United States Court of Appeals
For the Eighth Circuit
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No. 19-3637
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Jeffrey McMahon
lllllllllllllllllllllPlaintiff - Appellant
v.
Robert Bosch Tool Corp.; Lowe’s Home Centers
lllllllllllllllllllllDefendants - Appellees
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Appeal from United States District Court
for the Eastern District of Missouri - St. Louis
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Submitted: January 14, 2021
Filed: July 20, 2021
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Before SMITH, Chief Judge, KELLY and ERICKSON, Circuit Judges.
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SMITH, Chief Judge.
Jeffrey McMahon suffered injuries to his right hand while using a RotoZip
Model RZ20 hand-held spiral saw (“saw”). McMahon sued Robert Bosch Tool
Corporation (“Bosch”), the manufacturer, and Lowe’s Home Centers, LLC
(“Lowe’s”), the retailer, using strict liability and negligence products liability theories.
McMahon alleged that he was injured when the saw’s auxiliary handle spontaneously
detached from the saw’s body. The district court1 granted Lowe’s and Bosch’s joint
motion to bar the opinions of McMahon’s expert, Philip Buckley. The court also
granted their joint motion for summary judgment on all claims. McMahon seeks
reversal of both decisions. We affirm.
I. Background
The saw includes a detachable auxiliary handle. As designed, the saw requires
the user to take two actions in order to remove the handle. First, the user must slide a
lock pin to one side. Then, while holding the lock pin, the user must depress a separate
handle-release button. According to McMahon, his injury occurred when the handle
detached from the saw without McMahon having performed either of these two
actions.
McMahon sued Bosch and Lowe’s for design defect (under strict liability and
negligence theories), negligent failure to warn, and negligent supply of a dangerous
instrumentality. He alleged that the saw was defective because (1) the removable
handle involuntarily detached from the base of the saw due to defective components
and design, and (2) it lacked an interlock device that would automatically terminate
rotation on the saw if the handle was removed while the saw was in motion.
McMahon retained Philip Buckley, a mechanical engineer, as an expert witness.
Buckley intended to offer the following opinions:
(1) the handle connections on the saw are defective and caused the release
of the saw that injured McMahon; (2) the handle connection design is
defective and its failure is highly foreseeable because (a) the connection
method on the movable latch invites wear and is susceptible to wear
induced tolerances that reduce handle hold force, (b) wear and tear
1
The Honorable Stephen R. Clark, United States District Judge for the Eastern
District of Missouri.
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reduces the holding force available, and (c) the two-factor locking scheme
is reduced to a one-factor locking scheme in some cases . . . . [And] the
handle release button’s placement on the saw is defective because it
promotes user thumb placement on the button, and the saw should have
had an interlock device to stop the motor once the auxiliary handle
detached.
McMahon v. Robert Bosch Tool Corp., No. 4:18-cv-00583-SRC, 2019 WL 5727340,
at *2 (E.D. Mo. Nov. 5, 2019).
Bosch and Lowe’s moved to exclude Buckley’s opinions under Daubert v.
Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). Additionally, they moved
for summary judgment. The district court granted both motions and dismissed the case.
McMahon appeals.
II. Discussion
McMahon makes two arguments on appeal. First, he argues that the district court
abused its discretion by granting Lowe’s and Bosch’s motion to bar McMahon’s expert
witness. Second, McMahon contends that, regardless of whether the district court
abused its discretion in granting Bosch and Lowe’s Daubert motion, summary
judgment was improper. We disagree.
A. Motion to Exclude Expert Testimony
First, McMahon argues that Buckley should be permitted to opine as to the
saw’s alleged design and warning defects. We review a district court’s decision to bar
expert testimony for abuse of discretion. Gen. Elec. Co. v. Joiner, 522 U.S. 136, 143
(1997); Neb. Plastics, Inc. v. Holland Colors Ams., Inc., 408 F.3d 410, 415 (8th Cir.
2005) (“Decisions concerning the admission of expert testimony lie within the broad
discretion of the trial court, and these decisions will not be disturbed on appeal absent
an abuse of that discretion.” (quoting Anderson v. Raymond Corp., 340 F.3d 520, 523
(8th Cir. 2003))).
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Federal Rule of Evidence 702 governs the admissibility of expert testimony.
