HARTLE et al v. FIRSTENERGY GENERATION CORPORATION
Filing
178
MEMORANDUM OPINION re 112 PLAINTIFF’S DAUBERT MOTION TO LIMIT THE TESTIMONY OF DEFENDANT’S EXPERT PETER J. DRIVAS filed by MICHAEL HARTLE, JESSICA HARTLE. Signed by Chief Judge Joy Flowers Conti on 3/17/2014. (blr)
IN THE UNITED STATES DISTRICT COURT
FOR THE WESTERN DISTRICT OF PENNSYLVANIA
Hartle et al.,
Plaintiffs,
v.
Civil Action No. 08-1019
FirstEnergy Generation Corp.,
Defendant.
Patrick et al.,
Plaintiffs,
v.
Civil Action No. 08-1025
FirstEnergy Generation Corp.,
Defendant.
Price et al.,
Plaintiffs,
v.
Civil Action No. 08-1030
FirstEnergy Generation Corp.,
Defendant.
MEMORANDUM OPINION
CONTI, Chief District Judge
I.
Introduction
Before the court are expert challenges in three cases consolidated for discovery,
Hartle v. FirstEnergy Generation Corp. (No. 08-1019), Patrick v. FirstEnergy
Generation Corp. (No. 08-1025), and Price v. FirstEnergy Generation Corp. (No. 081030). These cases involve the Bruce Mansfield Power Plant (“Bruce Mansfield”), a
coal-fired electric generating facility located along the Ohio River in Shippingport,
Pennsylvania. Bruce Mansfield is owned and operated by defendant FirstEnergy
Generation Corporation (“FirstEnergy” or “defendant”). The plaintiffs allege harm
from air pollution discharged by Bruce Mansfield. The alleged pollution came in the
form of “white rain,” a chronically discharged corrosive material, and “black rain,” a
1
dark-colored sooty residue discharged on two occasions in 2006 and 2007. The white
rain and black rain were deposited on the area surrounding Bruce Mansfield,
allegedly causing property damage and adverse health effects. The plaintiffs in Hartle
are two parents seeking damages for adverse health effects sustained by their minor
daughter. The named plaintiffs in Patrick are four couples who make class-action
claims for damages due to diminution of property value and seek to enjoin the plant
from operating until it can prevent the white rain emissions. In Price, nineteen
plaintiffs seek monetary damages for adverse health effects and property damage and
seek injunctive relief.
The parties conducted extensive fact and expert discovery in these cases.
Defendant filed motions to limit or preclude the testimony of twelve of plaintiffs’
experts. Plaintiffs filed motions to limit or preclude the testimony of seven of
defendant’s experts. This memorandum opinion addresses the parties’ air modeling
experts—Ronald Petersen, PhD (“Petersen”), Peter J. Drivas, PhD (“Drivas”), and
Nicholas Cheremisinoff, PhD (“Cheremisinoff ”).1 The motions to exclude these
experts are fully briefed, and the court heard testimony and argument on January 13,
2014.
II.
Legal Standards
Federal Rule of Evidence 702 governs the admissibility of expert testimony and
states:
A witness who is qualified as an expert by knowledge, skill,
experience, training, or education may testify in the form of
an opinion or otherwise if:
1
The motions to preclude the opinions of Petersen are ECF No. 173 (Patrick) and
ECF No. 130 (Price). The motions to limit the opinions of Drivas are ECF No. 112
(Hartle), ECF No. 212 (Patrick), and ECF No. 91 (Price). The motions to preclude
the opinions of Cheremisinoff are ECF No. 163 (Patrick) and ECF No. 109 (Price).
Unless otherwise noted, ECF numbers appearing in the text of this opinion refer to
the Patrick case, No. 08-1025.
2
(a) 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;
(b) the testimony is based on sufficient facts or data;
(c) the testimony is the product of reliable principles and
methods; and
(d) the expert has reliably applied the principles and
methods to the facts of the case.
FED. R. EVID. 702. Under the seminal case of Daubert v. Merrell Dow
Pharmaceuticals, Inc., 509 U.S. 579 (1993), district courts must act as gatekeepers to
2
“ensure that any and all scientific testimony or evidence admitted is … reliable.” Id. at
589. The United States Court of Appeals for the Third Circuit explained that Rule 702
“embodies a trilogy of restrictions” that expert testimony must meet for admissibility:
qualification, reliability and fit. Schneider ex rel. Estate of Schneider v. Fried, 320 F.3d
396, 404 (3d Cir. 2003). The party offering the expert testimony has the burden of
establishing each of these requirements by a preponderance of the evidence. In re
TMI Litig., 193 F.3d 613, 663 (3d Cir. 1999).
A. Qualification
An expert witness’s qualification stems from his or her “knowledge, skill,
experience, training, or education.” FED. R. EVID. 702. The witness therefore must
have “specialized expertise.” Schneider, 320 F.3d at 405. The court of appeals
interprets the qualification requirement “‘liberally,’ holding that ‘a broad range of
knowledge, skills, and training qualify an expert as such.’” Calhoun v. Yamaha Motor
Corp., U.S.A., 350 F.3d 316, 321 (3d Cir. 2003) (quoting In re Paoli R.R. Yard PCB
Litig., 35 F.3d 717, 741 (3d Cir. 1994)). When evaluating an expert’s qualifications,
district courts should not insist on a certain kind of degree or background. Robinson
2
While Daubert applied exclusively to scientific testimony, see Daubert, 509 U.S. at
590 n.8, the Supreme Court subsequently extended the district court’s gatekeeper
function to all expert testimony. Kuhmo Tire Co. v. Carmichael, 526 U.S. 137, 147
(1999).
