Danzy v. CSX Transportation, Inc.

           IN THE UNITED STATES DISTRICT COURT                       
       FOR THE EASTERN DISTRICT OF NORTH CAROLINA                    
                   WESTERN DIVISION                                  
                  No. 5:23-CV-621-BO-BM                              

DARIUS DANZY,                  )                                          
                          )                                          

           Plaintiff,     )                                          
                          )                                          
 v.                       )              ORDER                       
                          )                                          
CSX TRANSPORTATION INC.,       )                                          
                          )                                          
           Defendant.     )                                          

This matter comes before the court on the motion in limine by pro se plaintiff Darius Danzy 
(“plaintiff”) [DE-24] to exclude (“motion to exclude”) the expert testimony of Dr. R.H. Barry 
Sample (“Dr. Sample”).  Defendant CSX Transportation Inc. (“CSX” or “defendant”) filed a 
response in opposition [DE-25], with exhibits [DE-25-1 to 25-5], including Dr. Sample’s written 
expert report [DE-25-1] (“Dr. Sample’s Report”) and curriculum vitae of [DE-25-2].  Plaintiff 
filed a reply [DE-26] with exhibits [DE-26-2 to -26-5], consisting of an executive order and various 
sections of the Code of Federal Regulations.                              
This matter is  also before the court on plaintiff’s motion for leave [DE-27] to file 
supplemental exhibits [DE-27-2 to 27-5], consisting of additional reports and drug testing forms, 
in support of his reply [DE-26].  Defendant does not oppose plaintiff’s motion to include the 
supplemental exhibits as part of his reply.  [DE-28].                     
For the reasons provided below, plaintiff’s unopposed motion for leave [DE-27] to file 
supplemental exhibits to his reply [DE-26] is GRANTED, and plaintiff’s motion to exclude expert 
testimony is DENIED.                                                      
                    I.  BACKGROUND                                   
Plaintiff filed this suit against defendant in this action under Title VII of the Civil Rights 
Act of 1964, as amended (“Title VII”) alleging “unlawful employment practices on the basis of 
race.”  Compl. [DE-1-1] at 2.  Plaintiff’s claims arise out of a pre-employment drug-screening that 
defendant administered to plaintiff through third party drug testing companies, Psychemedics 
Corporation (“Psychemedics”) and Omega Laboratories, Inc. (“Omega”).  See generally [DE-1]; 

[DE-1-1]; [DE-9].  Plaintiff alleges that defendant discriminated against him because of his race 
as a “Black-African American” by subjecting him to narcotic testing that disparately impacts the 
“class of Black African Americans” due to the allegedly unreliable and inaccurate method of hair 
follicle testing used by defendant through Psychemedics in its pre-employment drug screening.  
Id.                                                                       
A.   Factual Background                                                   
Defendant is a corporation operating rail-based transportation services in the eastern United 
States and parts of Canada providing interstate delivery of commerce by railway. [DE-9] at ¶ 5; 
Compl. [DE-1-1] at ¶ 5.  Defendant extends offers of employment to candidates for “Safety 
Sensitive Positions” contingent upon the candidate successfully passing a medical examination 

and drug screen performed by a third party.  [DE-9] at ¶ 18.  A urine sample and hair follicle 
sample are to be collected and tested by separate laboratories.  Id. at ¶ 20; Compl. [DE-1-1] at ¶ 
20.  Plaintiff alleges the results are reviewed by a Medical Review Officer (“MRO”), and that 
MRO’s used by the defendant are not licensed to practice medicine in North Carolina.  Compl. 
[DE-1-1] at ¶ 21.                                                         
Defendant extended an offer of employment to plaintiff, contingent upon plaintiff passing 
a medical exam and drug screen.  [DE-9] at ¶ 11.  On or about April 28, 2023, plaintiff “reported 
for an employment physical examination which included a healthcare examination and to provide 


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hair and urine for illicit narcotics screen.”  Compl. [DE-1-1] at ¶ 11.  Plaintiff’s underarm hair 
follicle and urine sample were tested for cocaine metabolites, opi-cod/mor, phencyclidine (PCP), 
amphetamines, marijuana (THC metabolite) and benzodiazepines.  Id. at ¶ 12.   
On May 2, 2023, plaintiff’s underarm hair follicle was tested by Psychemedics.  Id. at ¶13.  

Psychemedics reported to the MRO that plaintiff’s underarm hair follicle tested positive for 
cocaine; plaintiff was notified by the MRO on the same date.   Id. at ¶13; [DE-9] at ¶13.  At this 
time, plaintiff “vehemently denied . . . the accuracy and truthfulness of the results.”  Compl. [DE-
1-1] at ¶ 16.  Plaintiff requested “an immediate resubmission and retest with a new sample at a 
different laboratory” over concerns of possible contamination of the sample.  Id.  at ¶ 17.  Plaintiff 
alleges that defendant ignored or denied this request.  Id.  Defendant represents that it sent 
plaintiff’s hair follicle to a second laboratory, where it tested positive for cocaine metabolites a 
second time.  [DE-9] at ¶ 17.1                                            
On May 8, 2023, despite plaintiff’s objection and request for retesting, defendant sent 
plaintiff an email rescinding plaintiff’s offer of employment “because plaintiff failed to pass the . 

