UNITED STATES DISTRICT COURT

DISTRICT OF NEW HAMPSHIRE

Joseph N. Masello

v. Civil No. 08-cv-136-JL

Opinion No. 2011 DNH 061

The Stanley Works, Inc.

and ZAG Industries, Ltd.

MEMORANDUM ORDER

The parties to this wrongful death action arising from the

collapse of a plastic stepstool have challenged the admissibility

of each other’s proffered expert testimony. The stepstool was

manufactured by defendant ZAG Industries, Ltd. and allegedly

distributed by or on behalf of defendant The Stanley Works, Inc. 

The stool collapsed as Joseph M. Masello was standing on it while

restocking products during an overnight shift at the store where

he worked, the Christmas Tree Shops location in Salem, New

Hampshire. Masello fell backward and struck his head against the

floor, sustaining an injury that caused him to fall into a coma

that night and to die two weeks later.

Masello’s son has brought this action in his capacity as the

administrator of the estates of both his father and his mother,

Masello’s wife, who was alive at the time of Masello’s death but

has since died of unrelated causes. The complaint asserts 1

For clarity’s sake, the court will use “Masello” to refer 1

to the father and “the plaintiff” to refer to the son in his

capacity here.

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 1 of 16
state-law claims of negligent design and failure to warn, strict

products liability, and breach of warranty against both

defendants. This court has diversity jurisdiction over this

action between the plaintiff--who, acting on behalf of decedents

who were New Hampshire citizens when they died, is treated as a

New Hampshire citizen, see 28 U.S.C. § 1331(c)(2)--and the

defendants, which are a Connecticut corporation and an Israeli

corporation. See id. § 1332(a)(3). 

To support his claims at trial, the plaintiff intends to

rely on the expert testimony of Myer Ezrin, a plastics engineer. 

Ezrin plans to testify that the stool failed when one of its

front legs cracked, beginning at the point where the leg

connected to a rib on the underside of the bottom step, and that

this occurred largely because the rib and the leg were designed

to meet at a sharp corner, rather than a rounded one. The

defendants have moved to preclude Ezrin from offering these

opinions, arguing that they are “the product of speculation” and

therefore inadmissible. The defendants have also moved for

summary judgment, see Fed. R. Civ. P. 56, arguing that, without

the challenged opinion testimony, the plaintiff has no proof that

any defect in the stool caused Masello’s fatal injury.

For his part, the plaintiff has moved to preclude one of the

defendants’ designated experts, Miki Birnbaum, from opining that

the stool “was reasonably designed and was fit for its ordinary

2

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 2 of 16
and reasonably foreseeable uses.” The plaintiff argues that

Birnbaum, who works as an engineer for ZAG, lacks the

qualifications necessary to give this opinion, that the opinion

lacks sufficient support, and that, in any event, it is

cumulative of the testimony anticipated from another of the

defendants’ designated experts.

As fully explained below, the parties’ motions to exclude

each others’ experts’ opinions are denied, because they rely on

alleged deficiencies that go to the weight, rather than the

admissibility, of those opinions. It follows that the

defendants’ motion for summary judgment, which is based solely on

the claimed inadmissibility of Ezrin’s opinions, is also denied.2

I. Applicable legal standard 

“The touchstone for the admission of expert testimony in

federal court litigation is Federal Rule of Evidence 702.” Crowe

v. Marchand, 506 F.3d 13, 17 (1st Cir. 2007). Under that rule,

If scientific, technical, or other specialized

knowledge will assist the trier of fact to understand

the evidence or to determine a fact in issue, a witness

qualified as an expert by knowledge, skill, experience,

training, or education, may testify thereto in the form

While this court ordinarily holds oral argument on all 2

dispositive motions, counsel indicated during a recent telephone

conference with the court that they saw no need for that approach

in this instance.

3

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 3 of 16
of an opinion or otherwise, if (1) the testimony is

based upon sufficient facts or data, (2) the testimony

is the product of reliable principles and methods, and

(3) the witness has applied the principles and methods

reliably to the facts of the case.