3
v. Hartzell Propeller Inc., 326 F. Supp. 2d 631, 667 (E.D. Pa. 2004). An expert’s
qualifications are determined with respect to each matter addressed in the proposed
testimony. Calhoun, 350 F.3d at 322 (“An expert may be generally qualified but may
lack qualifications to testify outside his area of expertise.”). “While the background,
education, and training may provide an expert with general knowledge to testify
about general matters, more specific knowledge is required to support more specific
opinions.” Id.
B. Reliability
In Daubert, the Supreme Court stated that the district court’s gatekeeper role
requires “a preliminary assessment of whether the reasoning or methodology
underlying the testimony is … valid and of whether the reasoning or methodology
properly can be applied to the facts in issue.” Daubert, 509 U.S. at 592–93. While the
Court noted in Daubert that district courts were permitted to undertake a flexible
inquiry into the admissibility of expert testimony under Rule 702, the court of
appeals has enumerated the following eight factors that a district court may examine:
1. whether a method consists of a testable hypothesis;
2. whether the method has been subjected to peer review;
3. the known or potential rate of error;
4. the existence and maintenance of standards controlling the technique’s
operation;
5. whether the method is generally accepted;
6. the relationship of the technique to methods which have been
established to be reliable;
7. the qualifications of the expert witness testifying based on the
methodology; and
8. the non-judicial uses to which the method has been put.
In re Paoli R.R Yard PCB Litigation , 35 F.3d 717, 742 n.8 (3d Cir. 1994) (“Paoli II”).
This list of factors is a “convenient starting point,” but is “neither exhaustive nor
4
applicable in every case.” Kannankeril v. Terminix Int’l, Inc., 128 F.3d 802, 806–07 (3d
Cir. 1997).
Under these factors, experts are not permitted to engage in a “haphazard,
intuitive inquiry,” but must explain the research and methodology they employed in
sufficient detail in order to allow the other party’s expert to test that hypothesis. Oddi
v. Ford Motor Co., 234 F.3d 136, 156 (3d Cir. 2000). Where an expert fails to use
standards to control his or her analysis, “no ‘gatekeeper’ can assess the relationship of
[the expert’s] method to other methods known to be reliable and the non-judicial
uses to which it has been put.” Id. at 158.
“The evidentiary requirement of reliability is lower than the merits standard of
correctness.” Paoli II, 35 F.3d at 744. “As long as an expert’s scientific testimony rests
upon ‘good grounds, based on what is known,’ it should be tested by the adversary
process—competing expert testimony and active cross-examination—rather than
excluded from jurors’ scrutiny for fear that they will not grasp its complexities or
satisfactorily weigh its inadequacies.” United States v. Mitchell, 365 F.3d 215, 244 (3d
Cir. 2004) (quoting Ruiz-Troche v. Pepsi Cola of P.R. Bottling Co., 161 F.3d 77, 85 (1st
Cir. 1998)).
C. Fit
The Rule 702 requirement that testimony “help the trier of fact to understand
the evidence or to determine a fact in issue” is called the “fit” requirement. Fit
requires that there be a “connection between the scientific research or test result to be
presented and particular disputed factual issues in the case.” Paoli II, 35 F.3d at 743.
“‘Fit is not always obvious, and scientific validity for one purpose is not necessarily
scientific validity for other, unrelated purposes.’” Id. (quoting Daubert, 509 U.S. at
591). The standard for fit is “not that high,” although it is “higher than bare
relevance.” Id. at 745.
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III.
Discussion
Two of the key issues in these cases are the extent of the area affected by the
white rain and the two black rain events and the amount of material deposited by
those events. The parties seek to introduce air modeling experts to opine about these
issues. In calculating the dispersion and deposition of emissions from the white and
black rain events, plaintiffs’ expert Petersen primarily relied on a model called
“AERMOD.” Defendant argues Petersen’s white rain opinions are unreliable because
AERMOD is not an appropriate model for measuring liquid stack discharge and
because Petersen made faulty assumptions in applying the model, among other
reasons. Defendant’s expert Drivas used a model called “AGDISP” for his calculations.
Plaintiffs argue that AGDISP, which was designed for agricultural applications such as
crop dusting, is not scientifically reliable.
As set forth below, the court concludes that, while neither AERMOD nor
AGDISP is perfectly tailored to the white rain issue, the parties’ arguments with
respect to Petersen and Drivas go to weight, not admissibility. Which of the
competing models better reflects the facts of these cases is a matter for the jury to
decide. See In re TMI Litig., 193 F.3d at 682 (“In a Daubert/Paoli II analysis, the focus
is not on determining ‘which of several competing scientific theories has the best
provenance.’” (quoting Ruiz-Troche v. Pepsi Cola of P.R. Bottling Co., 161 F.3d 77, 85
(1st Cir. 1998))). The white rain opinions of Petersen and Drivas are based on valid
reasoning and methodologies.
The court finds that Petersen’s breathing zone and black rain opinions also meet
the requirements for admissibility under Rule 702. The motions to exclude the expert
testimony Petersen and Drivas will be denied. The motions to exclude the expert
testimony of Cheremisinoff will be granted, as he merely vouches for Petersen and his
opinions are needlessly cumulative.
