OPINION OF THE COURT
Gulotta, J.On this appeal we are called upon to interpret the recently enacted class action statute CPLR article 9 (L 1975, ch 207). The underlying action sounds in products liability and involves an intrauterine device (IUD) known as the Daikon Shield. The device was manufactured by defendant, A. H. Robins Co., Inc. (A. H. Robins), between 1970 and 1975. Plaintiff, a former user of the Daikon Shield, alleges that the IUD was defectively designed and that it caused her injury. She further alleges that the defendant breached certain express and implied warranties with regard to the Daikon Shield. Plaintiff seeks damages on behalf of herself and the class she purports to represent, which class is defined as those New York women who suffered "pelvic infection, uterine abscessing *13and/or perforation, and related or incidental hemorrhaging” as a consequence of their use of the Daikon Shield.
Special Term denied plaintiffs application for class action certification, whereupon the instant appeal was taken. The order appealed from should be affirmed.
THE FACTS
The defendant began marketing the Daikon Shield during November of 1970, after purchasing the rights to the product in June of 1970 from the Daikon Corporation which had developed the device. A Daikon Shield could only be obtained through a licensed physician, who would normally explain to the patient the advantages and disadvantages of using the IUD prior to her making a decision. If the patient then chose to have a Daikon Shield inserted, the physician would perform certain fitting procedures and insert the device. Product brochures issued by A. H. Robins were distributed to users through their physicians.
As part of its program for marketing the Daikon Shield, A. H. Robins advertised intensively in medical journals and, in addition thereto, the inventor of the Daikon Shield, Dr. Hugh J. Davis, undertook to explain the advantages of his IUD in a series of articles which were also published in medical journals. By 1974 the Daikon Shield was being used by approximately 2.2 million women in the United States, many of whom reside in New York. At that time, however, a series of medical studies began to appear which indicated that the Daikon Shield was unsafe and ineffective and that it had resulted in an increased incidence of pelvic infection among large numbers of women. Following public criticism and an investigation by the Federal Food and Drug Administration, A. H. Robins permanently suspended distribution of the Daikon Shield in January, 1975.
Thereafter, more than 670 products liability actions were commenced nationwide against A. H. Robins, more than 150 of those being brought in the Federal courts. Pursuant to section 1407 of title 28 of the United States Code, the Federal actions were consolidated for the purpose of conducting joint, pretrial proceedings (Matter of Robins Co. "Daikon Shield” IUD Prods. Liab. Litigation, 406 F Supp 540 [Jud Pan Mult Lit, 1975]). The Federal panel had concluded (p 542) that joint discovery would be advantageous because of the "commonality of factual issues concerning the design, testing, manufacture, labeling *14and inspection of the Daikon Shield.” Many of the State plaintiffs co-operated in this joint Federal discovery, under the leadership of a noted New York attorney, Paul D. Rheingold, the "trustee” of the Daikon Shield group.
The instant litigation is one of 72 similar actions which have been brought in the New York State courts. Plaintiff suggests, however, that the majority of the prospective plaintiffs have yet to commence any action and estimates that the proposed class she purports to represent may include as many as 2,525 New York women. Plaintiff’s bill of particulars alleges that the Daikon Shield was manufactured without adequate control over the production process and specifies three particular design defects which she contends resulted in pelvic disease, pelvic infection, uterine perforation and other injuries to its users.1
On application by the plaintiff for class action certification, the appropriateness of a class action was considered by Madam Justice Burstein at Special Term. She found that to determine the issue of liability as to individual class members would require an inquiry "into the facts and circumstances of each individual case” and, ultimately, that as many as 4,000 additional parties (including physicians and hospitals) would have to be joined. She therefore concluded that plaintiff’s purported class failed to satisfy two of the requirements for a class action set forth in CPLR 901:
"2. [that] there are questions of law or fact common to the class which predominate over any questions affecting only individual members; [and]
* * *
"5. [that] a class action is superior to other available methods for the fair and efficient adjudication of the controversy.”
As a consequence, class action certification was denied.
THE LAW
This court has never before been called upon to consider the applicability of our revised class action statute in a products liability case.
