[J-92A-E-2019] [MO:Donohue, J.]

IN THE SUPREME COURT OF PENNSYLVANIA

WESTERN DISTRICT

RICHARD THOMAS WALSH, EXECUTOR 

OF THE ESTATE OF THOMAS J. WALSH, 

DECEASED

v.

BASF CORPORATION; BAYER 

CORPORATION D/B/A BAYER 

CROPSCIENCE, L.P., AND BAYER 

CROPSCIENCE HOLDING, INC., AND/OR 

BAYER CROPSCIENCE, L.P. AND BAYER 

CROPSCIENCE HOLDING, INC., IN THEIR 

OWN RIGHT; BIOSAFE SYSTEMS, L.L.C.; 

CHEMTURA CORPORATION; CLEARY 

CHEMICAL CORP.; DOW 

AGROSCIENCES, L.L.C.; E.H. GRIFFITH, 

INC.; E.I. DU PONT DE NEMOURS AND 

CO., INC.; G.B. BIOSCIENCES 

CORPORATION; JOHN DEERE 

LANDSCAPING, INC., SUCCESSOR TO 

LESCO, INC.; MONSANTO COMPANY; 

NUFARM AMERICAS, INC.; REGAL 

CHEMICAL CO.; SCOTTS-SIERRA CROP 

PROTECTION CO.; AND SYNGENTA 

CROP PROTECTION, INC.

APPEAL OF: DOW AGROSCIENCES, LLC, 

BAYER CROPSCIENCE, LP, BAYER 

CORPORATION, AND BAYER 

CROPSCIENCE HOLDING, INC.

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No. 14 WAP 2019

Appeal from the Order of the 

Superior Court entered June 20, 

2018 at No. 1661 WDA 2016 

vacating the Order of the Court of 

Common Pleas of Allegheny County 

entered October 14, 2016 at No. GD 

10-018588, and remanding.

ARGUED: October 16, 2019

RICHARD THOMAS WALSH, EXECUTOR 

OF THE ESTATE OF THOMAS J. WALSH, 

DECEASED

v.

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No. 15 WAP 2019

Appeal from the Order of the 

Superior Court entered June 20, 

2018 at No. 1661 WDA 2016, 

vacating the Order of the Court of 

Common Pleas of Allegheny County 
[J-92A-E-2019] [MO: Donohue, J.] - 2

BASF CORPORATION; BAYER 

CORPORATION D/B/A BAYER 

CROPSCIENCE, L.P., AND BAYER 

CROPSCIENCE HOLDING, INC., AND/OR 

BAYER CROPSCIENCE, L.P. AND BAYER 

CROPSCIENCE HOLDING, INC., IN THEIR 

OWN RIGHT; BIOSAFE SYSTEMS, L.L.C.; 

CHEMTURA CORPORATION; CLEARY 

CHEMICAL CORP.; DOW 

AGROSCIENCES, L.L.C.; E.H. GRIFFITH, 

INC.; E.I. DU PONT DE NEMOURS AND 

CO., INC.; G.B. BIOSCIENCES 

CORPORATION; JOHN DEERE 

LANDSCAPING, INC., SUCCESSOR TO 

LESCO, INC.; MONSANTO COMPANY; 

NUFARM AMERICAS, INC.; REGAL 

CHEMICAL CO.; SCOTTS-SIERRA CROP 

PROTECTION CO.; AND SYNGENTA 

CROP PROTECTION, INC.

APPEAL OF: DEERE & COMPANY

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entered October 14, 2016 at No. GD 

10-018588, and remanding.

ARGUED: October 16, 2019

RICHARD THOMAS WALSH, EXECUTOR 

OF THE ESTATE OF THOMAS J. WALSH, 

DECEASED

v.

BASF CORPORATION; BAYER 

CORPORATION D/B/A BAYER 

CROPSCIENCE, L.P., AND BAYER 

CROPSCIENCE HOLDING, INC., AND/OR 

BAYER CROPSCIENCE, L.P. AND BAYER 

CROPSCIENCE HOLDING, INC., IN THEIR

OWN RIGHT; BIOSAFE SYSTEMS, L.L.C.; 

CHEMTURA CORPORATION; CLEARY 

CHEMICAL CORP.; DOW 

AGROSCIENCES, L.L.C.; E.H. GRIFFITH, 

INC.; E.I. DU PONT DE NEMOURS AND 

CO., INC.; G.B. BIOSCIENCES 

CORPORATION; JOHN DEERE 

LANDSCAPING, INC., SUCCESSOR TO 

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No. 16 WAP 2019

Appeal from the Order of the 

Superior Court entered June 20, 

2018 at No. 1661 WDA 2016, 

vacating the Order of the Court of 

Common Pleas of Allegheny County 

entered October 14, 2016 at No. GD 

10-018588, and remanding.

ARGUED: October 16, 2019
[J-92A-E-2019] [MO: Donohue, J.] - 3

LESCO, INC.; MONSANTO COMPANY; 

NUFARM AMERICAS, INC.; REGAL 

CHEMICAL CO.; SCOTTS-SIERRA CROP 

PROTECTION CO.; AND SYNGENTA 

CROP PROTECTION, INC.

APPEAL OF: SYNGENTA CROP 

PROTECTION, INC.

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RICHARD THOMAS WALSH, EXECUTOR 

OF THE ESTATE OF THOMAS J. WALSH, 

DECEASED

v.