Fed. R. Evid. 702. As the structure of this rule suggests,

before the factfinder in a case can consider expert testimony

over the adverse party’s objection, the trial judge, serving as

“gatekeeper,” must determine whether the testimony satisfies the

relevant foundational requirements. See Daubert v. Merrell Dow

Pharms., Inc., 509 U.S. 579, 597 (1993). While the party seeking

to introduce the testimony bears the burden of proving its

admissibility, id. at 592, the burden is not especially onerous,

because “Rule 702 has been interpreted liberally in favor of the

admission of expert testimony.” Levin v. Dalva Bros., Inc., 459

F.3d 68, 78 (1st Cir. 2006).

II. Background

The body of the Handy 2-Step stool consists of a single

piece of molded polypropylene plastic. As its name suggests, the

Handy 2-Step has two steps, connected by four legs. Each of the

legs ends in an outward pointing “toe” with a rubber tip on the

bottom. The underside of each of the steps consists of a number

of supporting ribs running in a perpendicular direction from the

center to the front or back side of the step. The bottom edge of

4

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 4 of 16
each of the intersections between a rib and the front side of the

step is rounded so that the rib meets the step at a radius of 5

millimeters. There are also two ribs, running parallel to the

bottom step, that connect it to the inside of each of the front

legs. The bottom edges of these ribs are not rounded. 

3

In Masello’s accident, the left front leg of the stool

cracked into several pieces, causing it to collapse. One of

Masello’s fellow employees subsequently retrieved the stool and

three broken pieces of the left front leg, but was unable to

locate the toe. The parties disagree over whether the toe broke

off in the accident and could not be found afterwards or whether

the toe had already broken off before Masello stepped on the

stool that night. An inspection of the stool after the accident 4

The defendants state that each of these edges actually has 3

a radius of 0.5 mm, but explain that they have assumed, for

purposes of their motion to exclude Ezrin’s testimony, that the

edge has no radius.

The evidence on this point supports conflicting inferences. 4

On the one hand, the defendants emphasize that other Christmas

Tree Shops employees could not locate the missing piece, despite

a dedicated search of the area, and that a post-accident

inspection of the stool revealed that pieces had broken off other

legs as well. On the other hand, the plaintiff emphasizes that

the floors of the store were cleaned just hours after the

accident occurred, and that a Christmas Tree Shops employee

testified that she inspected all of the stools before Masello’s

shift that night and did not notice that any of them were broken.

5

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 5 of 16
revealed a crack running upward from the intersection of the rib

connecting the broken leg to the bottom step. 

III. Analysis

A. The defendants’ motion to preclude Ezrin’s testimony

Ezrin holds an undergraduate degree in chemistry from Tufts

and a doctorate in organic chemistry from Yale. Before his

retirement in 2006, he worked as a plastics engineer for some 55

years, roughly half of it for private companies, including Dupont

and Monsanto, and the other half of it in academia, where he was

affiliated with the Institute of Materials Science at the

University of Connecticut. He has published a full-length book

and numerous articles on plastics failure.

As noted briefly at the outset, Ezrin plans to testify that

Fracture of the front leg, supporting one side of the

lower step of the stool, was due, in large part, to

stress applied in service at a point where a rib, fused

to an inner part of the leg, had sharp corners in the

rib. In good design of plastic parts it is well known

that the structure of high stress points should not

have sharp corners and particularly be supported by

only one rib. These focus applied stress over a small

area, increasing the likelihood of fracture. Good

design calls for ribs to have a curved, i.e., radiused,

connection to the part. That way stress is distributed

over a larger area.

Citing four separate published articles, Ezrin explains that

“problems caused by sharp corners, including fracture, have been

6

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 6 of 16
well known for years” in the field of plastics design. Ezrin

also relies on an internal 1997 memorandum by a ZAG engineer

about the design of the Handy 2-Step. The memorandum states, in

relevant part, “This is of most importance--we need all the

connecting points of ribs to body to be with a radius of 5 mm so

it will not break at these points.” The defendants nevertheless

challenge Ezrin’s opinion that, as predicted by ZAG’s engineer,

the stepstool’s front leg did indeed break at the point where it

met the rib, and did so due largely to the lack of a radius.