Our new statute, enacted in 1975, was patterned after rule 23 of the Federal Rules of Civil Procedure and, while the legislative history of our own statute is virtually silent upon *15this point, it is clear that the framers of Federal rule 23, as amended in 1966, considered class action treatment to be particularly inappropriate in the case of a mass tort or "mass accident” resulting in injuries to numerous persons. (See Advisory Committee Note to the 1966 revision of rule 23, 39 FED 69, 98.) The commentators, however, have been virtually unanimous in suggesting that the Advisory Committee took an unduly restrictive view of the possibilities of class action treatment in such cases (see, e.g., 3B Moore’s Federal Practice, par 23.45 [3], p 23-811, n 35; 7A Wright and Miller, Federal Practice and Procedure, § 1783, pp 116-118), and have indicated time and again that such treatment can and should be considered in an appropriate case. Similar views have been expressed by the commentators on our own article 9 (see McLaughlin, Practice Commentaries, McKinney’s Cons Laws of NY, Book 7B, CPLR 901:6, p 327; Siegel, New York Practice, § 142, pp 182-183). The thrust of all of these authors is substantially the same, namely, that in a mass tort or mass accident situation, such as a major airplane crash or train wreck, the courts should seriously consider isolating the issue of liability for class action treatment, while allowing the individual determinations on damages to be tried separately thereafter (see CPLR 906). There are, however, important differences between mass torts of the type referred to above and product liability cases such as the case at bar, particularly insofar as the question of causality is concerned. Thus, in the typical mass tort situation, proximate cause can usually be determined on a class-wide basis, since the "cause” of the common disaster will always be identical as to each of the plaintiffs, while contributory negligence on the part of an individual plaintiff is virtually nonexistent.
More directly in point on the present question, two well-known tort attorneys and authors who presently represent a number of Daikon Shield plaintiffs have considered the feasibility of class action treatment in the products liability area and have been less than enthusiastic in their conclusions. Thus, Alfred S. Julien, who represents plaintiffs in 10 of the New York Daikon Shield cases, has been critical of the restrictive views taken by the New York Courts in class action cases decided under the prior law (see NYLJ, May 31, 1972, p 1, col 1), but has concluded that personal injury (as opposed to property damage) product liability cases are not amenable to class action treatment in view of the "[d]ifficult questions of *16causation and [the] extent of injury” which they present (NYLJ, May 31, 1972, p 6, col 4). The views of Paul D. Rheingold, the trustee of the Daikon Shield group and counsel for four of the New York plaintiffs, are also pertinent here. Under current law, he has written, "it seems probable that class actions cannot be maintained in products cases involving personal injuries” (3A Frumer and Friedman, Products Liability, § 46A.02[4], p 16A-35). More recently, however, Mr. Rheingold has suggested that the courts "may have adopted too restrictive a view of the role of class action treatment” (3 A.B.A., Litigation, No. 3 [Spring, 1977], pp 18, 21), and has cited with approval the comments of Professor Moore, arguing that there is "much to commend the use of class actions in certain types of mass disaster cases” (id., p 21 [emphasis supplied]).
We emphatically agree with our dissenting brother that, although our own statute was patterned after Federal rule 23, we are not constrained to follow the restrictive views of the Federal courts (or the Federal Advisory Committee), on the problem at issue. Indeed, were this a case where the liability issue could be isolated and treated on a class-wide basis (e.g., a typical common disaster or mass tort case), there would be strong reasons for certifying the proposed class, although the question of damage would necessarily have to be left for individual determination. Thus, in the case of an airplane crash, to use the most frequently cited example, it would be possible in many cases to isolate a single causative factor which was responsible for the injury or death of all of the class members. It is clear, however, that in the instant action liability cannot be determined with regard to the entire class. Admittedly, it would be possible to determine several important factual issues on a class basis, including (1) the existence of a defect or defects in the Daikon Shield, (2) the nature of the representations and warranties made with respect to the device and (3) whether the warranties and representations were false. But assuming, arguendo, that these issues were to be decided in plaintiffs’ favor, individual determinations would still be required on several "key” issues, among them (1) whether the injuries to individual class members were, in fact, caused by the defect or defects and (2) whether the individual class members detrimentally relied on the false representations or warranties. Moreover, defendant has raised as affirmative defenses the Statute of Limitations and contributory *17negligence on the part of the user, neither of which can be determined on a class-wide basis.2
The difficulties involved in determining the causality in injuries of this sort cannot be overstated. For example, in Vincent v Thompson (50 AD2d 211), this court considered the case of a child who had become ill following the administration of a vaccine known as Quadrigen. An earlier Federal decision had established that the Quadrigen vaccine was, in fact, defective, resulting in serious injuries to the plaintiff in that case. In Vincent, plaintiff sought to invoke the doctrine of collateral estoppel based on the Federal decision, but, in an opinion by Mr. Justice Shapiro, we rejected plaintiff’s argument noting, inter alia, that her symptoms had differed from those of the plaintiff in the earlier action. Since it was not apparent that the plaintiff’s injury was caused by the defective drug, the issues in the two cases were not identical and collateral estoppel could not properly be invoked.
