This opinion is uncorrected and subject to revision before

publication in the New York Reports.

-----------------------------------------------------------------

No. 3 

Sean R., &c.,

 Appellant,

 v.

BMW of North America, LLC, et 

al.,

 Respondents.

Steven J. Phillips, for appellant.

Philip C. Semprevivo, for respondents BMW of North

America, LLC et al.

Leslie McHugh, for respondent Martin Motor Sales, Inc.

Haydn J. Brill, for respondent Hassel Motors, Inc.

American Association for Justice, amicus curiae.

PIGOTT, J.:

Plaintiff Sean R. was born with severe mental and

physical disabilities, which he attributes to in utero exposure

to unleaded gasoline vapor caused by a defective fuel hose in his

mother's BMW. The question on this appeal is whether the courts

below properly precluded two of plaintiff's expert witnesses from

- 1 -
- 2 - No. 3

testifying at trial as to causation. Because the experts did not

rely on generally accepted principles and methodologies in

concluding that plaintiff was exposed to a sufficient

concentration of gasoline vapor to cause his injuries, we affirm.

I.

In May 1989, plaintiff's father, Guy R., purchased a

new BMW 525i for his wife, Debra. She was the only person to

drive the car and used it primarily for running local errands. 

In the spring of 1991, Debra began to notice a smell of

gasoline in the vehicle. She stated the odor "came and went" and

that it would often dissipate as she drove. Debra said she could

tolerate the smell in the summer when she was able to drive with

the windows down, but that at other times it was so strong it

caused her headaches, dizziness and throat irritation. Debra's

family members also noticed the odor when they rode in the

vehicle, and Debra's mother said it made her nauseous and dizzy. 

Eventually, the couple began to smell the odor in their home from

the attached garage where they parked the car at night. 

That March, Debra took the car to Hassel Motors

complaining of the gasoline odor. Hassel could not identify any

problem with the vehicle, however, and made no repairs. Debra

continued driving the vehicle, despite the persistent odor of

gasoline, when she became pregnant with plaintiff in July or

August of 1991. Her husband took the vehicle back to Hassel in

November, at which time Hassel discovered a fuel leakage into the

engine compartment caused by a split fuel hose. In total, Debra

- 2 -
- 3 - No. 3

had driven 6,458 miles in the eight months that she smelled

gasoline in the vehicle. 

Plaintiff was born without difficulty on May 13, 1992. 

Although his initial Apgar scores were 9 and 10 at one and five

minutes after birth, respectively, subsequent testing revealed

that plaintiff suffered from severe mental and physical

disabilities. He was diagnosed with, among other things, spastic

quadriparesis (a form of cerebral palsy), developmental delays,

ventricular asymmetry, delayed myelination, microcephaly, aortic

stenosis, malformed bicuspid valve, tracheomalacia and impaired

visual function. 

Two years later, BMW of North America, LLC issued a

recall of all 525i vehicles made between 1989 and 1991, due to

defects in the feed fuel hoses. It described the defective hoses

as being able to "harden and 'set' over time due to engine

compartment temperatures," making it "possible that seepage

between the hose and the fitting could result because the clamp

cannot provide sufficient sealing force to compensate for the

hardening of the hose." The recall report noted that customers

had associated the defect with a "conspicuous fuel odor."

Plaintiff commenced this personal injury action in

January 2008 against defendants BMW of North America, LLC, BMW of

North America, Inc., BMW (US) Holding Corp. (collectively,

"BMW"), Martin Motor Sales and Hassel. He alleged that the

vehicle's defective fuel hose, and Hassel's failure to timely

discover and fix the defective hose, caused his injuries by

- 3 -
- 4 - No. 3

exposing him in utero to toxic gasoline vapor.

In furtherance of his claims, plaintiff served notice

of his intent to rely on the testimony of ten expert witnesses at

trial, including Linda Frazier, M.D., M.P.H. and Shira Kramer,

M.H.S., Ph.D. As plaintiff's primary causation experts, Dr.