BASF CORPORATION; BAYER 

CORPORATION D/B/A BAYER 

CROPSCIENCE, L.P., AND BAYER 

CROPSCIENCE HOLDING, INC., AND/OR 

BAYER CROPSCIENCE, L.P. AND BAYER 

CROPSCIENCE HOLDING, INC., IN THEIR

OWN RIGHT; BIOSAFE SYSTEMS, L.L.C.; 

CHEMTURA CORPORATION; CLEARY 

CHEMICAL CORP.; DOW 

AGROSCIENCES, L.L.C.; E.H. GRIFFITH, 

INC.; E.I. DU PONT DE NEMOURS AND 

CO., INC.; G.B. BIOSCIENCES 

CORPORATION; JOHN DEERE 

LANDSCAPING, INC., SUCCESSOR TO 

LESCO, INC.; MONSANTO COMPANY; 

NUFARM AMERICAS, INC.; REGAL 

CHEMICAL CO.; SCOTTS-SIERRA CROP 

PROTECTION CO.; AND SYNGENTA 

CROP PROTECTION, INC.

APPEAL OF: MONSANTO COMPANY

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No. 17 WAP 2019

Appeal from the Order of the 

Superior Court entered June 20, 

2018 at No. 1661 WDA 2016, 

vacating the Order of the Court of 

Common Pleas of Allegheny County 

entered October 14, 2016 at No. GD 

10-018588, and remanding.

ARGUED: October 16, 2019

RICHARD THOMAS WALSH, EXECUTOR 

OF THE ESTATE OF THOMAS J. WALSH, 

DECEASED

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No. 18 WAP 2019

Appeal from the Order of the 

Superior Court entered June 20, 

2018 at No. 1661 WDA 2016, 
[J-92A-E-2019] [MO: Donohue, J.] - 4

v.

BASF CORPORATION; BAYER 

CORPORATION D/B/A BAYER 

CROPSCIENCE, L.P., AND BAYER 

CROPSCIENCE HOLDING, INC., AND/OR 

BAYER CROPSCIENCE, L.P. AND BAYER 

CROPSCIENCE HOLDING, INC., IN THEIR 

OWN RIGHT; BIOSAFE SYSTEMS, L.L.C.; 

CHEMTURA CORPORATION; CLEARY 

CHEMICAL CORP.; DOW 

AGROSCIENCES, L.L.C.; E.H. GRIFFITH, 

INC.; E.I. DU PONT DE NEMOURS AND 

CO., INC.; G.B. BIOSCIENCES 

CORPORATION; JOHN DEERE 

LANDSCAPING, INC., SUCCESSOR TO 

LESCO, INC.; MONSANTO COMPANY; 

NUFARM AMERICAS, INC.; REGAL 

CHEMICAL CO.; SCOTTS-SIERRA CROP 

PROTECTION CO.; AND SYNGENTA 

CROP PROTECTION, INC.

APPEAL OF: BASF CORPORATION

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vacating the Order of the Court of 

Common Pleas of Allegheny County 

entered October 14, 2016 at No. GD 

10-018588, and remanding.

ARGUED: October 16, 2019

CONCURRING AND DISSENTING OPINION

JUSTICE BAER DECIDED: JULY 21, 2020

I join the majority opinion as to Issues One and Three, subject to the clarifications 

set forth below. I likewise agree with the majority’s mandate, remanding the case to the 

trial court to afford Appellants the opportunity to reassert their challenges to Appellee’s 

expert scientific evidence pursuant to Frye v. United States, 293 F. 1013 (D.C. Cir. 1923). 

I respectfully dissent, however, from Issue Two, as I agree that Appellee’s experts 

engaged in improper extrapolation for the reasons ably set forth by the Chief Justice in 

his dissenting opinion. 
[J-92A-E-2019] [MO: Donohue, J.] - 5

While I join the majority as to Issue One, I write separately to express my view that 

this case involves closer questions as to whether the trial court abused its discretion, 

given the analytical gaps identified by the trial court that call into question the methodology 

employed by Appellee’s experts, as summarized by the Chief Justice, see id. at 6-10. 

Indeed, some of these failings are also detailed in the majority’s recitation of the 

Appellants’ experts’ testimony, see Majority Opinion, slip op. at 24-25. 

Nevertheless, I ultimately agree with the majority that the trial court abused its 

discretion in concluding that Appellee’s experts’ testimonies were inadmissible under Frye

by utilizing its own assessment of the scientific evidence rather than specifically relying 

upon Appellants’ experts’ analysis. While a case may involve such a blatant failure of an 

expert to apply generally accepted methodologies that a trial court need not rely upon the 

opposing party’s expert, trial courts in most cases should be guided by the experts offered 

by the parties rather than determining scientific validity on their own, especially 

considering the diversity of individual judges’ scientific knowledge. See Grady v. FritoLay, Inc., 839 A.2d 1038, 1045 (Pa. 2003) (recognizing the need for “individual judges, 

whose backgrounds in science may vary widely” to be “guided by the consensus that 

exists in the scientific community”). Indeed, the risk of trial courts assuming the role of 

scientific experts in determining what is “generally accepted” is more pronounced as the 

science becomes more complex, as demonstrated by the case at bar. Accordingly, I 

conclude that the trial court sub judice abused its discretion and remand is appropriate.

I additionally write to distance myself respectfully from the majority opinion to the 

extent it declines to recognize the trial court as “gatekeeper” in Frye challenges. Majority 

Opinion, slip op. at 20. As expressed by Judge Beck in Blum v. Merrell Dow 

Pharmaceuticals, Inc., 705 A.2d 1314, 1325 (Pa. Super. 1997), aff’d, 764 A.2d 1 (Pa. 

2000), “the gatekeeping role of the court, far from detracting from the jury’s function, is in 
[J-92A-E-2019] [MO: Donohue, J.] - 6

fact essential to it [as it ensures] that what might appear to the jury to be science is not in 

fact speculation in disguise.”

Finally, I join Part II of the Chief Justice’s dissent, addressing this Court’s prior 

decision in Betz v. Pneumo Abex LLC, 44 A.3d 27 (Pa. 2012).