The same considerations militate against class action treatment in the case at bar. Assuming, for the sake of argument, that in the instant litigation it were to be proved that the Daikon Shield had been defectively designed, it could not be inferred therefrom that each and every woman who suffered pelvic or uterine injury following the use of the Daikon Shield suffered that injury as a result of her use of said shield. The injuries may have resulted from a variety of factors completely unrelated to the use of the Daikon Shield, including, perhaps, the peculiarities of her individual physique or the negligent conduct of the user or her physician. The complexities of the causality problem are highlighted by a recent nisi prius decision in California concerning a Daikon Shield action. In Askeland v Robins Co. (Super Ct, Cal, No. 330633, filed Feb. 7, 1978), the court found, after a lengthy trial, that there were factors in plaintiff’s background which created a risk, of pelvic infection and concluded that plaintiff had not proved that the Daikon Shield was the cause of her injury. The Askeland decision thus illustrates the importance of determining causality on a case-by-case basis.
*18Equally difficult problems arise when plaintiffs breach of warranty claims are considered. According to plaintiffs bill of particulars, defendant’s express warranties consisted mainly of advertisements in the various medical journals. Moreover, the factual issues are complicated by the fact that different types of advertisements were printed at various times in various journals. Finally, the representations were not, by and large, made directly to members of the proposed class, but rather to their physicians.
In order to prevail in an action based on representations made in advertising, a plaintiff must prove knowledge of, and reliance upon, the representations alleged (Randy Knitwear v American Cyanamid Co., 11 NY2d 5, 12; Strauss v Long Is. Sports, 60 AD2d 501). Although it has been suggested that a court could determine, on a class-wide basis, whether a given warranty has been breached, leaving the question of reliance and damages to be determined in individual lawsuits (cf. Siegel, New York Practice, § 142, p 182), this court has only recently warned of the difficulties inherent in such an approach and has rejected it (Strauss v Long Is. Sports, supra). As the court (per Mr. Justice Margett) observed in Strauss (60 AD2d 506-507):
"It is true that the language of CPLR 901 (subd a, par 2), which requires that questions of law or fact common to the class must predominate over 'any questions affecting only individual members’, clearly indicates an intent that the mere existence of individual questions should not defeat the granting of class status (see 2 Weinstein-Korn-Miller, NY Civ Prac, par 901.08, p 9-31). We are fully aware of the courts’ power to sever certain issues while permitting others to be tried as class actions (CPLR 906) and are cognizant of the fact that some commentators have suggested that questions of reliance —particularly in fraud cases—be so severed (see 2 Weinstein-Korn-Miller, NY Civ Prac, par 901.08, p 9-33; see, also, 3B Moore’s Fed Prac, par 23.45[2], pp 23-762—23-763). The basic theory behind such severance is that judicial economy might be served by trying common questions in one action (2 Weinstein-Korn-Miller, NY Civ Prac, par 901.08, p 9-33).
"While laudable in theory, the practicality of such severance has been questioned where [as here] individual reliance would not be 'substantially established by the very nature of the proofs on the issue of liability’ (Morris v Burchard, 51 FRD 530, 536 [SD NY]; see, also, Tober v Charnita, Inc., 58 *19FRD 74, 84-85 [MD Pa]; Hoffman v Charnita, Inc., 58 FRD 86, 91 [MD Pa]). Certainly, in a case where common exposure to— or reliance upon—alleged misleading advertising cannot be readily inferred, there is no advantage to be gained from permitting the action to proceed as a class action since the proceeding is likely to 'splinter into individual trials’ (Comment, Litigating the Antitrust Conspiracy Under Amended Rule 23, 54 Va L Rev 314, 318).”
In Strauss, a New York Nets season ticket holder sought to recover the cost of his tickets because the Nets had traded the team’s superstar, Julius Erving (Dr. J.) prior to the opening of the 1976-1977 NBA season. Strauss alleged that in deciding to purchase their tickets, he and others had relied on Nets’ advertising touting Dr. J. Strauss sought an order declaring his action to be a proper class action on behalf of Nets season ticket holders who had purchased their tickets for the 1976-1977 season subsequent to the first-advertised presence of Julius Erving, but prior to the first public announcement that Erving had been traded, and who bought their tickets, at least in part, because of their expectation that Julius Erving would be playing for the Nets if not injured. We held (reversing Special Term) that neither a class action, nor a partial class action, would be appropriate in that case, stating, inter alia (p 507):
"The papers in the record indicate that prior to June 30, 1976, over 2,622 Nets season tickets had been sold. These represented over half of the tickets sold for the entire season. Yet prior to June 30, 1976, newspaper advertising had been published only between June 18 and June 23. The only other advertising before September 19, 1976 was on one day, July 18, 1976. Between July 18, 1976 and September 19, 1976, a period during which there was no newspaper advertising for the Nets’ tickets, 761 tickets were sold. On September 21, 1976 Erving first announced that he would not appear at training camp. Thereafter, another 276 tickets were sold.