First Union Nat’l Bank v. Benham, 423 F.3d 855, 861 (8th Cir. 2005). An expert’s
opinion will be admissible if
[1] the expert’s scientific, technical, or other specialized knowledge will
help the trier of fact to understand the evidence or to determine a fact in
issue; [2] the testimony is based on sufficient facts or data; [3] the
testimony is the product of reliable principles and methods; and [4] the
expert has reliably applied the principles and methods to the facts of the
case.
Fed. R. Evid. 702.
1. Design Defects
The district court did not abuse its discretion when it barred Buckley from
testifying as an expert regarding the saw’s alleged design defects.
In his complaint, McMahon alleged that the saw was defective because (a) the
removable handle involuntarily detached from the base of the saw due to defective
components and design, and (b) it lacked an interlock device that would automatically
terminate rotation on the saw if the handle was removed while it was in motion.
Buckley’s opinion would have asserted that the saw was defective for these two
independent reasons.
a. Handle’s Design
McMahon claimed that the saw’s auxiliary-handle design defect caused it to
detach from the saw—without McMahon sliding the lock pin or depressing the handle-
release button. Here, one point is dispositive: Buckley’s proposed opinion lacked
relevance as it did not fit the facts of this case. Cf. Jaurequi v. Carter Mfg. Co., 173
F.3d 1076, 1083 (8th Cir. 1999) (“Of course, the Daubert reliability factors should
only be relied upon to the extent that they are relevant . . . .”).
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“Federal Rule of Evidence 702 imposes a special obligation upon a trial judge
to ensure that any and all scientific testimony is . . . relevant.” Kumho Tire Co. v.
Carmichael, 526 U.S. 137, 147 (1999) (cleaned up). “An expert opinion that fails to
consider the relevant facts of the case is fundamentally unsupported” and “can offer
no assistance to the jury”; accordingly, it should be excluded. Neb. Plastics, 408 F.3d
at 416; see also Lauzon v. Senco Prods., Inc., 270 F.3d 681, 694 (8th Cir. 2001).
McMahon maintained that the saw’s removable handle involuntarily
detached from the base of the saw when he neither slid the lock pin nor depressed the
release button. In contrast, Buckley’s proposed opinion assumed a materially different
fact—that McMahon did press the handle-release button. In fact, in his deposition,
Buckley acknowledged that he did not even know whether it was possible for the saw’s
handle to detach without depression of the release button “because [he] didn’t try it.”
Pl.’s Mem. Opp’n, Ex. 1, at 82, McMahon v. Robert Bosch Tool Corp., No. 4:18-cv-
00583-SRC (E.D. Mo. 2019), ECF No. 66-1. Thus, his opinion did not rely on the
facts of the case.
The district court did not “manipulate[] the facts of the case in order to find that
Mr. Buckley’s opinions were not relevant,” as McMahon contends. Appellant’s Br. at
19. Rather, McMahon mischaracterizes his own deposition testimony by claiming to
have testified that “he ‘could have’” pressed the release button. Appellant’s Reply Br.
at 13 (quoting Defs.’ Statement of Material Facts, Ex. C, at 25, McMahon v. Robert
Bosch Tool Corp., No. 4:18-cv-00583-SRC (E.D. Mo. 2019), ECF No. 84-3). But
McMahon was resolute during his deposition that he did not depress the button.
Although he “guess[ed] it was physically possible” to press the release button while
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holding the saw, he maintained that he did not. Defs.’ Statement of Material Facts, Ex.
C, at 25.2
McMahon cites Lauzon for support. However, that case is distinguishable. The
plaintiff in Lauzon injured his hand while using a nail gun. 270 F.3d at 684. The nail
gun was designed to rapidly fire nails when the operator depressed the trigger and
contacted the nail gun’s tip with another surface. Id. The plaintiff recollected, though
“uncertain of all the details,” that the nail gun had fired without having contacted
another surface. Id. The plaintiff’s expert tested whether this was possible but found
it was not. Id. at 685. However, the expert also explained that the way the accident
actually must have occurred was consistent with the plaintiff’s perception that the nail
gun had fired in mid-air. Id. Thus, the expert’s testimony was ultimately consistent
2
McMahon testified:
Q. Okay. Did you ever depress the handle release button, before
this accident, on the tool?
A. No.
Q. You would never do that?
A. No.
Q. That would be dangerous?
A. Yeah. I didn’t even know how—well, I guess I could. I guess
it was physically possible.
