102 Wn.2d 581 (1984) 689 P.2d 368

RITA RENE MARTIN, ET AL, Appellants,
v.
ABBOTT LABORATORIES, ET AL, Respondents.

No. 49359-6.

The Supreme Court of Washington, En Banc.

October 4, 1984.

*582 Manza, Moceri, Gustafson & Messina, P.S., by Michael S. Manza, John S. Glassman, and John L. Messina, for appellants.

Reed, McClure, Moceri & Thonn, P.S., by Hugh McClure, and Keating, Bucklin & McCormack, by Jane E. Gilbertsen, for respondents Abbott Laboratories, et al.

Helsell, Fetterman, Martin, Todd & Hokanson, by William A. Helsell and Karen J. Vanderlaan (Crosby, Heafey, Roach & May, by Richard J. Heafey and Peter W. Davis, of counsel), for respondent Eli Lilly.

Williams, Lanza, Kastner & Gibbs, by Joseph J. Lanza, Douglas A. Hofmann, and Karen J. Feyerherm, for respondent E.R. Squibb & Sons.

Richard J. Dunlap and R. Scott Fallon, for respondent Kirkman Laboratories.

Schwabe, Williamson, Wyatt, Moore & Roberts, by Frank W. Draper and Elizabeth K. Reeve, for respondents Merck and Co., et al.

Bradford M. Gierke and Sandra Bobrick (of Gierke, Curwen, Metzler & Bobrick), for respondent Raway Pharmaceutical Co.

F. Lee Campbell and David D. Swartling (of Karr, Tuttle, Koch, Campbell, Mawer & Morrow, P.S.), for respondent Rexall Drug Co.

*583 Gordon, Thomas, Honeywell, Malanca, Peterson & O'Hern, by Mark G. Honeywell, for respondent Stanlabs Pharmaceutical Co.

Mullin, Etter & Cronin, P.S., by Ronald K. Mullin, for respondent Upjohn Co.

Hackett, Beecher, Hart, Branom, Vavricheck & Drury, by John A. Drury, for respondents Ludwig, et al.

Tewell, Thorpe & Findlay, Inc., P.S., Duane Tewell, and Paul F. Cane, for respondents Breon Laboratories and Winthrop Laboratories.

Williams, Lanza, Kastner & Gibbs, by Mary H. Spillane and Don T. Mohlman, for respondents Ayerst Laboratories and Wyeth Laboratories.

Bogle & Gates, Ronald T. Schaps, and William G. Clark, for respondent Armour Pharmaceutical Co.

DORE, J.

This case concerns whether plaintiffs, allegedly injured by the drug diethylstilbestrol (DES), have a cause of action against numerous DES manufacturers when they cannot identify the specific manufacturer of the DES ingested. The trial court held that plaintiffs had stated a cause of action when it denied summary judgment as to two drug manufacturers, finding material issues of fact under a theory of alternate liability.

We reject the application of alternate liability. We hold that plaintiffs have stated a cause of action under a theory of recovery announced in this opinion. For the reasons discussed below, we affirm in part and reverse in part.

TRIAL COURT PROCEEDINGS

Rita Rene Martin was born on October 4, 1962. Her mother, Shirley Ann Martin, obtained a prescription for and ingested DES from May 1962 until the date Rita Martin was born. On January 4, 1980, Rita was diagnosed as suffering from clear cell adenocarcinoma of the vagina. On February 21, 1980, as a result of the cancer, Rita underwent *584 a radical hysterectomy, pelvic node dissection, and partial vaginectomy.

Like many other women who have pursued judicial remedies for injuries they allege were caused by DES, Shirley Martin cannot remember which drug company manufactured the DES she ingested. Moreover, because of the passage of time and because DES was marketed generically, neither Shirley's physician nor her pharmacist, William Ludwig, Jr., f/d/b/a Lakewood Pharmacy, Inc., can remember which company manufactured or marketed the drug Shirley ingested. The only thing Shirley Martin can substantiate is that she took the drug in 100 mg. doses.

Shirley and Rita Martin sued numerous drug companies on the theories of negligence, strict liability and breach of warranty, for personal injuries, pain, suffering, and destruction of the parent-child relationship.^[1] The Martins alleged that all of the pharmaceutical companies were liable for their injuries because of the companies' concerted or joint action to gain FDA approval and to market DES. The Martins allege this concerted action is established by (1) the manufacturers' collaboration in testing and marketing DES, (2) the marketing of DES on a mutually agreed-upon formula, and (3) the marketing of DES as a fungible item which led to the selling of DES without reference to the brand prescribed.