. . drug screen.”  [DE-9] at ¶ 14.  Plaintiff alleges that two days after defendant rescinded plaintiff’s 
offer of employment, his urine had tested negative for drug usage by Clinical Reference Laboratory 
(“CLR”), and defendant failed to consider the urine test results prior to rescinding plaintiff’s offer 
of employment.  Compl. [DE-1-1] at ¶15.                                   
On October 30, 2023, plaintiff filed the instant suit, alleging that the follicle testing he 
experienced “causes significant disparate impact on Black African American employees and job 


1 Defendant does not appear to allege that a new sample was collected and tested at a different laboratory and 
instead appears to have retested the hair follicle tested on April 28, 2023.  Compare Compl. [DE-1-1] at ¶ 17 with 
[DE-9] at ¶ 17 and [DE-9-2] at 2.                                         

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applicants” because “exogeneous environmental exposure to the melanated hair of Black African 
Americans produce[s] false positive results because of how cocaine specifically chemically binds 
to melanin pigmentation of the hair.”  Compl. [DE-1-1] at ¶22.            
B.   Dr. Sample’s qualifications, report, and opinion                     

Pursuant to the scheduling order in this case [DE-16], defendant designated Dr. Sample as 
its retained expert and disclosed Dr. Sample’s Report prepared and signed by Dr. Sample on 
February 21, 2025.  [DE-25] at 2.                                         
Dr. Sample is a forensic toxicologist with a Ph.D. in the field of Pharmacology from 
Indiana University and has worked in the field of forensic toxicology for over thirty-five years.  
[DE-25-1] at ¶ 1.  For over twenty years Dr. Sample worked as the Director of Science and 
Technology for Quest Diagnostics (see [DE-25-2] at 2), “one of the largest forensic workforce 
(workplace) drug testing laboratory providers in the United States.”  [DE-25-1] at ¶ 2.  Dr. Sample 
served two separate four-year terms as a member of the Substance Abuse and Mental Health 
Services Administration (“SAMHSA”) Drug Testing Advisory Board (“DTAB”) and advised on 

the SAMHSA drug testing activities and laboratory certification program.  Id.  at ¶ 3.  Dr. Sample 
continues to serve as a commissioner and laboratory inspector for the College of American 
Pathologists (“CAP”) in its Forensic Drug Testing (“FDT”) accreditation program (“CAP-FDT”).  
Id. at ¶ 2.  Dr. Sample has been licensed or certified by various states as a laboratory director in 
the area of forensic workforce drug testing.  Id.                         
Dr. Sample claims to be knowledgeable about, and familiar with: the “industry standards 
for forensic hair, oral fluid, and urine testing for drugs of abuse” (id. at ¶ 2); the “industry standards 
for the medical review of forensic workforce test results for drugs of abuse” (id. at ¶ 5); and 


                           4                                         
federally regulated drug testing programs including the U.S. Department of Health and Human 
Services  (“DHHS”)  Mandatory  Guidelines  for  federal  workplace  drug  testing  (“Mandatory 
Guidelines”) and the U.S. Department of Transportation’s (“DOT”) drug testing regulations (id. 
at ¶ 4).  Dr. Sample has been qualified “on numerous occasions in courts and other forums as an 

expert in toxicology and the testing of specimens for substances of abuse.”  Id.  at ¶ 1.  
Dr. Sample was retained by defendant to (1) review the testing performed by Psychemedics 
of plaintiff’s underarm hair specimen; (2) review subsequent test results of plaintiff’s underarm 
hair specimen by Omega, an independent laboratory; (3) opine as to the scientific validity of that 
testing; (4) provide expert evidence of the applicable standard of care in forensic workforce drug 
testing; (5) opine as to the reliability of the hair testing, environmental exposure to cocaine, and 
the ethnic background of individuals testing positive for cocaine/metabolites; and (6) respond to 
any other allegations asserted against defendant by plaintiff.  Id.  at ¶ 6.   
Dr. Sample opined that Psychemedics’ test results are accurate and scientifically reliable 
and that Omega’s test results confirmed the accuracy of Psychemedics’ test results.  [DE-25-1] at 

4-9.  Dr. Sample then opined that plaintiff’s negative urine test provided no evidence that 
Psychemedics’ test results were inaccurate or that Psychemedics or reviewing MRO’s breached 
any applicable standard of care.  Id. at ¶ 39.  Dr. Sample responded to several of plaintiff’s 
allegations regarding Psychemedics’ and Omega’s lack of SAMHSA accreditation, possible 
environmental contamination, and the “disparate impact on members of the African American 
community” based on an ethnic bias due to hair melanin content.  Id. at ¶¶ 40-51.  Dr. Sample 
concluded that:                                                           
Based upon my knowledge of forensic workforce drug testing industry standards, 
general  forensic  and  scientific  principles,  and  the  science  and  peer-reviewed 

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scientific literature regarding forensic workforce drug testing, it is my opinion 
within a reasonable degree of scientific certainty that Psychemedics’ handling, 
testing, and reporting of the underarm specimen identified as having been submitted 
for testing by Danzy April 28, 2023, complied with all applicable standards of care 
and its records demonstrate that Psychemedics’ test results are scientifically valid 
and are accurate. There is no factual or scientific basis for any contention that 
Psychemedics’ reported test results are inaccurate or scientifically invalid. 