6
A. Defendant’s Motions to Preclude the Expert Opinions of Petersen
1. Petersen’s Expert Reports and Motion to Strike Supplemental Report
Petersen prepared three primary expert reports in August 2012: “Assessment of
White Rain Deposition Around the Bruce Mansfield Plant” (“Petersen White Rain
Rep.”), “Assessment of Black Rain Deposition Around the Bruce Mansfield Plant”
(“Petersen Black Rain Rep.”), and “Summary Report on the Breathing Zone Air
Quality Impacts” (“Petersen Breathing Zone Rep.”). Petersen filed a supplemental
expert report entitled “Response to Drivas Expert Reports” in November 2012
(“Petersen 2012 Rebuttal Rep.”) and filed an additional report in May 2013,
“Response to Dr. Peter J. Drivas Expert Report 6” (“Petersen 2013 Rebuttal Rep.”).
Finally, on January 3, 2014, Petersen submitted a “Refined Assessment of White Rain
Deposition Around the Bruce Mansfield Plant.” Defendant moved to strike the last
report as untimely and prejudicial (ECF No. 262). As a preliminary matter, the court
will deny the motion to strike.
Petersen’s 2014 report was submitted over a year after the court’s deadline for
supplemental expert reports, October 15, 2012. (ECF No. 101.) The court has broad
discretion to enforce its discovery case management orders and may exclude
untimely expert reports under Rule 37 of the Federal Rules of Civil Procedure. See In
re TMI Litig., 193 F.3d at 722 (affirming district court’s exclusion of expert reports
persistently filed late in “flagrant violation of pre-trial orders”). The court of appeals
enumerated several factors for courts to consider when evaluating whether to exclude
evidence under Rule 37:
“(1) the prejudice or surprise in fact of the party against
whom the excluded witnesses would have testified, (2) the
ability of that party to cure the prejudice, (3) the extent to
which waiver of the rule against calling unlisted witnesses
would disrupt the orderly and efficient trial of the case or of
other cases in the court, and (4) bad faith or willfulness in
failing to comply with the district court's order.”
7
Id. at 721 (quoting Meyers v. Pennypack Woods Home Ownership Ass’n, 559 F.2d 904–
05 (3d Cir. 1977)).
After applying these factors to the instant case, the court concludes that the 2014
supplemental report should not be excluded at this stage. Based upon plaintiffs’
representation that the report contains only “minor change[s] for the purpose of
improved accuracy,” the court finds that the prejudice to the defendant is low. (ECF
No. 266, at 6.) The court does not find bad faith by plaintiffs. Parties have a duty to
supplement their expert reports, both under the Rules of Civil Procedure and the
dictates of sound scientific practice. FED. R. CIV. P. 26(e)(2). Rule 26 does not give
parties the right to freely supplement, especially after court-imposed deadlines.
“‘Courts distinguish “true supplementation” (e.g., correcting inadvertent errors or
omissions) from gamesmanship, and have therefore repeatedly rejected attempts to
avert summary judgment by “supplementing” an expert report with a “new and
improved” expert report.’” CHARLES ALAN WRIGHT, ARTHUR R. MILLER & RICHARD
L. MARCUS, FEDERAL PRACTICE AND PROCEDURE § 2049.1 (quoting Gallagher v. S.
Source Packaging, LLC, 568 F. Supp. 2d 624, 631 (E.D.N.C. 2008)). Plaintiffs, however,
do not appear to be engaged in gamesmanship. The supplement is based upon the
same methods and corrects minor errors. Although Petersen’s second rebuttal report
was also untimely, plaintiffs otherwise adhered to expert discovery deadlines.
Defendant has the opportunity to cure any prejudice. The 2014 supplement was
not before the court at the Daubert hearing on January 13, 2014, and this opinion
does not address the supplement with respect to any Rule 702 issues. Should
defendant feel that the supplement implicates admissibility issues not resolved by the
remainder of this opinion, the court will afford defendant the opportunity until April
7, 2014, to raise those issues in a supplemental Daubert motion. If that motion is
filed, the court will schedule briefing and a hearing on an expedited basis.
Defendant’s motion to strike the supplemental report will be denied. No further
supplementation will be permitted without a compelling justification. See Beller ex rel.
8
Beller v. United States, 221 F.R.D. 696, 701 (D.N.M. 2003) (refusing to “create a system
where preliminary reports could be followed by supplementary reports and there
would be no finality to expert reports, as each side, in order to buttress its case or
position, could ‘supplement’ existing reports and modify opinions previously given”).
2. White Rain Opinions
Petersen modeled the extent of the deposition of white rain on the area
surrounding Bruce Mansfield by using AERMOD. (Petersen White Rain Rep., at iii,
ECF No. 175-2.) AERMOD is the model preferred by the U.S. Environmental
Protection Agency (“EPA”) for regulatory air dispersion modeling. (Id. at 5.) To
predict white rain deposition, Petersen entered inputs for emission rates, droplet size,
stack flow rate and temperature, and meteorological conditions. (Id. at 1.) Petersen
ran the model under three different operating scenarios to reflect changes to the plant
over time. (Id. at 2.) For each of the three scenarios, Petersen produced maps with
contour lines outlining areas where white rain was deposited at a given level. Petersen
mapped deposition for several time periods: total annual deposition, maximum
twenty-four-hour deposition, and maximum one-hour deposition.
Petersen filed a supplemental report in response to criticism from defendant’s
expert Drivas. Drivas criticized AERMOD because it was designed for dry
particulates gasses and does not adequately account for evaporation when applied to
wet droplets as in this case. (Hr’g Tr. 187:15–188:9, Jan. 13, 2014, ECF No. 275.) To
simulate evaporation under different meteorological conditions, Petersen reran
AERMOD assuming no evaporation and assuming fifty percent evaporation.
(Petersen 2012 Rebuttal Rep. 16, ECF No. 242-2.) Petersen corroborated the accuracy
of his updated predictions by using AGDISP and an additional model, “SACTI.” (Id.
at 12–14, 17.) In his 2013 rebuttal report, Petersen refined his predictions by running
the model for meteorological conditions of twenty-five percent or less evaporation.