The Martins also sued pharmacist Ludwig on the theory of strict products liability for selling an unreasonably dangerous product.

Defendants Summers Laboratories, Inc., and Hill Pharmaceutical, Inc., were dismissed by stipulation. Corvit *585 Pharmaceuticals was never served with process and is not a party to this appeal. Penn Herb Company, Ltd., was dismissed when it became apparent that it was not a proper defendant. Approved Pharmaceutical Corporation and Pharmex, Inc., are in default because they were served but never appeared to defend.

The remaining defendants moved for summary judgment, generally alleging that the Martins' inability to identify the correct manufacturer of the drug Shirley Martin ingested was fatal to the Martins' cause of action. The trial judge granted summary judgment to all of the remaining defendants except Stanley Drug Products, Inc., Kirkman Laboratories, Inc., and pharmacist Ludwig.

The trial judge dismissed defendants who had proved they did not market DES in the dosage or form ingested by Shirley Martin, which included Abbott Laboratories; Carnrick Laboratories, Inc.; Eli Lilly and Company; Merck and Company, Inc.; Rexall Drug Company; The Upjohn Company; and Raway Pharmaceutical Company. The trial judge further dismissed those defendants who had proved that they did not market DES for accidents of pregnancy, which included Armour Pharmaceutical Company; Ayerst Laboratories, Inc.; Wyeth Laboratories, Inc.; Breon Laboratories, Inc.; and Winthrop Laboratories. Summers Laboratories, Inc., was dismissed, as the product they manufactured was not marketed in the state of Washington. E.R. Squibb and Sons, Inc., was dismissed on the basis that the retail price charged Shirley Martin for DES purchased from Ludwig's pharmacy was less than the wholesale price for Squibb's trademark DES. Stanlabs Pharmaceutical Company was dismissed upon a finding that no material issue of fact existed as to successor liability for the acts of Stanley Drug Products, Inc.

As to the two remaining defendants, the trial judge held that, under the theory of "alternate liability", there were material issues of fact as to the liability of Stanley Drug Products, Inc., and Kirkman Laboratories, Inc.

Although the trial judge found that there were arguable *586 questions of fact concerning liability for concerted action, the trial judge rejected this theory because it would result in joint and several liability for a number of defendants who could prove that they did not manufacture the DES that caused plaintiffs' harm, and because he believed the theory of "alternate liability" more fairly accommodated the facts of this case.

The trial court also found material issues of fact as to Ludwig's liability as the dispensing pharmacist. Finding no just reason for delay, the trial court entered a final judgment pursuant to CR 54(b).

The Martins filed a notice of appeal in this court on March 1, 1983. At the same time, Stanlabs Pharmaceutical Company, Kirkman Laboratories, Inc., and Ludwig filed notices of appeal in Division Two of the Court of Appeals. Both appeals are now consolidated for review here.

The Martins endorse the trial court's ruling, but continue to argue that they have raised issues of fact which would justify even broader liability under concerted action, enterprise, or market-share theories of liability. They urge this court to reverse the trial court's order as to those respondents dismissed on summary judgment. The respondents argue that the trial court correctly dismissed the majority of the pharmaceutical companies joined in this action. Respondents contend, among other things, that adoption of any theory that would impose industry-wide liability would hamper the development of new drugs, would impose enormous potential costs on pharmaceutical companies, and would not serve as an incentive to use greater care in producing drugs. Finally, respondents urge the Martins to seek broader liability through legislative enactment.

Stanley Drug Products, Inc., and Kirkman Laboratories, Inc., contend that the trial judge erred in not granting summary judgment in their favor. Their basic contentions are that neither was identified as the actual defendant that manufactured or distributed the DES ingested by Shirley Martin, and the probability that either was such party is *587 very small, in that they are but two manufacturers from a large potential number of defendants.

