial judge erred in charging the jury that it could consider the engineering know-how available to Colson at the time the truck was manufactured in determining whether the truck was defective. 4 The trial court first instructed the jury that if at the time the drum truck was manufactured and left the сontrol of Colson it “lacked any element necessary to make it safe for the use or contained any condition that made it unsafe for the use that it was intended for, then the product may be considered by you as defective and [Colson] liable for the harm caused,” and that “[a] product which is designed in a manner which makes it unsafe for its intended use is defective, even though it perfectly conforms to its intended design.” N.T. 8.19-8.20. However, the trial judge added *100 that in assessing the alleged defectiveness of the drum truck, the jury also “must consider the engineering knowledge and the know how that was generally available to the manufacturer, Colson, at the time [the drum truck] was manufactured.” N.T. 8.20 (emphasis added). The judge reiterated that the jury “must consider whether it was defectively designed at the time it was manufactured ... considering the engineering knowledge and know how which a manufacturer then should have. ” N.T. 8.21 (emphasis added). 5
We agree that it was error to instruct the jury to consider the level of engineering know-how available to Colson in determining whether the drum truck was defective. This case was submitted to the jury on a products liability theory. In a products liability аction the plaintiff need not prove negligence on the part of the manufacturer. The plaintiff must establish only that the product was defective and that the defect caused, i.e. was a substantial factor in bringing about, the harm suffered by the plaintiff.
Sherk v. Daisy-Heddon,
*101
The difficulty with the latter portion of the charge inviting the jury to consider the “state of the art”
6
is that it injects negligence principles into a products liability case. In a products liability action negligence is not an element of the plaintiff's case, nor is the defendant’s lack of negligence a defense. In
Azzarello
our Supreme Court was faced with the question whether it was proper to instruct the jury that it must find the defendant’s product “unreasonably dangerous.” The court held that the jury should not be instructed in such terms, concluding instead that the words “unreasonably dangerous” were no more than a label to be used where it is determined that the risk of loss should be placed on the supplier.
7
the “reasonable man” standard has no place in a strict liability case ... To charge the jury or permit argument concerning the reasonableness of a consumer’s or seller’s actions and knowledge, even if merely to define “defective condition” undermines the policy considerations that *102 have led us to hold in Salvador [v. Atlantic Steel Boiler Co.,457 Pa. 24 ,319 A.2d 903 (1974) ]. that the manufacturer is effectively the guaranter [sic ] of his product’s ' safety.
The holdings of
Berkebile
and
Azzarello
were reaffirmed by this Court in
Dambacher v. Mallis,
Examining the court’s charge in light of the foregoing principles it is clear that the charge had the impermissible effect of setting up Colson’s non-negligence as a defense. By instructing the jury that it should take into consideration the engineering know-how “generally available” to Colson or alternatively the knowledge which Colson “should have” had when the drum truck was manufactured, the court caused the jury to focus on the reasonableness of the defendant’s conduct rather than on the safety of the product. What a dеfendant “should have known” is a *103 classic negligence inquiry which our courts have held unequivocally does not belong in a products liability action. The jury found against the plaintiff Carrecter, and its verdict clearly could have been influenced by the improper chargе, under which the jury could have found Colson not liable even if the drum truck was in fact not safe for its intended use. Therefore, a new trial is required.
We are aware that in
Dambacher
the majority expressly reserved judgment on whether any special problems were posed by the use of the “state of the art” defense in inadequate warning cases, because no “state of the art” issues were raised in
Dambacher. See id.,
336 Pa.Superior Ct. at n. 9,
As further support for this conclusion, we note that even before
Azzarello,
this Court held in a products liability
*104
action grounded in part on inadequate warnings that
“A
seller must give such warnings and instructions as are required to inform the user of the possible risks and inherent limitations of the product____ This is so regardless of whether the seller knew or had reason to know of the risks and limitations.”
Pegg v. General Motors Corp.,
In his appeal, Carrecter has additionally raised several other bases for a new trial: (1) that the jury verdict contravened the weight of the evidence on the drum truck’s safety; (2) that the expert testimony of Carrecter’s witness, Dr. Simon, was improperly excluded; (3) that the trial judge exceeded the bounds of impartiality by interrogating Carrecter’s witnesses; (4) that somе jury instructions misrepresented the facts adduced at trial; and (5) that the trial judge did not solicit a general verdict. Since our review of the defective product charge compels us to order a new trial, we deem it unnecessary at this time to consider the othеr claims raised by Carrecter. 10
Judgment reversed and case remanded for a new trial. Jurisdiction is relinquished.
Notes
. At trial, Carrecter was the plaintiff, and Colson Equipment Division and the Marmon Group, Inc., were the defendants. For the purposes of this appeal, both defendants аre appellees and will be collectively referred to as "Colson."
. This maneuver required Carrecter to tilt the drum truck up onto a four or five inch high forklift pallet and release the drum so it rested on the pallet.
. Evidence at trial indicated that the rated capacity of the Model 6055 drum truck in Colson’s sales literature was 800 pounds. Colson’s witnesses explained that this figure represented the capacity of the wheels, which were the weakest part of the truck, and that the loads borne by the user’s body did not enter into this cаlculation.
. Carrecter further argues that it was error for the court not to instruct the jury that the fact that the Colson drum truck was essentially similar to all others produced in the industry at the time was not a defense. We are inclined to agree but it is unnecessary to reach this issue because we find that the instructions which were given were erroneous.
. In context, the court’s instructions on "engineering know how” were more closely tied to the defective design issue than the warnings issue. However, the trial judge mentioned the inadequate warnings claim both before (at N.T. 8.20) and after (at N.T. 8.22) the state of the art charge, and did not suggest to the jury that it was not relevant to the warnings issue. Therefore, we will consider the propriety of the charge with respect to both the design and warning claims.
. The term “state of the art” has been given a variety of meanings, including (1) industry custom,
e.g. Sturm, Ruger & Co. v. Day,
. When a products liability claim is pleaded the trial judge makes a threshold determination whether as a matter of social policy the case is appropriate for treatment under the rubric of products liability. In making this determination the judge acts as a combination social philosopher and risk-utility economic analyst; for a more detailed explanation of the factors to be considered,
see Azzarello; Dambacher;
and
Lobianco v. Property Protection, Inc.,
. We prefer the terminology "inadequate warnings" to "failure to warn” because the latter language suggests a breach of a duty in a way which tends to connote negligence.
. See supra note 6.
. Carrecter further аlleges on appeal that the trial court erred by not entering a judgment n.o.v. on the basis that the evidence of record unequivocally established that the Colson drum truck was defective. In reviewing the denial of a judgment n.o.v., this Court examines the evidence and all reasonable inferences therefrom in the light most favorable to the verdict winner.
Burch v. Sears, Roebuck and Co.,