Id. at ¶ 52.                                                              
                  II.  APPLICABLE LAW                                
Under Rule 26(a)(2) of the Federal Rules of Civil Procedure, “a party must disclose to the 
other parties the identity of any [expert] witness it may use at trial” together “with [a] written 
report—prepared and signed by the witness—if the witness is one retained or specially employed 
to provide expert testimony in the case.”  Fed. R. Civ. Proc. 26(a)(2)(A)-(B).  The report must 
contain, inter alia, “(i) a complete statement of all opinions the witness will express and the basis 
and reasons for them; [and] (ii) the facts or data considered by the witness in forming them.”  Fed. 
R. Civ. Proc. 26(a)(2)(B).                                                
Rule 702 of the Federal Rules of Evidence governs the admissibility of expert testimony.  
Fed. R. Evid. 702.  The proponent of the expert testimony bears the burden of establishing its 
admissibility by a preponderance of evidence.  Cooper v. Smith & Nephew, Inc., 259 F.3d 194, 
199 (4th Cir. 2001).  A district court is granted broad latitude in making its determination on the 
admissibility of proposed expert testimony.  United States v. Gastiaburo, 16 F.3d 582, 589 (4th 
Cir. 1994) (“The trial judge has broad discretion under Rule 702.”).      
Rule 702 provides that expert testimony is appropriate when it “will help the trier of fact 
to understand the evidence or to determine a fact in issue.”  Fed. R. Evid. 702(a).  Rule 702 further 
provides that a witness qualified as an expert may be permitted to testify where “(1) the testimony 

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is based upon sufficient facts or data,” (2) “the testimony is the product of reliable principles and 
methods,” and (3) “the expert has reliably applied the principles and methods to the facts of the 
case.”   Id. (b), (c), and (d).  Courts have distilled Rule 702’s requirements into two crucial 
inquiries:  whether the proposed expert’s testimony is relevant and whether it is reliable.  See 

Kumho Tire Co. v. Carmichael, 526 U.S. 137, 141 (1999); Daubert v. Merrell Dow Pharm., Inc., 
509 U.S. 579, 589 (1993); United States v. Forrest, 429 F.3d 73, 80 (4th Cir. 2005).  The trial court 
must carry out the special gate-keeping obligation of ensuring that expert testimony meets both 
requirements.  Kumho Tire, 526 U.S. at 147.                               
In order to be considered relevant, the proposed expert testimony must appear to be helpful 
to the trier of fact.  See Daubert, 509 U.S. at 591-92.  “Testimony from an expert is presumed to 
be helpful unless it concerns matters within the everyday knowledge and experience of a lay juror.”  
Kopf v. Skyrm, 993 F.2d 374, 377 (4th Cir. 1993) (cited in Lacayo v. Sodoma, 122 F.3d 1061 
(Table), 1997 WL 583639, at *3 (4th Cir. 22 Sept. 1997)); accord Koger v. Norfolk S. Ry. Co., No. 
1:08-0909, 2010 WL 692842, at *1 (S.D. W. Va. 23 Feb. 2010) (citing Kopf).  In addition, the 

information must “assist the trier of fact to understand the evidence or determine a fact in issue.”  
Gell v. Town of Aulander, No. 2:05-CV-00021-FL, 2008 WL 4845823, at *4 (E.D.N.C. 4 Nov. 
2008) (citing Fed. R. Evid. 702).  “Expert testimony which does not relate to any issue in the case 
is not relevant and, ergo, non-helpful.”  Daubert, 509 U.S. at 591 (quoting 3 Weinstein & Berger 
¶ 702[02], p. 702–18; citing United States v. Downing, 753 F.2d 1224, 1242 (3rd Cir. 1985) (“An 
additional consideration under Rule 702—and another aspect of relevancy—is whether expert 
testimony proffered in the case is sufficiently tied to the facts of the case that it will aid the jury in 
resolving a factual dispute.”)).                                          


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“‘[T]he test of reliability is flexible’ and ‘the law grants a district court the same broad 
latitude when it decides how to determine reliability as it enjoys in respect to its ultimate reliability 
determination.’”  United States v. Wilson, 484 F.3d 267, 274 (4th Cir. 2007) (quoting Kumho Tire, 
526 U.S. at 141-42).  One factor pertinent to reliability is the proposed expert’s qualifications.  See 

Sawyer v. Southwest Airlines Co., 243 F. Supp. 2d 1257, 1266 (D. Kan. 2003).  A witness may 
qualify to render expert opinions in any one of the five ways listed in Rule 702:  knowledge, skill, 
experience, training, or education.  Kumho Tire, 526 U.S. at 147.  The Fourth Circuit has ruled 
that, when an expert’s qualifications are challenged, “‘the test for exclusion is a strict one, and the 
purported  expert  must  have  neither  satisfactory  knowledge,  skill,  experience,  training  nor 
education on the issue for which the opinion is proffered.’”  Kopf, 993 F.2d at 377 (quoting Thomas 
J. Kline, Inc. v. Lorillard, Inc., 878 F.2d 791, 799 (4th Cir. 1989)); accord The Harvester, Inc. v. 
Rule Joy Trammell & Rubio, LLC, No. 3:09cv358, 2010 WL 2653373, at *1 (E.D. Va. 2 July 2010) 
(citing Kopf).                                                            
An expert may testify only as to those matters within his identified area of expertise.  