DEVELOPMENT AND MARKETING OF DES

Crucial to an understanding of this litigation and resolution of the issues is the history of the development and marketing of DES. Much of the history is developed in the record here, and detailed in numerous reported cases and law journals.^[2]

Estrogen is a female sex hormone present in varying amounts in the body of every woman. This hormone is crucial to female sexual development and fertility. Natural estrogens were first isolated outside the human body in the 1920's. Doctors initially used the hormone to treat menopausal symptoms in women. Natural estrogen therapy, however, had several drawbacks. The process of isolating the hormone was very costly. Furthermore, natural estrogens could only be administered through injections into the buttocks, often resulting in painful abscesses.

In the late 1930's, a group of British scientists discovered DES, a synthetic compound which shares some of the characteristics of estrogen. DES could be produced at a fraction of the cost of isolating natural estrogens and could be orally administered. It was never patented.

Approval of the Food and Drug Administration (FDA) was required before DES could be marketed in the United States. Pursuant to the Federal Food, Drug, and Cosmetic Act, 52 Stat. 1040 (1938), each company wishing to market DES had to file a New Drug Application (NDA) detailing the proposed uses of the drug, clinical data establishing its safety and efficacy, the drug's chemical composition, methods *588 of manufacturing it and proposed labeling.

The first NDA for DES was filed in 1939. By the end of 1940, ten firms had applied. The NDAs sought authorization to market and distribute DES for four purposes: the treatment of postmenopausal symptoms, senile vaginitis, gonorrheal vaginitis, and suppression of lactation. None of the proposed uses relate to problems of pregnancy.

All indications from the FDA in 1939 suggested that the FDA would review each manufacturer's NDA separately. This meant that each firm had to stand on the clinical data it submitted in its own NDA.

In late 1940, the FDA indicated that it was considering requesting the drug companies to pool their clinical data on DES. On December 20, 1940, the FDA convened a meeting with the drug companies, at which it formally requested that the companies submit their clinical data jointly in a "master file". The FDA believed that the individual NDAs did not contain sufficient clinical data to properly evaluate the safety and efficacy of DES. Pooling of the data, in the FDA's view, would eliminate this problem as well as expedite its evaluation of DES.

The FDA made three other requests of the drug companies at this time. The first was that each company use the same United States pharmacopeia standard to establish the chemical identity of the drug. The second was that they develop uniform labeling regarding the indications for use of the drug and recommended dosage. The third was that they place a provision in their NDAs authorizing the FDA to use the materials gathered by each firm in considering any other NDAs that might be filed. The companies, for the most part, complied with these additional requests.

A "small committee" of representatives of those firms which had filed NDAs coordinated the pooling of clinical data and submitted the "master file" to the FDA. The FDA approved the marketing of DES for uses unrelated to problems of pregnancy in late 1941. Thereafter, the "small committee" was disbanded.

Experimental use of DES as a miscarriage preventative *589 began in the early 1940's. Several drug companies supplied DES to independent researchers for such experimentation. The drug companies also sent representatives to medical conferences on this topic.

The first supplemental NDAs for the use of DES as a miscarriage preventative were filed in 1947. Only a few companies conducted their own experiments to establish the safety and efficacy of DES for this purpose. Among these, none tested DES on pregnant laboratory animals. The applicants relied instead upon published studies done by independent researchers at medical schools to support their applications. The supplemental NDAs did not refer to the "master file" of clinical data that had been submitted with the 1941 NDAs. The FDA's policy in reviewing supplemental NDAs, however, was to take into consideration all of the material that it had in support of the original NDAs.

The FDA began approving the supplemental NDAs in July 1947. Soon thereafter, DES was marketed as a miscarriage preventative. Some companies marketed the drug under a trade name; others marketed it generically. Several companies supplied DES to competitors. Because the DES compounds produced by the drug companies were chemically identical, pharmacists often filled prescriptions for DES with whatever company's drug was in stock, a practice that the firms were aware of. None of the companies warned physicians about the possibility of carcinogenic or other risks to the offspring of women who took DES.

The number of firms marketing DES has fluctuated considerably over the years. Estimates are that up to 200 or 300 companies manufactured and marketed DES between 1947 and 1971.

In 1952, the FDA decided that DES was no longer a "new drug" within the meaning of the Federal Food, Drug, and Cosmetic Act. This meant that companies wishing to market DES for the first time would not have to file NDAs.

In 1971, Dr. Arthur Herbst and several other physicians published a study linking the outbreak in young women *590 of clear cell adenocarcinoma, a form of cancer, with the ingestion of DES by their mothers during pregnancy. In November of that same year, the FDA required the drug companies to include a statement on all labels that "DES is contraindicated for use in the prevention of miscarriages." Today, the FDA continues to permit the use of DES in treatments unrelated to problems of pregnancy.