First, the defendants argue that, even if it is “conceded”

that “a sharp corner is more susceptible to fracture than a

corner with a radius” (which is not much of a concession in light

of the identical opinion expressed by ZAG’s own engineer in the

1997 memo), Ezrin still “makes an illogical leap from his belief

that the rib juncture could have been stronger with a radiused

corner to his belief that the rib juncture was the location of

failure.” But there is nothing “illogical” in the notion that a

product has broken in the place where, as Ezrin explains, plastic

objects are “well known”--and well documented--to break. As the

Supreme Court has observed, “no one denies that an expert might

draw a conclusion from a set of observations based on extensive

and specialized experience.” Kumho Tire Co. v. Carmichael, 526

U.S. 137, 156 (1999).

7

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 7 of 16
The defendants do not take issue with Ezrin’s assertion that

sharp corners in plastic design are commonly the source of

fracture. Of course, it does not necessarily follow from that

proposition alone that the sharp corner between the left front

leg and the supporting rib was the source of the fracture here,

but Rule 702 does not limit qualified experts to “unassailable”

conclusions, just “‘methodologically reliable’” ones. United

States v. Mahone, 453 F.3d 68, 72 n.1 (1st Cir. 2006) (quoting

Ruiz-Troche v. Pepsi Cola of P.R. Bottling Co., 161 F.3d 77, 85

(1st Cir. 1998)). Ezrin’s conclusion that a plastic object broke

where plastic objects are generally known and documented to break

cannot be dismissed as “unreliable” and therefore inadmissible

under Rule 702--at least without some indication that “reliable

principles and methods” of plastics engineering exclude this sort

of commonsense reasoning.

The defendants have provided no such indication, whether in

the form of an opinion from their own retained expert, an

industry publication, or otherwise. Instead, they argue that

Ezrin “ignores any other location on the left front leg as a

potential location of the fracture initiation,” particularly “the

missing piece of the leg (the toe).” But Rule 702 “does not

require an expert to take into account every possible factor when

giving an opinion.” 3 Louis R. Frumer & Melvin I. Friedman,

8

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 8 of 16
Products Liability § 18A.04[6][e], at 18A-80.11-12 (1960 & 2010

supp). So Ezrin’s “failure” to account for the possibility that

the toe was missing before Masello used the stool is no basis for

disallowing his testimony.

In any event, there is conflicting evidence as to whether

the toe from the left front leg was in fact missing before

Masello stood on the stool, or went missing when the stool

fractured. See note 4 and accompanying text, supra. Resolving

these conflicts, and assessing the credibility of any expert who

has done the same in reaching his opinions, are tasks for the

jury. See, e.g., Crowe, 506 F.3d at 18; Newell P.R., Ltd. v.

Rubbermaid, Inc., 20 F.3d 15, 20 (1st Cir. 1994). 

Second, the defendants argue that, even if Ezrin has

correctly identified the sharp corner between the rib and the leg

as the source of the fracture, he did “not use a reliable

methodology to conclude that the lack of radius [there] caused

the crack.” Ezrin concludes that “[a] contributor to fracture

was that the rib with sharp corners was at or very near the high

applied stress point” where the leg meets the step, deviating

from “well known guidelines of good design of plastics.” He

further explains that it is “well known” that sharp corners

“focus applied stress over a small area, increasing the

9

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 9 of 16
likelihood of fracture,” while a rounded corner reduces that

likelihood by distributing the stress over a larger area.

Like Ezrin’s opinion as to where the fracture started, then,

his opinion as to why it started is based on the “well known”

principle that sharp corners in plastic objects tend to break

more than rounded corners. The defendants do not question this

principle and, indeed ZAG’s own engineer specifically recommended

that the Handy 2-Step have rounded corners at “the connecting

points of ribs to body . . . so it will not break at these

points” (emphasis added). Contrary to the position the

defendants have now taken, the notion that, when a product lacked

a feature generally recognized to prevent it from breaking, it

was the lack of that feature that caused the product to break,

cannot properly be characterized as “speculative.” Cf. Sikora v.