Frazier and Dr. Kramer were prepared to testify that plaintiff's

in utero exposure to gasoline vapor proximately caused his birth

defects. For her part, Dr. Frazier concluded that plaintiff's

mother inhaled 1,000 parts per million (ppm) of gasoline vapor

based on the fact that "she and others experienced symptoms of

acute toxicity during exposure, such as headache, nausea and

irritation of the throat and mucous membranes. In controlled

studies, for symptoms such as these to occur immediately, a

gasoline vapor concentration of at least 1000 ppm . . . is

required." Dr. Frazier then utilized the "Bradford Hill

criteria" to conclude that unleaded gasoline vapor is capable of

causing the types of birth defects plaintiff suffered based on

the link between exposure to the constituent chemicals of

gasoline and adverse birth outcomes. Finally, after ruling out

other possible causes, Dr. Frazier concluded that Debra's "high

peak exposure[]" to gasoline vapor during the first trimester of

her pregnancy was the most likely cause of plaintiff's injuries. 

Dr. Kramer reached similar conclusions with respect to

causation. Using a "weight of the evidence" analysis, she

explained that "gasoline vapor and/or [the] specific chemical

constituents of gasoline vapor" -- specifically toluene and

- 4 -
- 5 - No. 3

benzene -- are "causally related to an elevated risk of birth

defects." Based on the symptoms that plaintiff's mother said she

experienced and Dr. Frazier's estimate that plaintiff was exposed

to 1,000 ppm of gasoline vapor, Dr. Kramer further concluded that

plaintiff's exposure to unleaded gasoline vapor was a substantial

causative factor in plaintiff's birth defects. 

BMW and Hassel moved for summary judgment in November

2010, alleging, as relevant here, that the opinions of

plaintiff's causation experts lacked a proper foundation. 

Supreme Court denied summary judgment, holding that plaintiff's

experts provided a foundation for their opinions. The Appellate

Division modified on grounds not pertinent to this appeal, and

otherwise affirmed (94 AD3d 475, 475 [1st Dept 2012]).

Defendants then moved to preclude plaintiff's causation

experts from testifying at trial or, alternatively, to hold a

hearing in accordance with Frye v United States (293 F 1013 [DC

Cir 1923]). In support of their motions, defendants included the

expert affidavits of Anthony Scialli, M.D. and Peter Lees, Ph.D.,

which challenged the opinions of Dr. Frazier and Dr. Kramer for

reaching novel conclusions and not using generally accepted

principles and methodologies. 

After reviewing lengthy submissions and a number of

supplemental expert reports, Supreme Court granted defendants'

motion to the extent that it precluded the testimony of Drs.

Frazier and Kramer. As relevant here, the court determined that

those experts did not rely on generally accepted methodologies in

- 5 -
- 6 - No. 3

concluding that in utero exposure to unleaded gasoline vapor

caused plaintiff's injuries. After granting plaintiff's motion

for reargument, Supreme Court adhered to its original decision.

The Appellate Division unanimously affirmed and

certified the following question to this Court: "Was the order of

the Supreme Court, as affirmed by this Court, properly made?"

(115 AD3d 432 [1st Dept 2014]).

II.

In toxic tort cases, an expert opinion on causation

must set forth (1) a plaintiff's exposure to a toxin, (2) that

the toxin is capable of causing the particular injuries plaintiff

suffered (general causation) and (3) that the plaintiff was

exposed to sufficient levels of the toxin to cause such injuries

(specific causation) (see Parker v Mobil Oil Corp., 7 NY3d 434,

448 [2006]). Although it is "not always necessary for a

plaintiff to quantify exposure levels precisely" (id.), we have

never "dispensed with a plaintiff's burden to establish

sufficient exposure to a substance to cause the claimed adverse

health effect" (Cornell v 360 W. 51st Realty, LLC, 22 NY3d 762,

784 [2014]). "At a minimum, . . . there must be evidence from

which the factfinder can conclude that the plaintiff was exposed

to levels of th[e] agent that are known to cause the kind of harm

that the plaintiff claims to have suffered" (id., quoting Wright

v Willamette Indus., Inc., 91 F3d 1105, 1107 [8th Cir 1996]). 