IDENTIFICATION OF CULPABLE DEFENDANT

Traditional products liability theory has always required a reasonable connection between the injured plaintiff, the injury-causing product, and the manufacturer of the injury-causing product. "An essential element of the plaintiff's cause of action for negligence, or for that matter for any other tort, is that there be some reasonable connection between the act or omission of the defendant and the damage which the plaintiff has suffered." W. Prosser, Torts § 41, at 236 (4th ed. 1971) (hereinafter cited as Prosser).

The majority of the courts in DES litigation have followed the traditional approach, finding no cause of action when the plaintiff cannot identify the particular manufacturer of the pills which caused her injury. See Gray v. United States, 445 F. Supp. 337 (S.D. Tex. 1978); Namm v. Charles E. Frosst & Co., 178 N.J. Super. 19, 427 A.2d 1121 (1981); Ryan v. Eli Lilly & Co., 514 F. Supp. 1004 (D.S.C. 1981); Mizell v. Eli Lilly & Co., 526 F. Supp. 589 (D.S.C. 1981); Morton v. Abbott Labs., 538 F. Supp. 593 (M.D. Fla. 1982); Pipon v. Burroughs-Wellcome Co., 532 F. Supp. 637 (D.N.J. 1982); Tidler v. Eli Lilly & Co., 95 F.R.D. 332 (D.D.C. 1982); Payton v. Abbott Labs, 386 Mass. 540, 437 N.E.2d 171 (1982).

Notwithstanding this general rule, four theories have been proposed, and in some cases adopted, to give DES plaintiffs a cause of action. These theories are (1) alternate liability, (2) concerted action, (3) enterprise liability, and (4) market-share liability. See generally Note, Market Share Liability: An Answer to the DES Causation Problem, 94 Harv. L. Rev. 668 (1981).

*591 ALTERNATE LIABILITY

Alternate liability arose as a cure for plaintiff causation problems. Prosser, at 243. The theory was introduced in Summers v. Tice, 33 Cal.2d 80, 199 P.2d 1, 5 A.L.R.2d 91 (1948) and incorporated in Restatement (Second) of Torts § 433B(3), at 441-42 (1965):

Where the conduct of two or more actors is tortious, and it is proved that harm has been caused to the plaintiff by only one of them, but there is uncertainty as to which one has caused it, the burden is upon each such actor to prove that he has not caused the harm.

In its classic application, the theory requires each hunter who negligently shot at plaintiff to prove that his bullet did not cause the injury. Failing such proof, both are liable. Summers, at 88.

The rule of Summers requires that in cases where all defendants are equally culpable, and their negligence precludes an innocent plaintiff from identifying them, basic considerations of fairness demand that the burden of proof shift from plaintiff to defendant. Defendants unable to meet the burden of proof are found jointly and severally liable.

Alternate liability has been recognized, but not as of yet applied in this state. See Clift v. Nelson, 25 Wn. App. 607, 608 P.2d 647, review denied, 93 Wn.2d 1030 (1980); Phennah v. Whalen, 28 Wn. App. 19, 621 P.2d 1304 (1980), review denied, 95 Wn.2d 1026 (1981). In Clift, the court held that alternate liability was inapplicable because the plaintiff could not establish that all named defendants had been tortious and the possibility that the tortious act was committed by a party not named as a defendant.

Several DES cases have discussed alternate liability as a means of providing DES plaintiffs with a cause of action.

In Abel v. Eli Lilly & Co., 418 Mich. 311, 343 N.W.2d 164 (1984), the trial court denied the plaintiffs a cause of action for failing to identify which of the named defendants had manufactured the specific harmful product. The two theories argued on appeal were concerted action and alternate *592 liability. The basis of the alternate liability theory was that all defendants acted wrongfully in producing and marketing a defective product, and that each plaintiff was injured by the product of one of the several defendants. The plaintiffs argued that because all defendants acted wrongfully, even though only one actually caused the injury, all should be jointly and severally liable just as were the hunters in Summers. Recognizing that the plaintiffs faced an enormous burden of proof as well as the problem of apportionment of damages if they were to prevail, the Michigan court nevertheless allowed the cause of action to proceed. Its decision was premised on the expressed policy of favoring an innocent plaintiff over a wrongdoer when injustice was inevitable. As distinguished from other DES litigation where the theory of alternate liability had been asserted, the plaintiffs in Abel alleged that they had named all the known manufacturers of DES whose products were distributed during the relevant time period, and that one or more of the named defendants had caused the harm. Abel, 343 N.W.2d at 174. This allegation that all the defendants were before the court most likely facilitated the court's acceptance of the alternate liability theory as sufficient to state a cause of action.