AFD Indus., 221 F. Supp. 2d 920, 923 (N.D. Ill. 2002) (admitting,

in products liability case, expert’s opinion “formed by comparing

the evidence before him [about the product] with the knowledge he

has gathered working in the [relevant] industry”).

The defendants emphasize that Ezrin made no calculations as

to the amount of stress placed on the junction of the left front

leg and its supporting rib when Masello stood on the stool.5

With his objection to the defendants’ motion to exclude 5

Ezrin’s testimony, the plaintiff filed a supplementation, dated

10

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 10 of 16
But, again, the defendants have not come forward with anything

suggesting that this calculation is an essential part of any

reliable methodology for determining why a plastic object failed.

If the lack of such calculations indeed call Ezrin’s opinion into

question, the defendants can make that point through crossexamination at trial. Their motion to preclude him from

testifying is denied.

B. The plaintiff’s motion to exclude Birnbaum’s testimony

The plaintiff, for his part, has moved to preclude one of

the defendants’ designated experts, Miki Birnbaum, from offering

expert opinion at trial that the Handy 2-Step “was reasonably

designed and was fit for its ordinary and reasonably foreseeable

uses.” The plaintiff argues that (1) Birnbaum is not qualified

to give that opinion, (2) it is “not supported by any scientific

journals or literature,” and (3) it is cumulative of the opinion

February 17, 2011, offering Ezrin’s calculation of the stress

applied to the left front leg of the stool when Masello stood on

it, and concluding that the figure was “an extraordinary [sic]

high amount of stress which is why the leg fractured and

collapsed.” In their reply, the defendants object to this

supplementation as “too late and unfairly prejudicial,” noting

that it was produced well beyond the deadlines for expert

supplementations and depositions, and the day before the summary

judgment deadline. Because the court rules that Ezrin’s opinions

are admissible even without the supplementation, there is no need

to consider at this point whether its late disclosure prevents

the plaintiff from relying on the supplementation at trial. 

11

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 11 of 16
testimony expected from another of the defendants’ designated

experts. None of these arguments suffices to prevent Birnbaum

from offering his opinion as to the design of the stepstool.

First, Birnbaum has a bachelor’s degree in mechanical

engineering, and has worked as ZAG’s engineer in charge of

testing its plastic products for the past 15 or so years. As

Masello emphasizes, Birnbaum has no education or experience in

designing plastic products, for ZAG or anyone else (before

working there, he held jobs designing automatic process machines

and testing cars for handicapped drivers), and--unlike Ezrin--

“has never published any literature, written any articles, taught

a class, or hosted a seminar on plastics or design.”

In the court’s view, however, this lack of experience in

plastics design does not disqualify Birnbaum from giving the

challenged opinion, in light of the nature of the opinion itself. 

“Whether a witness is qualified can only be determined by the

nature of the opinion he offers.” Gladhill v. Gen. Motors Corp.,

743 F.2d 1049, 1052 (4th Cir. 1984). In concluding that the

Handy 2-Step “was reasonably designed and was fit for its

ordinary and reasonably foreseeable uses,” Birnbaum does not

purport to rely on any design expertise. Instead, he relies on

the results of product testing in which, among other things, the

stool “withstood a 1,200 pound load,” which is “far beyond any

12

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 12 of 16
load the stool would reasonably be expected to see in real life.” 

Birnbaum has spent the last 15 years testing ZAG’s plastic

products to determine whether they will hold up under everyday

use. This experience qualifies him to opine on whether, based on

such testing, the Handy 2-Step was in fact “reasonably designed

and was fit for its ordinary and reasonably foreseeable uses.”6

As the court of appeals has explained, “an expert need not have

design experience with the particular product in order to render

expert opinion about the []reasonableness of its design.” Tokio

Marine & Fire Ins. Co. v. Grove Mfg. Co., 958 F.2d 1169, 1175

(1st Cir. 1992).