Not only is it necessary for a causation expert to

establish that the plaintiff was exposed to sufficient levels of

- 6 -
- 7 - No. 3

a toxin to have caused his injuries, but the expert also must do

so through methods "found to be generally accepted as reliable in

the scientific community" (Parker, 7 NY3d at 449). This "general

acceptance" requirement, also known as the Frye test, governs the

admissibility of expert testimony in New York. It asks "whether

the expert's techniques, when properly performed, generate

results accepted as reliable within the scientific community

generally" (People v Wesley, 83 NY2d 417, 423 [1994]). Although

unanimity is not required, the proponent must show "consensus in

the scientific community as to the [methodology's] reliability"

(id. at 437 [Kaye, J., concurring]). 

Plaintiff and his experts have failed to make that

showing in this case. Dr. Frazier and Dr. Kramer concluded that

plaintiff was exposed to a sufficient amount of gasoline vapor to

have caused his injuries based on the reports by plaintiff's

mother and grandmother that the smell of gasoline occasionally

caused them nausea, dizziness, headaches and throat irritation. 

Plaintiff and his experts have not identified any text, scholarly

article or scientific study, however, that approves of or applies

this type of methodology, let alone a "consensus" as to its

reliability. Therefore, the courts below properly granted

defendants' motion to preclude their testimony at trial.1

1 Due to the procedural posture of this case, our analysis

and holding are limited to the Frye inquiry of whether the

experts' techniques are generally accepted in the scientific

community. We express no opinion on the "separate and distinct"

question of whether there was a proper foundation for their

- 7 -
- 8 - No. 3

Dr. Frazier claims that it is accepted practice in

occupational medicine to use standardized studies of symptoms as

a guide when assessing exposures retrospectively. For support,

she cites to the documentation report for gasoline by the

American Conference of Governmental and Industrial Hygienists

(ACGIH), which synthesizes the results of controlled studies and

states that the threshold for immediate, mild toxic effect is

approximately 1,000 ppm. She also cites to a 1991 study in which

subjects exposed to known quantities of toluene and ethanol

experienced an increase in headaches as their exposure level

increased, as well as a 2008 report on the safety of n-Butyl

alcohol in cosmetic products.

None of those sources, however, establish that Dr.

Frazier's methodology, "when properly performed, generate[s]

results accepted as reliable within the scientific community

generally" (Wesley, 83 NY2d at 423). They merely support her

conclusion that there is a dose-response relationship between

exposure to the chemical constituents of gasoline and symptoms of

toxicity. In Dr. Frazier's own words, the ACGIH report lists the

known "exposure levels which cause people to report symptoms such

as nausea and headache because, on the whole, controlled exposure

studies are reliable." We don't disagree with the scientific

validity of controlled studies or their ability to measure

symptoms in response to a given exposure. But those controlled

opinions (Parker, 7 NY3d at 447).

- 8 -
- 9 - No. 3

studies do not support the inverse approach Dr. Frazier employed

in this case -- working backwards from reported symptoms to

divine an otherwise unknown concentration of gasoline vapor. Dr.

Frazier has not identified on this record any study, report,

article or opinion that admits or employs such a methodology. 

Dr. Frazier's methodology is also fundamentally

different from the true "odor threshold" analysis that has been

admitted in other toxic tort cases. The odor threshold of a

substance is the level at which the substance is capable of

olfactory detection (Manuel v Shell Oil Co., 664 So 2d 470, 477

[5th Cir 1995]). Concentrations below the odor threshold are, by

definition, not detectable by human smell (see Dickens v Oxy

Vinyls, LP, 631 F Supp 2d 859, 863 [WD Ky 2009]). Causation

experts have used odor thresholds to determine, for example, that

a plaintiff was occupationally exposed to 60 ppm of hexane where

hexane cannot be detected below that concentration and the

plaintiff testified that he smelled hexane while working (see

Beckner v Bayer Cropscience, LP, 2011 WL 805788 *6 n 8 [SD W Va,

Mar. 2, 2011, No. 2:05-0530]). Similarly, the expert in

Magistrini v One Hour Martinizing Dry Cleaning (180 F Supp 2d 584

[D NJ 2002], affd 68 Fed Appx 356 [3d Cir 2003]) calculated a

plaintiff's occupational exposure to perchloroethylene (PCE)

based on the chemical's odor threshold, coupled with other

employment information, the cubic footage of the workspace and

industrial literature (id. at 613-614). 