A showing that all possible tortfeasors are before the court was not required, however, in one DES case. A New Jersey superior court, in Ferrigno v. Eli Lilly & Co., 175 N.J. Super. 551, 420 A.2d 1305 (1980), interpreted existing New Jersey law to allow the plaintiffs to proceed on a theory of alternate liability despite a failure to show that all potential defendants were before the court. The court held that under existing New Jersey law a plaintiff's cause of action survives an inability to identify the precise causative agent and the possibility that the precise causative agent is not among the defendants before the court. Ferrigno, at 567. The court also proposed strong policy reasons to justify allowing the suit to proceed, one of which was the favoring of recovery by innocently injured plaintiffs over allegedly culpable defendants. If the DES plaintiff proved *593 her allegations, it reasoned, none of the defendants could be considered truly innocent. The judge also relied on the New Jersey "single indivisible injury" rule, which essentially tolerates the possibility that "one wrongdoer can escape liability altogether while another tortfeasor may be compelled to pay more than his actual share of the damages ..." Ferrigno, at 570. The decision did, however, enumerate specific methods by which a defendant in a DES case could exculpate itself. Among the methods enumerated were: identification of the actual manufacturer; proof that defendant company never manufactured the drug involved; proof that defendant did not manufacture DES until after the plaintiff's birth; proof that the product never reached the outlet where the plaintiff's mother purchased the DES; or proof that defendant never manufactured a drug of the physical description indicated by the plaintiff. Ferrigno, at 571-72. In conclusion, the court in Ferrigno found that existing New Jersey precedent allowed acceptance of the theory of alternate liability in DES cases where the defendant cannot be identified or may not actually be before the court.

In contrast to Ferrigno, other courts have not recognized the alternate liability theory. The New Jersey Superior Court, appellate division, in Namm v. Charles E. Frosst & Co., 178 N.J. Super. 19, 427 A.2d 1121 (1981), rejected the reasoning of the lower court in Ferrigno and dismissed the claim before it on the ground that it was possible that the company which had actually made the particular injury-causing DES had not even been named as a defendant. The court went on to say that to apply the alternate liability theory would result in the taking of the property of all the named defendants in order to pay for harm which may have been caused by only one of the defendants or even by one who is not a party to the lawsuit, who is unknown to the defendants, over whom they have no control or even any meaningful contact. Namm, at 33. The court indicated that any departure from traditional concepts and basic principles of tort law should be undertaken by the court of *594 last resort and not by the appellate division.

The California Supreme Court in Sindell v. Abbott Labs., 26 Cal.3d 588, 607 P.2d 924, 163 Cal. Rptr. 132, cert. denied, 449 U.S. 912 (1980), held that the traditional alternate liability theory of Summers, as incorporated in the Restatement (Second) of Torts § 433B(3) (1965), could not be employed to hold drug manufacturers liable in DES actions where all possible defendants were not before the court. Sindell, at 602-03. Accord, Pipon v. Burroughs-Wellcome Co., 532 F. Supp. 637, 638-39 (D.N.J. 1982); Ryan v. Eli Lilly & Co., 514 F. Supp. 1004, 1016 (D.S.C. 1981); Morton v. Abbott Labs., 538 F. Supp. 593, 598-99 (M.D. Fla. 1982).

The Wisconsin Supreme Court in Collins v. Eli Lilly Co., 116 Wis.2d 166, 342 N.W.2d 37, cert. denied, ___ U.S. ___, 83 L.Ed.2d 51, 105 S.Ct. 107 (1984) rejected the traditional alternate liability theory because it contemplated that all possible defendants be before the court. Collins, at 183-84. The court did, however, adopt a "risk contribution" theory which may be considered a modification of alternate liability. The court held that the plaintiff need commence suit against only one defendant and allege the following elements:

[1] that the plaintiff's mother took DES; [2] that DES caused the plaintiff's subsequent injuries; [3] that the defendant produced or marketed the type of DES taken by the plaintiff's mother; [4] and that the defendant's conduct in producing or marketing the DES constituted a breach of a legally recognized duty to the plaintiff. In the situation where the plaintiff cannot allege and prove what type of DES the mother took, as to the third element the plaintiff need only allege and prove that the defendant drug company produced or marketed the drug DES for use in preventing miscarriages during pregnancy.