Channel Master Satellite Sys., Inc. v. JFD Elec. Corp., 748 F. Supp. 373, 386 (E.D.N.C. 1990) 
(holding that testimony of an expert which is outside his area of expertise is excludable under Rule 
702).  At the same time, an alleged lack of specific experience on certain details at issue may go 
only to the weight of the expert’s opinions and not dictate that they be excluded.  Thomas J. Kline, 
878 F.2d at 799 (“One knowledgeable about a particular subject need not be precisely informed 
about all details of the issues raised in order to offer an opinion.”) (citing Martin v. Fleissner 
GMBH, 741 F.2d 61, 64 (4th Cir. 1984) (“[L]ack of direct experience is not a sufficient basis to 
reject [a proposed expert’s] testimony, but may affect the weight that testimony is given, a decision 


                           8                                         
properly made by the jury.”)).                                            
On the reliability of an opinion, the Supreme  Court has highlighted non-exhaustive 
“Daubert” factors as helpful in this analysis, including: “a theory’s testability, whether it ‘has been 
a subject of peer review or publication,’ the ‘known or potential rate of error,’ and the ‘degree of 

acceptance . . . within the relevant scientific community.’”  Kumho Tire Co., 526 U.S. at 145, 119 
S.  Ct.  at  1173  (quoting  Carmichael  v.  Samyang  Tires,  Inc.,  923  F.Supp.  1514,  1520 
(S.D.Ala.1996); accord Daubert, 509 U.S. at 589-95; Sommerville v. Union Carbide Corp., No. 
24-1491, 2025 WL 2383496, at *8 (4th Cir. Aug. 18, 2025).  These factors are not exclusive and 
need not be rigidly applied; the court “has considerable latitude in considering other factors that 
bear upon an expert’s reliability in a particular case.”  Collins v. Cottrell Contracting Corp., 733 
F. Supp. 2d 690, 699 (E.D.N.C. 2010).                                     
The admission of expert testimony must be considered within the context of the other rules 
of evidence.  In particular, Rule 403 provides that the court must ensure that the probative value 
of any proffered evidence is not “substantially outweighed by a danger of one or more of the 

following: unfair prejudice, confusing the issues, misleading the jury, undue delay, wasting time, 
or needlessly presenting cumulative evidence.”  Fed. R. Evid. 403.  As this court has noted, 
“[d]espite the court’s ability to exercise broad discretion and flexibility when determining the 
admissibility of expert testimony, the court must balance this discretion with the concerns of Rule 
403 to ensure that the probative value of the proffered testimony is not ‘substantially outweighed 
by the danger of unfair prejudice, confusion of the issues, or misleading the jury.’”  Bouygues 
Telecom, S.A. v. Tekelec, 472 F. Supp. 2d 722, 725 (E.D.N.C. 2007) (quoting earlier version of 
Fed. R. Evid. 403).                                                       


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                     III.  ANALYSIS                                  
As noted above, the gravamen of Dr. Sample’s Report is that “[t]here is no factual or 
scientific basis for any contention that Psychemedics’ reported test results are inaccurate or 
scientifically invalid.”  [DE-25-2] at ¶ 52.  Plaintiff seeks to exclude the testimony of Dr. Sample 

and the hair test results provided by Psychemedics pursuant to Rules 702 and 104(a) of the Federal 
Rules of Evidence.  [DE-24] at 1.  Plaintiff argues that Dr. Sample’s Report does not demonstrate 
sufficient evidence that his opinions are reliable or admissible under Rule 702, alleging that “the 
underlying hair test results are based on insufficient data, unreliable  methodology, and are 
scientifically invalid.”  [DE-24] at 1.                                   
Defendant argues that Dr. Sample’s opinion satisfies both Daubert and Rule 702 because 
Dr. Sample’s opinion (i) is based upon sufficient facts and data; (ii) is the product of reliable 
principles and methods; (iii) reflects a reliable application of the principles and methods to the 
facts of the case.  [DE-25] at 6-7.                                       
A.   Qualified Expert                                                     

To start, the court considers whether Dr. Sample is “qualified as an expert by knowledge, 
skill, experience, training, or education.”  Fed. R. Evid. 702.  Defendant designated and disclosed 
Dr. Sample as its intended expert ([DE-25-3] at 2) in the field of “forensic toxicology – specifically 
the interpretation of drug testing results and the methodology for completing the same” ([DE-25] 
at 5).  As summarized above, defendant points to Dr. Sample’s extensive credentials both in terms 
of his education and training, as well as his knowledge, skill and experience.  [DE-25-1] at 2.  
Plaintiff does not appear to dispute Dr. Sample’s qualifications or expert designation in the 
field of forensic toxicology.  See [DE-24] at 2 (arguing that Dr. Sample “is uniquely positioned to 


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understand the stringent requirements of federal drug testing protocols”).  Instead, plaintiff argues 
that Dr. Sample’s “credentials do not override SAMHSA’s legal mandate.”  [DE-26] at 7.  Based 
on the information before the court, it finds Dr. Sample qualified by knowledge, skill, experience, 
training, or education in the field of forensic toxicology.               