(Petersen 2013 Rebuttal Rep. 4, ECF No. 175-11.)
9
Defendant challenges the reliability of Petersen’s white rain opinions on five
grounds: (1) Petersen’s models fail to account for evaporation; (2) Petersen’s one-hour
maximum deposition failed to account for actual meteorological conditions; (3) the
SACTI model is unreliable; (4) Petersen did not validate his results by comparing
them to actual field observation; and (5) the models have an error rate of 50 to 200
percent.
AERMOD does not model evaporation, but Petersen altered input parameters to
model dispersion under various evaporation conditions. Petersen used the AGDISP
model to determine the number of hours from 2005 to 2007 during which
evaporation was less than 50 percent. (Hr’g Tr. 103:23–104:9, Jan. 13, 2014, ECF No.
275.) His revised updated model excluded all hours during the three-year period in
which evaporation was more than 50 percent—that is, Petersen assumed that no
material was deposited during those hours. (Id. at 114:25–115:4.)
AERMOD is widely accepted for modeling the dispersion of dry particulate and
gasses. Petersen made some modifications to account for evaporation. In the court’s
view, these adaptations do not change the fundamental soundness of the AERMOD
methodology. See Paoli II, 35 F.3d at 745 n.14 (“[I]f a court finds that an expert has
employed a methodology only slightly different from a methodology that the court
thinks is clearly reliable, the court should be more likely to accept the altered
methodology than if it was evaluating that methodology as an original matter.”).
While defendant may quarrel with the accuracy of Petersen’s handling of evaporation,
this goes to credibility or weight, not admissibility. See id. at 744 (“The judge might
think that there are good grounds for an expert’s conclusion … even if the judge
thinks that a scientist’s methodology has some flaws such that if they had been
corrected, the scientist would have reached a different result.”)
Defendant argues that Petersen’s models did not account for actual
meteorological conditions. The court is unpersuaded by this argument. Petersen
considered meteorological data in his rebuttal reports. After examining
10
meteorological data, Petersen determined the number of hours when there would be
zero evaporation (about 3 percent of the time) and the number of hours when the
evaporation rate would be 50 percent or less (about 11 percent of the time). (Hr’g Tr.
101:2–6, 112:24–113:12, Jan. 13, 2014, ECF No. 275.) Again, flaws in Petersen’s
handling of meteorological data can be addressed through cross-examination and the
testimony of opposing experts.
Defendant argues that the SACTI model used by Petersen is unreliable because
the model does not predict any white rain deposition within one-half mile of Bruce
Mansfield, which is contradicted by the testimony of numerous witnesses. (ECF No.
174, at 8.) Petersen used SACTI to validate AERMOD and show that wet droplets
would travel further than shown by Drivas’s AGDISP model. (Petersen 2013 Rebuttal
Rep. 21, ECF No. 175-11.) Petersen did not intend for SACTI to accurately model
white rain deposition, only to demonstrate that AERMOD is the preferred model.
(ECF No. 242, at 12.) Should Petersen testify about the SACTI model, the court will
instruct the jury that the SACTI model is only to be used to compare AERMOD and
AGDISP and is not evidence of where white rain was actually deposited.
Defendant argues that Petersen failed to validate his modeling results by
comparing them to field observations. (ECF No. 174, at 11.) Petersen, however, did
consider field observations. (See Petersen 2013 Rebuttal Rep. 6–7 figs.1–3 (overlaying
the model’s contours with maps of locations with reported white rain deposition for
the three emission scenarios).) To the extent that the other field observations are
inconsistent with Petersen’s predictions, that evidence goes to weight, not
admissibility. The court does not find a serious methodological flaw with respect to
defendant’s argument the Petersen failed to validate his model because he compared
his results to field observations.
With respect to the error rate of the model, Petersen admitted that the error rate
of AERMOD was a factor of two. (Hr’g Tr. 130:11–15, Jan. 13, 2014, ECF No. 275.) He
testified that this is the generally accepted error rate for air dispersion modeling. (Id.)
11
The AGDISP model preferred by defendant also has an error rate of a factor of two.
(Cheremisinoff Rep. 17–18, ECF No. 165-1.) As AERMOD is widely accepted for
legal and nonlegal air modeling applications, AERMOD’s error rate does not preclude
its use in this case. See Revision to the Guideline on Air Quality Models, 70 Fed. Reg.
68,218, 68,220 (Nov. 9, 2005) (recommending AERMOD as a “state-of-the-science”
air dispersion model after “extensive, independent peer review” and performance
evaluations).
Defendant also attacks Petersen’s white rain opinions on “fit” and helpfulness
grounds. Defendant argues that (1) Petersen failed to consider the frequency of white
rain, (2) the one-hour maximums will distract jurors from the actual visible evidence,
and (3) Petersen’s different models and scenarios are too uncertain to be helpful.
None of these arguments persuades the court that Petersen’s testimony should be
excluded.
Plaintiffs admit that Petersen did not consider the frequency of white rain
deposition, but argue that his testimony is “a piece of the puzzle” that will
“significantly assist the trier of fact.” (ECF No. 242, at 15.) Unlike the opinions of
Wayne Isphording (“Isphording”) and James Millette (“Millette”), which the court
excluded on “fit” and helpfulness grounds, Petersen’s white rain opinions are limited
to the timeframe at issue in these cases. In excluding the expert testimony of
Isphording and Millette, the court noted that whether fly ash particles from Bruce
Mansfield were deposited on plaintiffs’ properties was not a disputed issue—and
should defendant dispute it at trial, plaintiffs could seek to present the testimony of
Isphording and Millette. (ECF No. 278, at 9 n.6, 10 n.7.) While defendant admits that
white rain has occurred intermittently within a half-mile of Bruce Mansfield,
defendant disputes the allegation that white rain has fallen on plaintiffs’ properties.