Collins, at 193-94. The court fashioned this remedy on the grounds that as between an innocent plaintiff and the defendants, who may have provided the product and all who contributed to the risk of injury to the public, the *595 interests of justice and fundamental fairness demand that the latter should bear the cost of injury. Collins, at 191. The court further held that the defendants may implead third party defendants, and defendants have the burden of proving that they did not produce or market the subject DES, either during the time period the plaintiff was exposed to DES or in the relevant geographic market area. The plaintiff is entitled to recover all damages from the one defendant, or in the situation where there are multiple defendants, plaintiff should recover from each their proportionate share of liability under principles of comparative negligence. Collins, at 193-200.

In sum, the short history of DES litigation shows that the alternate liability theory is not accepted in those jurisdictions which follow the traditional rules of products liability. Those courts demand that a defendant, that is, the manufacturer or distributor of the drug, be identified as the causal agent for plaintiff's injury. Although some courts have found this theory applicable, they have done so under only two conditions: (1) where the plaintiff can show all of the defendants were before the court, or (2) where not all of the defendants were joined but strong policy reasons and the "single indivisible injury" or "risk contribution" rules could be applied.

We find persuasive the commentators and courts that have concluded that strict application of alternate liability theory does not present a viable theory for DES cases. The alternate liability theory formulation contemplates that all tortious defendants will be joined in the suit. Thus, the court can be sure that at least one of the defendants was directly responsible for the plaintiff's harm. The alternate liability formula does not, in its pure form, provide a fair way to apportion damages among the defendants. Under the alternate liability theory, defendants that produced or marketed small amounts of DES and those that produced or marketed large amounts would be equally liable.

*596 CONCERTED ACTION

The theory of concerted action derives from vicarious liability. The plaintiff must show a tacit agreement among defendants to perform a tortious act. Prosser, at 291-92. The Restatement requires a showing that a defendant

(a) does a tortious act in concert with the other or pursuant to a common design with him, or

(b) knows that the other's conduct constitutes a breach of duty and gives substantial assistance or encouragement to the other so to conduct himself, or

(c) gives substantial assistance to the other in accomplishing a tortious result and his own conduct, separately considered, constitutes a breach of duty to the third person.

Restatement (Second) of Torts § 876(a)-(c), at 315 (1977). The basic difference between alternate liability and concerted action is that the former involves independent acts by two or more tortfeasors, all of whom have acted wrongfully, but only one of whom has injured the plaintiff, whereas concert of action is a true joint tort in that all acted jointly to produce the harm. Abel v. Eli Lilly & Co., 418 Mich. 311, 343 N.W.2d 164, 176 (1984).

The concerted action typically alleged by DES plaintiffs (and the Martins in this case) consists of the pharmaceutical manufacturers using one another's marketing techniques, manufacturing DES according to an agreed-upon formula, promoting its marketability as a generic drug, relying upon one another's testing, and encouraging one another not to perform adequate tests and not to provide adequate warnings. Note, Market Share Liability: An Answer to the DES Causation Problem, 94 Harv. L. Rev., at 670 n. 18.

The Abel court accepted this theory, holding that defendants' joint breach of their duty of care to the plaintiffs resulted from their concerted action in producing and marketing an ineffective and dangerous product without adequate testing or warning. The defendants contended that there was no evidence of concerted action, but the court determined that this was a disputed question of fact, *597 not a test of the sufficiency of the pleadings. The court did not indicate in its opinion, however, just what would constitute sufficient proof of concerted action.

