Title: Hamilton v. Kirson

State: maryland

Issuer: Maryland Supreme Court

Document:

Christopher D. Hamilton, et al. v. Benjamin Kirson, et ux., No. 78, September Term, 
2013. 
 
Candace Renee Alston, et al. v. 2700 Virginia Avenue Associates, et al., No. 100, 
September Term, 2013. 
 
 
NEGLIGENCE—LEAD-PAINT POISONING—CIRCUMSTANTIAL EVIDENCE 
Lead-paint poisoned plaintiffs may prove the causation element of a prima facie 
negligence case through purely circumstantial evidence.  When doing so, however, the 
plaintiff must put forth a theory of causation and sufficient supporting evidence that, if 
believed, would permit a jury to draw the necessary logical inferences of the presence of 
lead-based paint on the premises at the relevant time(s).  In the present summary 
judgment cases, the evidence was insufficient to infer that the defendants’ conduct was a 
substantial factor in bringing about the alleged injuries because the plaintiffs failed to put 
forth evidence that the subject properties contained lead-based paint at the relevant 
time(s). 
 
NEGLIGENCE—CIRCUMSTANTIAL EVIDENCE—EXPERT TESTIMONY 
In order for expert testimony to be admissible, a sufficient factual basis must support the 
expert’s opinion so that the opinion does not amount to conjecture, speculation, or 
incompetent evidence.  In these cases, the experts had an insufficient factual basis from 
which to reach the conclusion that the subject properties contained lead-based paint and 
were a substantial contributor to the plaintiffs’ injuries. 
 
 
 
 
 
Argued 3 April 2014 
 
IN THE COURT OF APPEALS OF 
MARYLAND 
  
 
 
 
 
 
 
 
No. 78, September Term, 2013 
 
CHRISTOPHER D. HAMILTON, ET AL. 
 
v. 
 
BENJAMIN KIRSON, ET UX. 
  
 
 
 
 
 
 
 
No. 100, September Term, 2013 
 
CANDACE RENEE ALSTON, ET AL. 
 
v. 
 
2700 VIRGINIA AVENUE 
ASSOCIATES, ET AL. 
  
 
 
 
 
 
 
 
 Barbera, C.J., 
 Harrell, 
   Battaglia, 
 Greene, 
 Adkins, 
 McDonald, 
 Wilner, Alan M. (Retired,  
Specially Assigned), 
 
  
 
JJ. 
  
 
 
 
 
 
 
 
Opinion by Harrell, J. 
  
 
 
 
 
 
 
 
     Filed: June 20, 2014
 
Circuit Court for Baltimore City 
Case No. 24-C-09-003482 
 
 
Circuit Court for Baltimore City 
Case No. 24-C-10-000721 
We consolidate these two cases, Hamilton v. Kirson, No. 78, September Term, 
2013, and Alston v. 2700 Virginia Avenue Associates, No. 100, September Term, 2013, 
for purposes of this opinion.  In each case, a plaintiff or plaintiffs brought, among other 
claims,1 a negligence action against landlords to recover for his or her injuries resulting 
from lead paint poisoning.2  Neither plaintiff adduced direct evidence that the respective 
demised premise was a substantial contributor to the injuries or that the interiors of the 
homes contained lead paint, but rather relied on circumstantial evidence in an effort to 
satisfy the causation element of a prima facie negligence claim.  After discovery was 
conducted, the landlords filed motions for summary judgment, which the Circuit Court 
for Baltimore City granted.  In both cases, the trial judges reasoned that the respective 
plaintiffs failed to produce sufficient evidence to present a prima facie negligence case 
with regard to the causation element.  Our review on appeal focuses on evaluating what 
quantum or quality of circumstantial evidence in lead paint poisoning cases is sufficient 
to satisfy the causation element of a prima facie negligence claim, so as to submit the 
case to the fact-finder.    
 
 
 
 
 
 
 
1 Each case alleged an additional count of unfair trade practices, in violation of the 
Maryland Consumer Protection Act (“CPA”), see Md. Code (1975, 2005 Repl. Vol.), 
Commercial Law Article, § 13-301, et seq., for leasing premises containing lead paint.  
Because the parties did not raise any issue regarding these counts on appeal, we do not 
discuss these claims further and focus solely on the negligence counts.  
 