B.   Relevance                                                            
The  Fourth  Circuit  has  found  testimony  to  be  relevant  when  it  meets  “Rule  702’s 
requirement that the expert’s specialized knowledge ‘help the trier of fact . . . understand the 
evidence or to determine a fact in issue.’”  United States v. Young, 916 F.3d 368, 381 (4th Cir. 
2019).  Plaintiff does not appear to argue that Dr. Sample’s report is not relevant to the issue of 
the scientific validity of hair follicle testing.  See generally [DE-24].  Plaintiff primarily brings a 
relevance-based argument that hair follicle testing itself is legally improper as this methodology is 
not included in SAMHSA HHS regulations.  [DE-24] at 1, 3 (“[SAMHSA] in its 2020 Proposed 
Hair Guidelines explicitly excludes [Benzoylecgonine (“BZE”)] as a reliable confirmatory marker 
due to its low concentrations in hair and the absence of validated thresholds.”).  Plaintiff expands 

this argument in his reply, contending that “Congress explicitly assigned SAMHSA the exclusive 
role to regulate drug testing in Federally regulated industries through the Omnibus Transportation 
Employee Testing Act.”  [DE-26] at 2.                                     
As an initial matter, Dr. Sample “served two (2), four-year terms as a Member of the 
[SAMHSA] Drug Testing Advisory Board . .  . , which advises the  Assistant Secretary of 
SAMHSA, on the review of the direction, scope, balance, and emphasis of the SAMHSA drug 
testing activities and the drug testing laboratory certification program.”  [DE-25-1] at 2.  The court 
finds that his experience provides him with unique insights into the scope and requirements of 


                          11                                         
SAMHSA drug testing.  Dr. Sample acknowledges that “only urine drug testing is possible under 
DOT rules” and that the hair sample test that defendant undertook “is not covered by the 
requirements of the DOT, Federal Railroad Administration (‘FRA’), or [SAMHSA].”  Id. at 9.  Dr. 
Sample notes that “[n]either the DOT nor SAMHSA (which the DOT relies on for technical 

guidelines) have published final requirements for hair testing.”  [DE-25-1] at 10.  Specifically, Dr. 
Sample  highlights  that  “SAMHSA  has  only  published  (2020)  Proposed  Hair  Mandatory 
Guidelines ("PHMG") - which discussed the use of hydroxycocaine metabolites as a biomarker 
for cocaine use - and they have not yet published final guidelines for hair testing.”  Id. (emphasis 
added); see also Mandatory Guidelines for Federal Workplace Drug Testing Programs, 85 Fed. 
Reg. 176 (proposed Sept. 10, 2020) (to be codified at 42 C.F.R. cpt. 1).  
The Omnibus Transportation Employee Testing Act of 1991, Pub. L. No. 102-143, Title 
V, 105 Stat. 952 (1991), directed the Secretary of Transportation to develop regulations for the 
testing of employees for drugs and alcohol in four sectors of the transportation industry, including 
railroads.  See  49 U.S.C. § 20140; see also Am. Trucking Ass’ns v. Fed. Highway Admin., 51 F.3d 

405, 407 (4th Cir. 1995).  The statute specifically directs the DOT to “prescribe regulations and 
issue orders, not later than October 28, 1992, related to alcohol and controlled substances use in 
railroad operations.”  49 U.S.C. § 20140(b)(1).                           
Notably while the statute requires that “laboratories and testing procedures for controlled 
substances, incorporate the Department of Health and Human Services scientific and technical 
guidelines,” they do not prohibit a private employer in the railroad industry from conducting 
additional drug testing procedures beyond those prescribed by the DOT.  Indeed, DOT regulations 
expressly contemplate that non-DOT drug tests may be performed in addition to DOT drug tests.  


                          12                                         
See 49 C.F.R. § 40.13 (“How do DOT drug and alcohol tests relate to non-DOT tests?”).  
Moreover, even if plaintiff argues that his hair follicle test failed to satisfy the requirements for a 
non-DOT test under 49 C.F.R. 40.13 (see [DE-26] at 4), the court does not perceive why such a 
failure would render expert testimony about the non-DOT test irrelevant.  In sum, Dr. Sample’s 

Report and opinions are outside the common experience of lay persons and, therefore, explains the 
unique process of hair follicle testing for drug usage.                   
C.   Reliability                                                          
Plaintiff’s primary objections to Dr. Sample’s Report focus on its reliability.  See [DE-24] 
at 2-8.  Specifically, plaintiff contends there is a lack of reliable, scientific evidence surrounding 
the use of BZE as a biomarker in hair testing.  See [DE-24] at 3 (“Dr. Sample’s assertion that the 
detection of 0.54 ng/10 mg of BZE in Mr. Danzy’s underarm hair confirms cocaine ingestion is 
scientifically unsound.”).                                                
Plaintiff lists a litany of attempted citations in support of his citation.2  Plaintiff cites “U.S. 
Department of Justice, 2009” in support of the proposition that “the DOJ found that standard 

decontamination washes, such as those used by Psychemedics, are insufficient to remove these 
residues, particularly in porous or curly hair types common in African Americans.”  Id.3  Plaintiff 
argues that “[SAMHSA] in its 2020 Proposed Hair Guidelines explicitly exclude[] BZE as a 
reliable confirmatory marker due to its low concentrations in hair and the absence of validated 
thresholds . . . [and] acknowledge melanin’s role in drug retention, highlighting the potential for 


2 As noted further below, the court believes that it has been able to discern the intended underlying sources 
for certain of these citations, while for others it has not.              
3 It appears that plaintiff may be referring to a portion of an order by the court in the District of Massachusetts.  
See Jones v. City of Bos., 118 F. Supp. 3d 425, 437, 440 (D. Mass. 2015) (“A 2009 Department of Justice report further 
expressed concern about the use of ratios to distinguish exposure from ingestion, noting that metabolites can be present 
in cocaine as a result of the manufacturing process in unknown ratios.”)  