(Hr. Tr. 168:21–169:14, Jan. 13, 2013, ECF No. 275.) Because there is a connection
between Petersen’s white rain opinions and a disputed issue in the cases, his testimony
satisfies the “fit” requirement.
12
Defendant argues that due to the “inherent rate of error” in air modeling and the
various scenarios presented by Petersen, Petersen’s white rain opinions will not assist
the trier of fact. (ECF No. 174, at 15–16.) Specifically, defendant argues that the
“model showing maximum one-hour hypothetical deposition … is intended to
distract the trier of fact from reliable evidence of ‘white rain’ deposition, without
adding any helpful information.” (Id. at 15.) The court does not view the air models as
distracting or misleading. Defendant will have the opportunity to bring the error rate
and other limitations of the models to the jury’s attention, and the jury will be able to
weigh the expert testimony in the context of the entirety of the evidence presented at
trial.
Defendant relies on LaBauve v. Olin Corp., 231 F.R.D. 632 (S.D. Ala. 2005), for
the proposition that air modeling with a high error rate should be excluded as
unhelpful. This reliance is misplaced. The district court in LaBauve held, in ruling on
a motion for class certification, that air modeling data showing that plaintiffs’
properties received contamination from 1957 to 1971 (thirty-five to fifty years prior
to the relevant time period) was insufficient to establish a present injury in fact or
standing. Id. at 647–48. This situation significantly differs from Petersen’s models.
Petersen used meteorological data from 2005 to 2007 and predicted deposition
during this period, which is relevant to the claims in these cases. Additionally, for the
purposes of the Rule 23 motion, the court in LaBauve accepted the air model as “a
scientifically valid tool for estimating” the dispersion of the airborne contaminants at
issue in that case. Id. at 648.
During oral argument, defendant cited a recent decision from the Southern
District of West Virginia, Coleman v. Union Carbide Corp, Civil No. 11-366, 2013 WL
5461855 (S.D. W. Va. Sept. 30, 2013), in support of the argument that use of
maximum emission estimates affects the reliability of air modeling opinions. (Hr’g Tr.
73:21–74:12, Jan. 14, 2014, ECF No. 276.) The excluded air modeler in Coleman
assumed that “the facility operates continuously at its maximum capacity under
13
worst-case operating conditions,” rather than what the plant was actually emitting.
Coleman, 2013 WL 5461855, at *25 n.11 (internal quotation marks omitted). The
court in Coleman noted:
[The air modeling expert’s] approach of using maximum, not
actual, emissions is apparently rooted in his permit-based
modeling method previously deemed unhelpful. He has
emission sources borrowing data from one another, across
many years, and then combining them with the unexplained
assumption that the target maximum emission rates all
occurred in the same year.
Id. at *25. The Coleman case differs significantly from the cases at bar. Petersen did
not assume a constant maximum emission rate. He determined the maximum singlehour deposition during the three-year period he examined. Petersen testified that
maximum hourly concentration is a typical way of measuring air pollution. (Hr’g Tr.
156:17–157:8, Jan. 13, 2014, ECF No. 275.)
Defendant asserts that Petersen provides “at least seventeen” sets of modeling
results. (ECF No. 174, at 17.) These different models, defendant argues, are likely to
confuse the trier of fact. (Id. at 18.) When asked which of his models is correct,
Petersen explained that each was accurate, just based on a different set of factual
assumptions. (Hr’g Tr. 71:11–21, Jan. 14, 2014, ECF No. 276.) This situation is not one
where the expert lacks sufficient certainty to make a professional judgment. Cf. Schulz
v. Celotex Corp., 942 F.2d 204, 209 (3d Cir. 1991). After the jury determines the actual
facts, it can evaluate which of Petersen’s models, if any, should be accorded
evidentiary weight.
The court concludes that Petersen’s white rain opinions meet the requirements
for admissibility under Rule 702.
3. Black Rain Model
Petersen used AERMOD to model the extent of the deposition of material
emitted in the black rain events on July 22, 2006, and June 10, 2007. Petersen mapped
the contours of what he identified as each event’s “impact zone.” (Petersen Black Rain
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Rep., at iii, ECF No. 175-32.) Defendant argues that Petersen’s black rain opinion
should be precluded to the extent he is offering an opinion that soot deposition
affected every property within the impact zone because “[n]o mathematical model
can predict with total accuracy the deposition on each individual property.” (ECF No.
174, at 24.) Defendant points out that of the twenty-nine plaintiffs residing within
the 2006 event impact zone, three testified that they did not observe soot and of the
seventeen plaintiffs residing within the 2007 event impact zone, three testified that
they did not observe soot. (Id. at 24–25.)
The question whether Petersen’s black rain opinion alone—that is, without
testimony from fact witnesses who observed soot on a property—would constitute
sufficient evidence to prove nuisance or trespass is not currently before the court. The
questions the court must answer are whether the opinion is based upon valid
methods or reasoning and whether it would be helpful to the trier of fact. As the
court indicated on the record at the Daubert hearing, Petersen’s black rain opinion
meets both criteria and is admissible. (Hr’g Tr. 96:2–25, Jan. 14, 2014, ECF No. 276.)