"Obviously, different factors were at work in each of those periods affecting the motivation of ticket purchasers. Ticket purchasers may have been motivated by the fact that the Nets had won the American Basketball Association championship, or by the fact that they had been admitted to the National Basketball Association and would be playing all of the established teams. Business reasons may have been the dominant motive for the purchases, or the geographical location of the *20team may have figured into the decision (pro basketball enthusiasts in Nassau County might have been inclined to buy season tickets to the Nets games rather than travel to Manhattan to see the Knickerbockers). In short, by no stretch of the imagination may one comfortably presume that a majority of season ticket holders purchased in reliance on the Nets’ newspaper advertising. Indeed, many season ticket holders may not have even seen defendant’s advertisements (see Edelman v Lee Optical Co., 24 111 App 2d 216).”
Also relevant to this discussion is the opinion of the Appellate Division, First Judicial Department, in Ross v Amrep Corp. (57 AD2d 99), in which the plaintiff sought to certify as a class persons who had relied upon various false representations in purchasing land from the defendant. The court (per Mr. Justice Silverman) noted, inter alia (p 103), that "the falsity of each of these representations is a common question with respect to those purchasers to whom the particular misrepresentation was made. But we do not think that on this complaint those common questions can fairly be said to predominate” (emphasis supplied).
In view of the complicated issues of fact which must be resolved on an individual basis, it is our opinion that common questions of law and fact do not predominate in this action and that Special Term correctly denied plaintiff’s motion for class action certification. Nor do we find this to be a proper case for a partial class action certification pursuant to CPLR 906. While some factual issues could perhaps be resolved in a class action format, these issues are thoroughly intertwined with those which must be determined individually. Furthermore, in view of the limited scope of the issues which can be resolved on a class-wide basis, the judicial economy to be reaped and the advantages for litigants of a partial class action will be relatively small. It should be noted, in this regard, that many Daikon Shield plaintiffs will not be required to bear the full expense of litigating their claims on an individual basis. Some have already taken advantage of the joint discovery in the consolidated Federal pretrial proceedings by joining the "Daikon Shield” group,3 while others, *21perhaps, will be able to invoke the doctrine of collateral estoppel, and thus be spared the expense of relitigating previously decided issues (but, see, Vincent v Thompson, 50 AD2d 211, supra).
Accordingly, the order appealed from should be affirmed.
. See the dissenting opinion of Shapiro, J., at p 24, infra.
. A related issue not raised in the present action, where the attending physician has not been joined, but likely to be present in a number of other actions which have already been commenced and which would be included within the proposed class, is the question of possible negligence on the part of the user’s doctor in fitting and inserting the device, instructing her on its use, diagnosing possible health problems during their early stages and other related matters.
. The Daikon Shield group is a voluntary association of plaintiffs’ attorneys which was organized in 1974 when the number of Daikon Shield cases pending around the country became apparent. Mr. Rheingold, the trustee of the group, has described its activities as follows (3 A.B.A. Litigation, No. 3 [Spring, 1977], 18-19):
"Members joining the Daikon Shield group pay $200 and receive a background *21package of data containing sample pleadings, answered interrogatories, medical articles, and governmental publications. They also receive periodic newsletters covering trials, settlements, new medical and administrative developments, group dealings with defense counsel, and the availability of experts. * * *
"About 250 lawyers or law firms are currently participating in the Daikon Shield group’s activities. They come from forty-six states and Canada, and together represent perhaps 500 plaintiff's. * * *
"One outstanding feature of the Daikon Shield group has been its arrangement with national counsel for the manufacturer to hold one set of depositions and documentary discovery and to apply that discovery package to all participating cases, even those filed after the agreement was reached. These arrangements grew out of an initial contract in 1975 between the trustee of the plaintiffs’ group and the national counsel for the defendant manufacturer. After numerous drafts, revisions and meetings, the parties finally signed an agreement in June, 1976, covering many pretrial matters.
"The discovery plan, which runs seventeen single-spaced pages, provides for three types of discovery by the plaintiff’s group: (1) inspection of the defendant’s files (more than 100,000 documents) and copying of pertinent records (reduced to a 'trustee’s package,’ the documents in the package are marked by the defendant, making a copy an 'original’ for trial purposes); (2) a master set of interrogatories; (3) depositions of many employees of the defendant and a limited number of other persons, including the inventors and investigators. Many provisions of the Federal Rules of Civil Procedure and the Federal Rules of Evidence have been incorporated into the plan, even though the plan applies primarily to State court cases.
"This discovery, when done, will apply to every Daikon Shield case then participating in or afterward added to the plan. Each participating case will be assessed its proportionate share of the total costs of discovery, including the time of the attorney who takes the discovery for the group. The current rough estimate of the per-case cost is less than $500.”