Odor thresholds can be particularly helpful in

- 9 -
- 10 - No. 3

occupational exposure cases, where the odor threshold of a

substance exceeds permissible workplace safety standards (see

Beckner, 2011 WL 805788 at * n 8 [noting that if "one detects the

odor of hexane, there is necessarily an exposure exceeding the

limit set by the National Institute for Occupational Safety and

Health . . . of 50 ppm"]). In some cases, however, the odor

threshold of a substance is far below toxicity. Indeed, as one

of plaintiff's sources explains: 

"Smelling organic solvents is not indicative

of a significant exposure, as the olfactory

nerve can detect levels as low as several

parts per million, which is not necessarily

associated with toxicity. As an example, the

odor threshold of toluene is 0.8 parts per

million, whereas the [threshold limit value]

is 100 parts per million."

(McMartin et al, Pregnancy Outcome Following Maternal Organic

Solvent Exposure: A Meta-Analysis of Epidemiologic Studies, 34

American Journal of Industrial Medicine 288-292, 289 [1998]). 

Defendants state, and plaintiff does not dispute, that

unleaded gasoline in the early 1990s had a very low odor

threshold of between 0.50 and 0.76 ppm. Assuming that is

correct, a person would have been able to detect the odor of

unleaded gasoline vapor at less than 1 ppm. Had Dr. Frazier

applied a true odor threshold methodology in this case, like the

experts in Beckner and Magistrini, the only conclusion she could

have reached was that plaintiff was exposed to at least 1 ppm of

unleaded gasoline -- the minimum level at which gasoline is

detectable by human smell. Instead, Dr. Frazier averred that

- 10 -
- 11 - No. 3

there is a minimum threshold of gasoline vapor beneath which

individuals do not experience headache, nausea or dizziness. And

because Debra experienced headaches, nausea and dizziness, Dr.

Frazier concluded she must have been exposed to at least that

concentration. Plaintiff has not shown that such a "symptomthreshold" methodology, unlike the odor threshold methodology

admitted in other cases, has been generally accepted in the

scientific community.2 

Although it is sometimes difficult, if not impossible,

to quantify a plaintiff's past exposure to a substance, we have

not dispensed with the requirement that a causation expert in a

toxic tort case show, through generally accepted methodologies,

that a plaintiff was exposed to a sufficient amount of a toxin to

have caused his injuries (see Joseph V. Rodricks, Reference Guide

on Exposure Science, in Federal Judicial Center, Reference Manual

on Scientific Evidence at 539 [3d ed 2011] ["The methodological

tools necessary to 'reconstruct' the plaintiff's past exposure

are identical to those used to estimate current exposures, but

2 Plaintiff's reliance on Allen v Martin Surfacing (263 FRD

47 [D Mass 2008]) is similarly misplaced. The expert in that

case "did not rely alone on [the plaintiff's] symptom accounts in

forming his opinion" about plaintiff's exposure to toluene (id.

at 56 [emphasis added]). The expert also considered the known

amount of volatile organic compounds that were used in the

resurfacing process, the manner in which those compounds would

have dissipated in the gymnasium -- including the weather at the

time the solvents were used -- and the pathways of exposure in

concluding that plaintiff's exposure approached the threshold

limit value for toluene (id. at 55-56). Moreover, the defendant

in Allen did not challenge the general acceptance of the expert's

methodology, as defendants do here. 

- 11 -
- 12 - No. 3

the availability of the data necessary to apply those methods may

be limited or, in some cases, nonexistent"]). It was plaintiff's

burden to show that the methodology his experts employed was

generally accepted in the scientific community. Having failed to

meet that burden, the courts below properly precluded Dr.

Frazier's and Dr. Kramer's testimony that plaintiff's exposure to

gasoline vapor caused his injuries. 

Accordingly, the order of the Appellate Division should

be affirmed, with costs, and the certified question answered in

the affirmative.

* * * * * * * * * * * * * * * * *

Order affirmed, with costs, and certified question answered in

the affirmative. Opinion by Judge Pigott. Judges Rivera, AbdusSalaam, Stein and Fahey concur. Chief Judge DiFiore and Judge

Garcia took no part.

Decided February 11, 2016

- 12 -