In Bichler v. Eli Lilly & Co., 55 N.Y.2d 571, 436 N.E.2d 182, 450 N.Y.S.2d 776 (1982), the court allowed a limited expansion of the doctrine of concerted action to cover the type of circumstances faced in a DES case. The concerted activity claimed was essentially the same as in Abel, the wrongful testing and marketing of the drug for treatment of problems of pregnancy. The plaintiffs, however, specifically contended that the drug companies paralleled each other in failing to test DES properly as a result of some implied understanding. The court viewed concert of action as being analogous to a "joint control of the risk" as discussed in the case of Hall v. E.I. Du Pont De Nemours & Co., 345 F. Supp. 353, 372 (E.D.N.Y. 1972). This control, the court reasoned, could be shown by evidence of explicit agreement, or by parallel behavior from which tacit agreement sufficient to sustain the concerted action theory could be inferred.

All other courts, however, have rejected, as a matter of law, DES plaintiffs' claims that the pharmaceutical manufacturers engaged in concerted action. These courts have generally rejected this theory because the plaintiff cannot show an agreement among the manufacturers to market the drug in 1947 for accidents of pregnancy. Although the court in Ferrigno accepted the alternate liability theory, it rejected the plaintiff's concert of action theory. The reasoning behind the rejection was the distinction made between the 1940 and 1947 applications to the FDA to market DES. The plaintiffs relied on the 1940 applications to establish concert of action, but because those applications were unrelated to DES use in pregnancy, the Ferrigno court refused to consider them as evidence of concerted, tortious activity. The court also emphasized the necessity of alleging that the concerted conduct itself was tortious.

Just as the California Supreme Court in Sindell rejected the opinion of the appellate court regarding alternate liability, *598 it similarly refused to apply that court's interpretation of concert of action to a DES claim. The appellate court had determined that plaintiff's allegations satisfied the pleading requirements under the concert of action theory. It found that the fact that every defendant in the case may not have manufactured the particular pills taken by the mother was not determinative, since the pleadings indicated that each defendant gave substantial assistance or encouragement to the tortious conduct of the others. The appellate court also stated that the determination of whether the defendants' conduct was a substantial factor would be a jury question. The truth of the allegations or their proof was said not to be a matter of concern at that stage of the pleadings. Therefore, the appellate court concluded that identification of the actual manufacturer was also irrelevant.

The California Supreme Court's analysis, however, found that there was no concert of action among defendants within the meaning of that doctrine. The court held that the plaintiff's allegations did not amount to a charge of tacit understanding or a common plan because the parallel or imitative conduct in reliance on each other's testing and promotional methods was a common practice in the industry, and insufficient to support the allegations. The court would require the plaintiff to prove that each defendant knew the other's conduct was tortious and that the manufacturers encouraged one another to refrain from testing DES. Sindell, at 604-06. Accord, Collins, at 185-87; Ryan, at 1015-16; Morton, at 597; Lyons v. Premo Pharmaceutical Labs, Inc., 170 N.J. Super. 183, 190, 406 A.2d 185, cert. denied, 82 N.J. 267 (1979).

We agree with those jurisdictions which have rejected the concerted action theory as a basis of liability in DES cases. Several of the opinions rejecting the concert of action theory disclose a conscientious, careful analysis of the applicable rules of law in the light of a sensitive and understanding discussion of the realities of the problems presented by the DES cases. The pleadings and supporting *599 affidavits do not support the theory that the defendants tacitly agreed to produce and market DES for accidents of pregnancy without adequately testing the drug or warning of its potential dangers. Although there was a substantial amount of parallel activity by the defendants, this does not rise to the level of concerted action.

ENTERPRISE LIABILITY

The theory of enterprise or industry-wide liability is grounded on the premise that "losses to society created or caused by an enterprise or, more simply, by an activity, ought to be borne by that enterprise or activity." Klemme, The Enterprise Liability Theory of Torts, 47 U. Colo. L. Rev. 153, 158 (1976). Enterprise liability holds the defendants liable for sharing in industry-wide misconduct. See, e.g., Hall v. E.I. Du Pont De Nemours & Co., 345 F. Supp. 353 (E.D.N.Y. 1972). In Hall, the plaintiffs, children who were injured by blasting caps, could not identify the manufacturers of the caps that injured them. The court held plaintiffs' claims contained issues of fact regarding whether the blasting cap manufacturers were jointly aware of the risks at issue and had a joint capacity to reduce those risks. Hall, at 380. At present, the theory of enterprise liability has not been accepted by any court involved in DES litigation. The courts have generally rejected this theory on the grounds that enterprise liability, as described in Hall, is predicated upon industry-wide cooperation of a much greater degree than occurred among DES manufacturers. Morton, at 598;