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ethnic disparities.”  [DE-24] at 3-4.  Plaintiff further claims that “[t]he 0.5 ng/10 mg cutoff used 
by Psychemedics is arbitrary and lacks support from established federal standards.”  Id. at 4.  
Plaintiff cites a “2013 study in Forensic Science International” by “Bourland et al., 2013” that 
allegedly showed that “sweat contamination can lead to false positives in underarm hair, even after 

washing.”  Id.                                                            
Plaintiff additionally points to “Ropero-Miller et al., 2009” in support of his claim that 
“[t]he DOJ has determined that [Psychemedics’ wash protocols, consisting of five aqueous 
washes] are insufficient for curly/African American hair, where contaminants embed deeper into 
the hair cortex.”  Id.  Plaintiff cites “Henderson et al., 1998” in support of his contention that “[a] 
National Institutes of Health (NIH)/National Institute on Drug Abuse (NIDA) study found that 
cocaine concentrations in African American hair are 4-8 times higher than in Caucasian hair after 
equivalent doses.”  Id.  Plaintiff argues that “Psychemedics’ College of American Pathologists 
(CAP) accreditation does not equate to federal compliance, as SAMHSA’s National Laboratory 
Certification Program (NLCP) excludes hair testing.”  Id.  Plaintiff contends that the MROs, 

Anthony Minissale D.O. and Richard Weinstein M.D. “in this case failed to reconcile the negative 
urine test (May 10, 2023) with the positive hair test (May 2nd, 2023) violating [49 C.F.R. § 
40.145].”  Id.                                                            
Plaintiff represents that a 2017 study by “Moeller et al.” in the publication Analytical and 
Bioanalytical Chemistry confirmed the presence of Hydroxycocaine metabolites in cocaine-
contaminated environments, which allegedly shows that such metabolites can form through “non-
enzymatic degradation of cocaine in the presence of heat, light, or humidity, independent of 
biological use.”  Id.                                                     


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Plaintiff summarizes his arguments by claiming that (i) “[t]he marginal cocaine/BZE 
levels, coupled with the negative urine test, strongly suggest environmental exposure rather than 
ingestion”; (ii) “CSX’s reliance on non-SAMHSA-certified testing violates federal precedent”; 
(iii) “The MRO failed to investigate contamination explanations or consider melanin bias, as 

required by 49 CFR § 40.153.”  Id. at 6.  Ostensibly in support of his position, plaintiff cites to 
“Jones v. City of Boston, 2014” and provides a “[l]itigation [h]istory” with multiple citations, as 
discussed below.  Id. at 6-7.                                             
Defendant argues that Dr. Sample’s Report is based on “sufficient facts and data,” and 
specifically, the “128-page Laboratory Documentation Package from Omega Laboratories, Inc.” 
and the “140-page Laboratory Data Package from Psychemedics Corporation.”  [DE-25] at 6.  
Defendant also argues that Dr. Sample’s Report “is the product of reliable principles and methods 
based on his knowledge, skill, experience, training and education, and which are described and 
explained in the Expert Report.”  Id.                                     
The court’s reliability analysis focuses on the “‘principles and methodology’ employed by 

the expert, not on the conclusions reached.”  United States v. Moreland, 437 F.3d 424, 431 (4th 
Cir. 2006) (quoting Daubert, 509 U.S. at 594-95).  “When evaluating expert opinions, ‘courts may 
not  evaluate  the  expert  witness’  conclusion  itself,  but  only  the  opinion’s  underlying 
methodology.’”  Ahmad v. Spinnaker Ins. Co., No. 1:24-CV-176 (PTG/IDD), 2025 WL 1732520, 
at *4 (E.D. Va. June 20, 2025) (quoting Bresler v. Wilmington Tr. Co., 855 F.3d 178, 195 (4th Cir. 
2017).  When engaging in this analysis the court must “consider a variety of factors, including 
whether the method used is generally accepted in the scientific community; the rate of error, if 
known; the existence and maintenance of standards; and whether the expert’s work has been 