Second, as this court has explained, Rule 702 does not

require an expert to buttress his testimony with references to

published materials. See Warford v. Indus. Power Sys., 2008 DNH

105, 10-11. Instead, whether a theory “‘has been subjected to

peer review and publication,’” while relevant in determining the

admissibility of expert testimony under some circumstances, “may

This does not rule on whether Birnbaum is qualified to 6

testify to everything set forth in his expert report, e.g., his

opinions that the sharp corners where the front legs met their

supporting ribs “did not play any role in this accident,” which

occurred because “the left front leg was missing a piece,

including the rubber tip” so it “had nothing to hold it against

the floor, and the leg pushed out” when Masello stepped onto the

stool. Because the plaintiff’s motion does not address these and

like opinions in Birnbaum’s report, the court has not addressed

them.

13

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 13 of 16
not be” in other circumstances, “‘depending on the nature of the

issue, the expert’s particular expertise, and the subject of his

testimony.’” Id. at 10 (quoting Kumho, 526 U.S. at 149-50

(further internal quotation marks omitted)).

In Warford, this court identified one such set of

circumstances as where a witness in a products liability case

offers expert testimony based on his own experience with the

product. Id. at 10-11. This court called it “immaterial--and

unsurprising” that the witness would base his opinions on his own

experience, “rather than peer-reviewed studies or other published

literature.” Id. at 11 (citing 3 Frumer & Friedman, supra,

§ 18A.04[6][f], at 18A-80.11). The same observations apply to

Birnbaum’s opinion that the Handy 2-Step was safe for its

intended use, which, as just discussed, is based on his

experience in testing it and similar products.

Third, while Rule 403 authorizes the court to exclude

otherwise admissible testimony to avoid “needless presentation of

cumulative evidence,” the plaintiff has not shown that Birnbaum’s

testimony is in fact needlessly duplicative of that of the

defendants’ other designated liability expert. Indeed, the

plaintiff has not provided the court with any of the other

expert’s anticipated testimony, which essentially makes any

determination of cumulativeness impossible at this point.

14

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 14 of 16
As the plaintiff emphasizes, courts have used Rule 403 to

exclude cumulative expert opinion testimony, see, e.g., UpsherSmith Labs., Inc. v. Mylan Labs., Inc., 944 F. Supp. 1411, 1440

(D. Minn. 1996) (citing cases), but have not laid down a per se

rule that a party can have only a single expert witness offer the

same conclusion, cf. Green Constr. Co. v. Kan. Power & Light Co.,

1 F.3d 1005, 1013 (10th Cir. 1993) (noting that limits on

overlapping expert testimony should not be imposed “on the basis

of mere numbers”). If the trial testimony of Birnbaum and the

defendants’ other designated liability expert devolves into the

“needless presentation of cumulative evidence,” the court can

take appropriate action at that time. The plaintiff’s motion to

exclude Birnbaum’s opinion at this point is denied.

C. The defendants’ motion for summary judgment

As noted at the outset, the defendants have also moved for

summary judgment, but have done so on the sole basis that Ezrin’s

opinions are inadmissible, rendering Masello unable to prove his

claims. So, because the court has denied the defendants’ motion

to exclude Ezrin’s opinions, their motion for summary judgment

must also be denied.

15

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 15 of 16
IV. Conclusion

For the foregoing reasons, Masello’s motion to exclude

Birnbaum’s opinion testimony is DENIED, the defendants’ motion 7

to exclude Ezrin’s testimony is DENIED, and the defendants’ 8

motion for summary judgment is DENIED. 9

SO ORDERED.

____________________________

Joseph N. Laplante

United States District Judge

Dated: April 13, 2011

cc: Daniel W. Buckley, Esq.

Gerry D’Ambrosio, Esq.

Peter A. Brown, Esq.

Christopher A. Duggan, Esq.

Gerard A. Butler, Jr., Esq.

Karyn P. Forbes, Esq.

Document no. 7 38.

Document no. 8 40.

Document no. 9 44.

16

Case 1:08-cv-00136-JL Document 71 Filed 04/13/11 Page 16 of 16