With respect to reliability, the court notes that Petersen’s contours for the 2006
event are consistent with those of defendant’s expert, Drivas. (Id. 6:1–8.) Drivas
disagreed with Petersen’s 2007 event contours, but this disagreement is based on a
factual dispute about the length of the time Bruce Mansfield was emitting black rain,
not any methodological difference. (Id. at 5:10–6:10.) Drivas agreed that Petersen’s
use of AERMOD is appropriate for modeling the black rain events because the black
rain consisted of oily droplets, which do not evaporate. (Id. at 6:11–15.)
The black rain modeling is relevant to a contested issue of fact in these cases.
Whether or not the model can sustain the plaintiffs’ burden of proof in the absence of
other evidence, the model will help the jury by corroborate or contradict other
evidence—that is, it would tend to make facts of consequence more or less probable
than it would be without the evidence. FED. R. EVID. 401. Although Rule 702’s “fit”
standard is higher than “bare relevance,” the standard is “not that high.” See Paoli II,
15
35 F.3d at 745 (“For example, in Paoli I, we held that testimony that PCBs cause liver
cancer ‘fit’ the case even in the absence of plaintiffs who had liver cancer, because an
expert’s affidavit suggested that increased risk of liver cancer was probative of
increased risk of other forms of cancer. See Paoli I, 916 F.2d [829,] 858 [3d Cir.
1990].”). Petersen’s black rain modeling meets that standard.
4. Breathing Zone Model
Petersen used AERMOD to estimate the concentration of particulates due to
emissions from Bruce Mansfield at plaintiffs’ properties. For two emissions scenarios,
Petersen modeled the concentrations of PM10, PM2.5, and arsenic.3 Scenario one
relied upon emissions data from testing done in 1998. Scenario two relied upon data
from stack tests in 2012. Defendant does not challenge the applicability of AERMOD
to modeling these dry particulates. Defendant challenges the reliability of the
scenario one breathing zone model on two grounds: (1) Petersen overstated the total
amount of particulate emitted from Bruce Mansfield; and (2) Petersen applied an
erroneous mass fraction, leading him to overestimate the amount of arsenic and other
metals in the emitted particulate.4 (ECF No. 174, at 19.)
Petersen’s data on the total amount of particulate emitted by Bruce Mansfield
was derived from a test known as “Method 17.” The Method 17 test is not approved
by the EPA for measuring particulate matter from saturated or wet stacks like those at
Bruce Mansfield during the applicable period. 40 C.F.R. pt. 60 app. A-6 (Method 17
§ 1.2) (“This method is not applicable to stacks that contain liquid droplets or are
saturated with water vapor.”). The Method 17 test on the Bruce Mansfield stacks was
performed in 1998 by Radian, a firm hired by defendant. Plaintiffs assert that
3
PM10 is particulate matter less than 10 micrometers in diameter. PM2.5 is fine
particulate matter less than 2.5 micrometers in diameters. (See Hr’g Tr. 197:19–22,
Jan. 13, 2014, ECF No. 275.)
4
The scenario two breathing zone model is not being challenged by defendant.
(Hr’g Tr. 149:19–22, Jan. 13, 2014, ECF No. 275.)
16
defendant turned this stack particulate data over to them in discovery, previously
relied upon the data in regulatory filings, and never objected to the reliability of the
data until the instant Daubert motion. (ECF No. 242, at 17.) Defendant asserts that it
made available to plaintiffs data from tests conducted in 1995, 2007, and 2009 using
the EPA-approved methodology for measuring particulate from wet stacks. (ECF No.
174, at 20 & n.17.)
That Method 17 is not EPA-approved for measuring particulate from stacks
with liquid droplets is evidence that it may not be the best testing protocol, but
Daubert does not require the “best” methodology or data. Paoli II, 35 F.3d at 744
(“The grounds for the expert’s opinion merely have to be good, they do not have to be
perfect.”). The EPA’s use of a different test for regulatory purposes does not
necessarily mean that Method 17 is unreliable when used on saturated stacks.
Petersen testified that he examined the 1995 study, which used the EPA-approved
method, and found that the particulate emission rate “agreed quite well” with what he
found using data from the 1998 Method 17 study. (Hr’g Tr. 161:10–20, Jan. 13, 2014,
ECF No. 275.) The court will not exclude Petersen’s scenario one breathing zone
model on this basis.
Defendant argues that Petersen inappropriately applied mass fractions when
determining the amount of metals in the particulate. (Id. at 22.) Particulate matter is
composed of condensable particulate, which is mostly gaseous while in the stack and
has little metal content, and filterable particulates, which are larger and can be
trapped by filters. (Id. at 21.) Defendant contends that Petersen used a mass fraction
for arsenic—that is, the ratio of the metal to the total particulate—derived only from
filterable particulate. (Id. at 22.) Petersen applied those filterable particulate mass
fractions to the total mass of particulates, which included the condensable
particulates. (Id. at 23.) The condensable particulate was about 90 percent sulfates,
which contain no arsenic. (Id.; Hr’g Tr. 151:7–152:9, Jan. 13, 2014, ECF No. 275.)
17
Defendant argues that this calculation resulted in overestimating the arsenic in the
breathing zone model by about a factor of ten. (ECF No. 174, at 23.)
The disagreement between Petersen and Drivas appears to be how they
interpreted the data from the 1998 Radian test and the 2012 test. (Hr’g Tr. 100:7–21,
Jan. 14, 2014, ECF No. 276.) In Petersen’s view, 90 percent of the total particulate was
sulfuric acid or sulfates, not 90 percent of the condensable particulate. (Id. at 100:10–
14.) Petersen found no differentiation in the reports between how much of the
sulfates was filterable particulate and how much was condensable particulate. (Id. at
100:14–17.) He testified that “there’s no reason not to assume that the mass fraction of
arsenic would be the same in all particulate, total, condensibles plus filterables.” (Hr’g
Tr. 126:15–17, Jan. 13, 2014, ECF No. 275.)