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subjected to peer review.”  Id. (citations omitted).                      
Dr. Sample provides a thorough summary of the documents he reviewed in support of his 
report, as well as the work he undertook in forming his opinions.  See [DE-25-1] at ¶¶ 5-6.  Dr. 
Sample notes that both of the laboratories that tested plaintiff’s hair follicle “are accredited under 

the  CAP-FDT  Accreditation  Program  for  hair  testing  as  well  under  the  New  York  State 
Department of Health – Clinical Laboratory Evaluation Program for hair testing” and that they 
both hold “ISO/IEC 17025 accreditation.”  Id. at 10.  Dr. Sample further explains that “North 
Carolina workplace drug testing regulations . . . recognize[] an Approved Laboratory as being one 
accredited by the CAP.”  Id.  This suggests that the methodologies at issue have been accepted at 
least by some of the scientific community and are subject to specific standards, and further that 
Dr. Sample’s endorsement of such methodologies is not unfounded.  With respect to error rates, 
Dr. Sample acknowledges that “environmental contamination, especially for cocaine, is a concern 
in hair drug testing.”  Id.  Yet he references peer-reviewed scientific literature by Psychemedics 
and others, which “demonstrated that an ‘extended’ wash procedure coupled with a wash criterion, 

as used by Psychemedics, would not result in the reporting of a positive drug test in hair externally 
contaminated with cocaine.”  Id. at 11.   In addition to his own experience, Dr. Sample explains 
that his opinion is based on “peer-reviewed scientific literature regarding forensic workforce drug 
testing.”  [DE-25-1] at ¶52.  Dr. Sample also cites peer-reviewed sources in support of his 
conclusions (see ¶¶ 49-50).                                               
Plaintiff’s critique does not make detailed arguments finding fault with specific elements 
of Dr. Sample’s methodology or approach.  Rather, plaintiff’s appears to argue that because other 
sources, including the federal government, have allegedly come to different conclusions, Dr. 


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Sample’s methodologies must be flawed.  Plaintiff’s objections relate to the weight to be given to 
Dr. Sample’s opinions, not their admissibility.  Sommerville v. Union Carbide Corp., No. 24-1491, 
2025  WL  2383496,  at  *9  (4th  Cir.  Aug.  18,  2025)  (“[Q]uestions  regarding  the  factual 
underpinnings of the [expert witness’] opinion affect the weight and credibility of the witness’ 

assessment, not its admissibility.”) (alterations in original) (quoting Bresler v. Wilmington Tr. Co., 
855 F.3d 178, 195 (4th Cir. 2017)); Coryn Group II, LLC v. O.C. Seacrets, Inc., No. WDQ–08–
2764, 2010 WL 1375301, at *7 n.19 (D. Md. 30 March 2010) (“The Court recognizes that the 
flaws [defendant] notes are potentially serious, but even assuming the accuracy of [defendant’s] 
criticisms,  ‘[v]igorous  cross  examination,  presentation  of  contrary  evidence,  and  careful 
instruction on the burden of proof are the traditional and appropriate means of attacking shaky but 
admissible evidence.’”) (quoting Daubert, 509 U.S. at 596)).              
Plaintiff’s numerous superficial citations, including, but not limited to, “Boston Police 
Department Arbitration (2016)”; “EEOC Discrimination Charge (2021)”; “Texas Truck Driver 
Defamation Case (2021)”; and “Massachusetts Court Exclusion of Test Results (2018)” frustrate 

the court’s efforts to identify many of the resources he cites in support of his positions.  See Cnty. 
of Charles Mix v. United States DOI, 799 F. Supp. 2d 1027, 1034 (D.S.D. 2011) (“[I]f Plaintiff 
fails to properly explain a claim and provide adequate citation to support it, this Court will neither 
make Plaintiff’s argument for it nor attempt to guess which portions of the administrative record 
Plaintiff might be relying on.”); cf. also Country Mut. Ins. Co. v. Styck’s Body Shop, Inc., 396 Ill. 
App. 3d 241, 254-55, 335 Ill. Dec. 382, 394, 918 N.E.2d 1195, 1207 (2009) (“A . . . court is entitled 
to have issues clearly defined with pertinent authority cited and cohesive arguments presented . . 
., and it is not a repository into which [a party] may foist the burden of argument and  research.”) 


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(citations omitted).                                                      
While a handful of plaintiff’s cited sources, if credited, support facets of his argument, they 
fall short of showing that Dr. Sample’s report is unreliable.  Nucor Corp. v. Bell, No. 2:06-CV-
02972-DCN, 2008 WL 4442571, at *4 (D.S.C. 11 Jan. 2008) (“Although defendants make valid 

points that speak to the weight the finder-of-fact may give [the proposed expert’s] testimony, their 
criticism does not demonstrate that all of his testimony is so unreliable that it should be excluded”).  
For example, Dr. Sample concedes that the 2009 Ropero-Miller and Stout study, which plaintiff 
cites ([DE-24] at 4) “demonstrated that washing alone may not preclude a positive result from 
environmental contamination, based solely on proposed concentration ratio criteria.”  [DE-25-1] 
at 11.  Yet Dr. Sample counters that “it did not utilize the Psychemedics’ wash criterion nor the 
analysis of hydroxycocaine metabolites, which are now recognized as a reliable biomarker for 
cocaine use” and furthermore that a 2006 study with the same authors applied Psychemedics’s 
testing protocol, which supported Dr. Sample’s position.  Id.             
The  court  makes  no  findings  at  this  stage  of  the  proceedings  on  the  comparative 

persuasiveness of the sources cited by the respective parties, except to find that plaintiff’s citations 
to countervailing authorities fail to demonstrate the Dr. Sample’s report is unreliable.   
Plaintiff cites Jones v. City of Bos., 752 F.3d 38, 41 (1st Cir. 2014), as legal authority in 
support of his position.  In that case, the plaintiffs claimed that a police “department’s program, 
which used hair samples to test for illegal drug use, caused a disparate impact on the basis of race 
in violation of Title VII of the Civil Rights Act of 1964.”  Jones, 752 F.3d at 41.  The First Circuit 
reversed the lower court’s granting of summary judgment for the defendant, finding instead that 
there was a “genuine issue of material fact” on whether the plaintiffs could make “a threshold, 