Q. But you didn’t do that?
A. No.
Id. (emphasis omitted).
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with the plaintiff’s, as well as the sole eyewitness’s who “clearly remember[ed]” the
nail gun contacting the surface. Id. at 695.
Here, Buckley, unlike the expert in Lauzon, failed to show whether it was
possible for the accident to have occurred as McMahon testified that it did. In fact,
Buckley did not even “try” to disconnect the saw’s handle without depressing the
release button, which McMahon testified is how the accident occurred. Pl.’s Mem.
Opp’n, Ex. 1, at 82. And unlike the plaintiff in Lauzon, McMahon did not claim to be
uncertain of the details. Rather, McMahon adamantly maintained that he did not
depress the release button. Further distinguishing this case from Lauzon, Buckley’s
assumption was not corroborated by another witness.
b. Interlock Device
McMahon also alleges that the saw was defective for not having an interlocking-
device safety measure that would stop the saw’s motor if the handle became detached.
This alleged defect is independent of the operation of the release button. Curiously,
McMahon does not address this alternative design in his brief. He thus has not
explained how Buckley’s opinion regarding an alternative design incorporating an
interlock device is reliable. Rather, in his brief, and then in his reply, McMahon
focuses on the alternative design of a screw-on handle. And the concluding sentence,
“Buckley cited numerous other alternative designs,” does not meaningfully advance his
argument. Appellant’s Reply Br. at 8; see Ahlberg v. Chrysler Corp., 481 F.3d 630,
634 (8th Cir. 2007) (“[P]oints not meaningfully argued in an opening brief are
waived.”).
Even if McMahon preserved this argument, the district court did not abuse its
discretion by concluding Buckley’s alternative-design opinion was unreliable when
Buckley (1) did not show “that his proposed modifications [we]re feasible or that they
would not interfere with the saw’s utility”; (2) “failed to adequately develop his
theories” as more than “mere ideas”; (3) did “not prepare[] any alternative designs in
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drawings, computer models, or prototypes”; (4) did not show any existing products
incorporating the feature that he described; and (5) did not present any studies or
scientific literature supporting his theories. McMahon, 2019 WL 5727340, at *8; see
Boerner v. Brown & Williamson Tobacco Corp., 260 F.3d 837, 846 (8th Cir. 2001)
(“We have recognized that when a plaintiff’s sole proof of a defective design is the
designer’s choice not to pursue a safer design, the evidentiary burden is on the plaintiff
to show that the safer alternative design he advocates actually exists.”).3
2. Negligent Failure to Warn
The district court did not abuse its discretion in barring Buckley from providing
an opinion on the sufficiency of the saw’s warnings. McMahon argues that Buckley
should have been permitted to testify regarding the warnings because Buckley
“believes that the warnings are deficient in the way in which the manual is written and
in the way in which it warns.” Appellant’s Br. at 24.
But Buckley testified that McMahon had not retained him to opine on the
warnings4 and that he did not have an opinion as to whether the warnings in the
3
Cf. Dancy v. Hyster Co., 127 F.3d 649, 653–54 (8th Cir. 1997) (upholding a
grant of summary judgment against a plaintiff who alleged that a lift truck was
unreasonably dangerous because it lacked a safety device but failed to provide expert
testimony to support the proposition that a feasible safety device existed); Jaurequi,
173 F.3d at 1084 (affirming exclusion of expert who was prepared to testify that a
device was unreasonably dangerous because it lacked “awareness barriers” but “ha[d]
not attempted to construct or even draw the [barriers], much less test its utility as a
safety device or its compatibility with the [device’s] proper function . . . [n]or . . .
pointed to any manufacturer that incorporate[d the] awareness barriers into . . . similar
farming machinery”).
4
Pl.’s Mem. Opp’n, Ex. 1, at 31 (“I think the warnings in the manual are another
area of concern that I haven’t been asked to look into . . . .”).
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manual were deficient.5 Thus, the district court did not abuse its discretion by barring
Buckley from opining on the saw’s warnings.
B. Motion for Summary Judgment
The district court granted Lowe’s and Bosch’s motion for summary judgment
on McMahon’s claims of strict products liability, negligent design, negligent failure to
warn, and negligent supply of a dangerous instrumentality. The district court concluded
that the claims involved such “complex or technical” information that they required
expert testimony; accordingly, Buckley’s exclusion was fatal to McMahon’s claims.