From the briefing, testimony, and argument, the court cannot determine which
expert’s interpretation of the data and application of the mass fraction is correct. The
court’s role, however, is not to determine which expert is correct. The jury should be
permitted to hear the testimony and determine which expert’s opinion is entitled to
more weight. Paoli II, 35 F.3d at 744–45 (“A judge frequently should find an expert’s
methodology helpful even when the judge thinks that the expert’s technique has flaws
sufficient to render the conclusions inaccurate. He or she will often still believe that
hearing the expert’s testimony and assessing its flaws was an important part of
assessing what conclusion was correct and may certainly still believe that a jury
attempting to reach an accurate result should consider the evidence.”).
B. Plaintiffs’ Motions to Limit the Expert Testimony of Drivas
Defendant’s air modeling expert, Drivas, prepared several expert reports
responding to Petersen’s reports. Drivas concluded that AERMOD is inappropriate
for measuring white rain deposition because the model does not properly account for
evaporation. (Drivas Rep. No. 4, at 4, ECF No. 232-1.) Drivas instead applied the
AGDISP model, which was developed to model airborne spraying of pesticide. (Id.)
Using AGDISP, Drivas calculated that over 95 percent of water droplets released from
18
the Bruce Mansfield stacks will evaporate in the air and that almost all droplet
deposition occurs within 1,500 feet of the stack. (Id. at 7, 8.) At a distance of one-half
mile from the stacks, less than 2 percent of released water droplets remain aloft. (Id.
at 10 tbl.4.1.) AGDISP predicted that these remaining droplets evaporate in less than
ten seconds, leading to no deposition beyond one-half mile from the stacks. (Id. at
11.)
Plaintiffs argue that AGDISP is not a reliable methodology for measuring white
rain deposition and seek to preclude Drivas from testifying about the AGDISP model
or his results. Plaintiffs assert that, since the EPA recommends AERMOD for
predicting air dispersion from power plants, AERMOD should be deemed reliable
and AGDISP should be deemed inadmissible. (ECF No. 113, at 10.)5 Plaintiffs argue
that, under the EPA Guideline on Air Quality Models (“EPA guideline”), a model not
on the EPA’s preferred list can only be used in certain circumstances.6 (Id. at 11.)
AGDISP does not satisfy those criteria because it “is not used and has never been
approved for use in modeling wet stack emissions from a stationary smoke stack.” (Id.
at 12.)
The EPA guideline applies to “the application of air quality models for
regulatory purposes.” 40 C.F.R. pt. 51 app. W (preface). Nothing in the EPA guideline
5
Because plaintiffs’ memorandum of law in support of their Daubert motion to
limit the testimony of Drivas was not filed on the Patrick docket, the ECF number
refers to the Hartle case.
6
The EPA guideline permits the use of alternative models in the following
circumstances:
(1) If a demonstration can be made that the model produces concentration estimates equivalent to the estimates obtained using a preferred
model; (2) if a statistical performance evaluation has been conducted
using measured air quality data and the results of that evaluation indicate
the alternative model performs better for the given application than a
comparable model in Appendix A; or (3) if the preferred model is less
appropriate for the specific application, or there is no preferred model.
40 C.F.R. pt. 51 app. W § 3.2.2(b).
19
suggests that any model not on the EPA’s preferred list is scientifically unreliable. The
EPA guideline is “[a]pplicable only to criteria air pollutants” and “is not intended to
be a compendium of modeling techniques.” Id. § 1.0(a). The liquid droplets in white
rain are not a criteria air pollutant, and Petersen admitted that AERMOD does not
model evaporation of wet droplets. (Petersen Dep. 85:12–25, Mar. 27, 2013, ECF No.
175-3.) Since the these cases do not directly involve regulatory action and since
AERMOD is less appropriate for measuring wet droplets than criteria air pollutants,
the EPA guideline does not justify the exclusion of AGDISP as scientifically
unreliable.
AGDISP has a number of limitations that affect its ability to model the white
rain in these cases. The maximum release height that can be entered in the AGDISP
model is 500 feet, but the two stacks at Bruce Mansfield are 600 feet and 950 feet tall.
(Hr’g Tr. 23:8–17, Jan. 14, 2014, ECF No. 276.) AGDISP does not account for plume
rise. (Id. at 2:25–3:4.) Drivas testified that the effect of these limitations is to
underestimate evaporation and overestimate deposition. (Id. 23:18–24:7.) Because the
droplets are actually released above 500 feet, compared to the model they take longer
to settle to the ground, giving them more time to evaporate. (Id.) The AGDISP model
is not validated to predict accurately deposition more than one-half mile of the
source. (Hr’g Tr. 224:22–225:7, Jan. 13, 2014, ECF No. 275.) Drivas determined that
this limitation did not affect the accuracy of the model because any droplets still aloft
a half mile from Bruce Mansfield evaporate quickly and there is no further
deposition. (Id. 227:13–16; Drivas Rep. No. 4, at 10 tbl.4.1, ECF No. 232-1.)
Drivas had “good grounds” for selecting and applying the AGDISP model.
Unlike AERMOD, AGDISP can measure evaporation and accounts for the effect of
humidity, one of the important variables to consider with liquid droplets. (Hr’g Tr.
24:10–15, Jan. 14, 2014, ECF No. 276.) Drivas adequately considered the limitations
inherent in the AGDISP model as applied to the white rain situation and had logical
grounds for concluding that the limitations did not affect the accuracy of the model.