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prima facie showing of disparate impact.”  Id.                            
On remand, the district court considered several of the arguments, which plaintiff raises 
here, including that “the federal government has chosen not to use hair drug testing in its workplace 
testing programs.”  Jones v. City of Bos., 118 F. Supp. 3d 425, 436 (D. Mass. 2015).  The district 

court also acknowledged evidence supporting that “decontamination procedures . . . [do not] 
completely [remove] cocaine that has bound to melanin in the inner cortex of a hair specimen due 
to  environmental  exposure  and  the  [in]ability  of  the  hair  testing  to  distinguish  between 
environmental cocaine and cocaine that has been processed through a  person’s body.”  Id. at 439-
40.  At the same time, the court found that “plaintiffs have not presented any evidence that shows 
this happens in significant numbers in real-world situations.”  Id. at 440.  Further, the district court 
concluded “that the plaintiffs have failed to present evidence from which a reasonable jury could 
determine that the hair drug test is not predictive of or significantly correlated with drug use”  id. 
at 437 and that “[u]ndisputed evidence . . . suggests that the effect — if any — due to external 
contamination is a small one after the hair samples go through the Psychemedics decontamination 

procedure.”  Id.  While the First Circuit subsequently “vacate[d] the district court’s grant of 
summary judgment to the Department [in part based] on the third prong of the disparate impact 
inquiry,” they did not find that the hair follicle test was inherently flawed.  See Jones v. City of 
Bos., 845 F.3d 28, 36, 38 (1st Cir. 2016) (denying summary judgment on the third prong of the 
disparate impact inquiry, because a reasonable jury could find that the alternative of hair testing 
plus intermittent urinalysis would have generated less of a disparate impact, but also making clear 
that “[n]one of this is to say that the jurors must so find.”).           
Another instructive element of Jones for the instant analysis is the posture in which such 


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questions were considered.  The district court in Jones considered competing evidence, including 
competing  expert  opinions,  when  making  its  findings  on  defendants’  motion  for  summary 
judgment.  See Jones, 118 F. Supp. 3d at 446 (D. Mass. 2015); see also Jones, 845 F.3d at 31 (the 
First Circuit finding on appeal that at the district court, “the parties marshalled their evidence, 

mostly in the form of competing expert opinions concerning the reliability of the test, together 
with affidavits from the Officers denying drug use.”).  The court did not find that the conflicting 
evidence suggested that either side’s experts were unreliable.  See id.; see also Moore v. Intuitive 
Surgical, Inc., 995 F.3d 839, 850 (11th Cir. 2021) (finding “even when ‘a trial court, . . .  rules that 
an experts testimony is reliable, this does not necessarily mean that contradictory expert testimony 
is unreliable.”) (citations omitted).  Accordingly, even if the court considered the Jones case 
persuasive with respect to the issues currently before the court, it does not demonstrate that Dr. 
Sample’s Report is inherently unreliable.                                 
Similarly, to the extent that plaintiff seeks to exclude the hair follicle test results of 
Psychemedics and Omega from this case (see [DE-24] at 1), such a question is premature.  The 

persuasiveness of expert opinions related to topics such as the scientific validity of hair follicle 
tests are more appropriately considered at the dispositive motions or trial stage of a case.   
To the extent that plaintiff’s reference to “Smith v. Psychemedics (2017, Cal. Super. Ct.)” 
([DE-24] at 6) is intended to refer to the unpublished California state court of appeals decision, In 
re J.M., No. D072353, 2018 WL 1442488, at *10 (Cal. Ct. App. Mar. 23, 2018), that case is 
inapposite to the situation here.  In that case the defendant’s expert was rejected based on a finding 
that he was not a disinterested expert due, in part, to the fact that he was “vice president of 
Psychemedics[, i.e., the defendant in that case] laboratory operations.”  In re J.M., No. D072353, 


                          20                                         
2018 WL 1442488, at *10 (Cal. Ct. App. Mar. 23, 2018).  Here, plaintiff makes the conclusory 
argument that “Dr. R.H. Barry Sample’s expert opinion, submitted in support of hair follicle test 
results from an unaccredited competitor, Psychemedic laboratory, presents a fundamental conflict 
of interest.”  [DE-24] at 2.  Yet unlike the situation in /n re .M,, plaintiff readily acknowledges 
that Dr.  Sample is not an employee of Psychemedic, but rather works for a competitor, Quest 
Diagnostic Laboratories.  [DE-24] at 2. 
 In sum, the court makes no findings on which parties’ evidence is more persuasive; that is 
a  question  for  another  day.   Rather,  the  court  finds  that  defendant  has  demonstrated  by  a 
preponderance of the evidence that Dr.  Sample and his report satisfy the standard for expert 
scientific testimony. 
                         IV.  CONCLUSION 
 For the reasons discussed above, plaintiff's unopposed motion for leave [DE-27] to file 
supplemental exhibits to his reply [DE-26] is GRANTED; and plaintiff's motion to exclude [DE- 
24] is DENIED. 
 SO ORDERED, this 19th day of September, 2025. 

                                  United States Magistrate Judge 

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