McMahon, 2019 WL 5727340, at *3. We affirm.
We review the grant of summary judgment de novo. Bachtel v. TASER Int’l,
Inc., 747 F.3d 965, 969 (8th Cir. 2014). We “view[] the evidence in the light most
favorable to [the] nonmovant . . . and giv[e] [him] the benefit of all reasonable
inferences.” Id. at 969–70. The movant must “show[] that there is no genuine dispute
as to any material fact and [that] the movant is entitled to judgment as a matter of law.”
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Buckley testified:
Q. So you don’t have any opinion as to whether or not the manual
Mr. McMahon looked at on the morning of his accident or the night
before the accident was in any way defective because you don’t even
know what it said?
A. I don’t know about that particular thing, right.
Q. Am I right, you have no opinion that the manual that came with
this tool that Mr. McMahon looked at the night before and the morning
of this accident was in any way deficient?
A. I don’t currently have that opinion.
Id. at 87 (bold omitted).
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Id. at 970 (quotation omitted). At the same time, “[a] district court’s determination that
expert testimony is necessary on an issue is reviewed for abuse of discretion.” Id.
McMahon argues that Buckley’s expert testimony was not necessary in this case,
and thus summary judgment was improper, asserting (1) “[t]here is direct evidence of
causation in this case because . . . McMahon personally observed the auxiliary handle
involuntarily detach from the tool” and (2) even if we “ignore[] the only direct
evidence in the case regarding what caused the injury, . . . juries may infer causation
. . . under a res ipsa [loquitur]-type theory.” Appellant’s Br. at 28, 30 (emphasis
omitted).
These arguments are one and the same: McMahon asks us to hold that expert
testimony is not needed because a jury could infer causation from McMahon’s account
under a res ipsa loquitur-type theory. McMahon is correct that “[i]t is well-established
under Missouri law that juries may infer causation and the existence of product defects
based on circumstantial evidence under a res ipsa [loquitur]-type theory such that some
product liability claims may be submitted to juries without expert testimony that
identifies specific product defects.” Hickerson v. Pride Mobility Prods. Corp., 470
F.3d 1252, 1258 (8th Cir. 2006) (emphasis omitted). However, McMahon did not
make this argument before the district court. This argument is noticeably absent from
his response to Lowe’s and Bosch’s motion for summary judgment.6
6
In his response to the motion for summary judgment, McMahon stated that it
“is absolutely incorrect” that he “failed to present evidence that the defectively
designed latch and catch system . . . proximately ca[u]sed Plaintiff’s injuries” because
his “expert specifically concluded . . . ‘The handle connections on this tool are
defective and caused the release of the tool that caused injury to Mr. McMahon.’” Pl.’s
Resp. Opp’n Summ. J. at 2, McMahon v. Robert Bosch Tool Corp., No. 4:18-cv-
00583-SRC (E.D. Mo. 2019), ECF No. 87 (emphasis added) (quoting Pl.’s Mem.
Opp’n, Ex. 2, at 5, McMahon v. Robert Bosch Tool Corp., No. 4:18-cv-00583-SRC
(E.D. Mo. 2019), ECF No. 66-2). McMahon continued to rely on Buckley, rather than
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We generally “do[] not entertain new arguments on appeal from the grant of
summary judgment.” Engelhardt v. Qwest Corp., 918 F.3d 974, 982 (8th Cir. 2019)
(quotation omitted); O.R.S. Distilling Co. v. Brown-Forman Corp., 972 F.2d 924, 926
(8th Cir. 1992) (“A party may not assert new arguments on appeal of a motion for
summary judgment.”). We decline to do so here. See Dunn v. Nexgrill Indus., Inc., 636
F.3d 1049, 1058 (8th Cir. 2011) (explaining that an adverse grant of summary
judgment was proper regarding the appellants’ design defect claim when they failed
to offer any admissible evidence of a defect and that they could not recover under a res
ipsa theory when they did not plead that theory of liability). Thus, the district court did
not abuse its discretion in granting the appellees’ motion for summary judgment.
III. Conclusion
We affirm the district court’s order granting Lowe’s and Bosch’s motions (A) to
bar Buckley as an expert and (B) for summary judgment.
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arguing that Buckley was not necessary to prove his claims. Nowhere did he argue that
summary judgment was improper regardless of whether Buckley was excluded.
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