20
These limitations are therefore a matter of the weight to be afforded to Drivas’s
testimony. Drivas’s opinions based upon the AGDISP model meet the reliability
threshold of Daubert and Rule 702.
Neither AGDISP nor AERMOD are perfectly adapted to modeling the white
rain situation at issue in these cases. Each model has strengths and weaknesses.
Deciding which, if either, of these models provides an accurate representation of
white rain deposition is not the province of the court. In re TMI Litig., 193 F.3d at 682
(finding that dispute between two competing scientific theories goes to weight, not
reliability). Plaintiffs’ motions to preclude testimony about AGDISP will be denied.
C. Defendant’s Motions to Preclude the Expert Opinions of Cheremisinoff
Cheremisinoff is a chemical engineer and an expert in fluid dynamics.
Cheremisinoff evaluated the white rain opinions of Petersen and Drivas and provided
“an independent opinion on the methodology applied and overall reliability of the
dispersion calculations performed.” (Cheremisinoff Rep. 7, ECF No. 165-1.)
Specifically, Cheremisinoff considered the effect of evaporation on the ability of
AERMOD to predict accurately white rain deposition. (Id. at 1.) Cheremisinoff
concluded that Petersen’s overall analysis, which included AERMOD simulations with
input data modified to account for evaporation, accurately simulated the white rain
impact zone. (Id. at 4.) Cheremisinoff opined that Drivas unreasonably assumed very
high evaporation rates and very low wind speeds in order to manipulate the analysis
and return misleading results. (Id. at 5.) Defendant challenges the reliability and fit of
these opinions. Because Cheremisinoff ’s opinions are unnecessarily cumulative and
would not help the trier of fact, defendant’s motions to preclude his expert testimony
will be granted.
Cheremisinoff ’s evaluation of Petersen’s white rain opinions amounts to
vouching for Petersen and is cumulative to Petersen’s testimony. Cheremisinoff is not
an air modeler. (Hr’g Tr. 77:1, Jan. 14, 2014, ECF No. 276.) Plaintiffs admit that
Cheremisinoff did not closely examine the modeling files of Petersen or Drivas. (Id. at
21
78:6–8.) Instead, he only read the expert reports of Petersen and Drivas and evaluated
their work “from the macro perspective.” (Id. at 78:8–9.) Cheremisinoff concluded
that AERMOD accurately predicts the deposition of white rain and that Petersen’s
analysis is “reasonable,” “logical,” and “sophisticated.” (Cheremisinoff Rep. 4–5, 7,
ECF No. 165-1.) He reviewed Petersen’s work and found it convincing, but he
performed no independent air modeling analysis.
Plaintiffs argue that Cheremisinoff ’s testimony would be helpful to the jury and
not unduly cumulative because he evaluated Petersen’s work from the standpoint of
chemistry and flow dynamics, expertise that Petersen does not have. (Hr’g Tr. 84:18–
85:23, Jan. 14, 2014, ECF No. 276.) Despite Cheremisinoff ’s different scientific
expertise, the testimony is nevertheless cumulative. In Tunis Brothers Co. v. Ford
Motor Co., 124 F.R.D. 95 (E.D. Pa. 1989), the plaintiff sought to present a second
damages expert. The plaintiff argued that this expert would “not introduce any ‘new’
testimony but will simply present his interpretation of [the original expert’s]
calculations from the perspective of an economist rather than an accountant.” Id. at
97. The court precluded the second expert’s testimony. Id. (“Merely to have partisan
experts appear to vouch for previous experts violates Fed. R. Evid. 403 and would
needlessly present cumulative evidence, waste time, and mislead the jury.”). The same
reasoning applies to the instant case.
Cheremisinoff ’s rebuttal to the opinions of Drivas also would be unhelpful to
the trier of fact. This testimony, specifically the discussion of nucleation and
agglomeration, is not cumulative to Petersen’s rebuttal opinions. Attacking Drivas for
not considering nucleation and agglomeration could mislead the jury, however,
because those mechanisms are very complex and Petersen’s analysis did not consider
their effect either. (Cheremisinoff Dep. 74:19–77:25, May 3, 2013, ECF No. 165-7.)
Cheremisinoff also offered opinions about the credibility of Drivas. (See, e.g.,
Cheremisinoff Rep. 22, ECF No. 165-1 (“These observations demonstrate that Drivas
has manipulated his analysis in order to mislead.”); id at 24 (“The analysis Drivas
22
performed is biased.).) Expert opinion about the credibility of other witnesses
generally is not helpful as it undermines the jury’s credibility-finding function. Coney
v. NPR, Inc., 312 F. App’x 469, 474 (3d Cir. 2009) (“‘[T]he credibility of witnesses is
generally not an appropriate subject for expert testimony.’” (quoting United States v.
Adams, 271 F.3d 1236, 1245 (10th Cir. 2001)); 29 CHARLES ALAN WRIGHT & VICTOR
JAMES GOLD, FEDERAL PRACTICE AND PROCEDURE § 6264 (1997) (“[C]ourts
generally exclude expert opinion as to whether a witness is or is not telling the
truth.”).
Since Cheremisinoff ’s expert testimony would not assist the trier of fact and
would be unduly cumulative or duplicative, the court will grant defendant’s motions.
IV.
Conclusion
For the reasons set forth above, the motions to strike Petersen’s 2014
supplemental expert report will be denied. The motions to exclude the expert
testimony of Petersen and Drivas will be denied. The motions to exclude the expert
testimony of Cheremisinoff will be granted. Appropriate orders will be entered.
Dated: March 17, 2014
By the court:
/s/ Joy Flowers Conti
Joy Flowers Conti
Chief United States District Judge
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