2 Both cases were initiated by the victims after they reached adulthood. 
 
-2- 
 
Because the facts and issues presented in the consolidated cases differ slightly, we 
set forth first the background of each case.  Then, we shall address collectively the shared 
relevant legal precedents, applying the relevant case law and legal principles to each case. 
I. 
BACKGROUND 
A. Alston v. 2700 Virginia Avenue Assocs.  
On 26 January 2010, Candace Alston filed suit in the Circuit Court for Baltimore 
City against 2700 Virginia Avenue Associates, Theodore Julio, Lawrence Julio, and 
others, alleging that the defendants acted negligently as landlords in providing premises 
containing chipping, peeling, and flaking lead paint in violation of the Baltimore City 
Housing Code (hereinafter, “Housing Code”).3  Subsequently, an Amendment by 
Interlineation added to the causes of action Brian Alston (Candace’s sibling) and his 
claims.  The Complaint and amendments alleged that Candace and Brian (hereinafter, 
collectively the “Alstons”) suffered lead-based paint poisoning, Candace while residing 
 
 
 
 
 
 
 
3 Although not specifically identified in the Complaint, we presume by how the 
case unfolded that the relevant provisions are Housing Code, Baltimore City Code (2000 
Repl. Vol.), Art. 13, § 702, 703 & 706.  Section 702 requires that “[e]very building . . . 
occupied as a dwelling shall, while in use . . . be kept in good repair, in safe condition, 
and fit for human habitation.”  Section 703 provides, in relevant part, that “good repair 
and safe condition shall include . . . [a]ll walls, ceilings, woodwork, doors and windows 
shall be kept clean and free of any flaking, loose, or peeling paint.”  Next, section 706 
requires that (1) “[a]ll interior loose or peeling wall covering or paint shall be removed 
and the exposed surface shall be placed in a smooth and sanitary condition,” and (2) “[n]o 
paint shall be used for interior painting of any dwelling . . . unless the paint is free from 
any lead pigment.” 
 
 
-3- 
 
for consecutive periods at dwellings located at 2752 Virginia Avenue and 2810 Virginia 
Avenue and Brian at 2752 Virginia Avenue. 
For her part, the Alstons’ mother, Leslie Sidbury, could not remember the exact 
time periods and locations of their residences during the relevant times.  The Complaint 
alleged that the Alstons’ mother and her children resided at a number of properties 
between 1989 and 1995.  Specifically, Candace, who was born on 27 January 1989, 
“lived in the dwelling or frequented the dwelling as an invitee of the tenant during 1989-
1995” for the following properties: (1) 3006 Woodland Avenue; (2) 3501 Oakmont 
Avenue; (3) 303 N. Gilmor Street; (4) 2752 Virginia Avenue; and, (5) 2810 Virginia 
Avenue.    
Subsequently, in the Amendment by Interlineation adding as a victim Brian 
Alston, who was born on 13 August 1990, the Alstons narrowed the matter somewhat 
that their mother lived at the 2810 Virginia Avenue property between 1992-1993.  Then, 
they lived as a family at 2752 Virginia Avenue between 1993-1995.  During the 
defendants’ later deposition of Ms. Sidbury, it was discovered that she did not remember 
the exact location of their residence, but approximated that the house was located in the 
2800 block on Virginia Avenue.  Plaintiffs’ blood lead level testing slips listed, however, 
only 3006 Woodland Avenue as their address. 
   During discovery, the Alstons identified Dr. Michael Weitzman as their expert 
witness.  Dr. Weitzman opined, relying on circumstantial evidence solely, that 2752 
Virginia Avenue and 2810 Virginia Avenue (hereinafter, the “subject properties”) were a 
source of, and a substantial contributing factor to, the Alstons’ lead paint poisoning and 
 
-4- 
 
resulting injuries.  To support this opinion, Dr. Weitzman relied on the following facts: 
(1) the Alstons lived in and/or visited the subject properties during the time period that 
they demonstrated elevated blood lead levels; (2) the residences had chipping, peeling, or 
flaking paint during the relevant time period; (3) the residences were older homes in 
Baltimore, built before 1979;4 and (4) the Alstons exhibited elevated blood lead levels at 
the time they lived in the subject properties.  No scientific testing was conducted of the 
paint (chipping, flaking, peeling, or otherwise) at the residences for the presence of lead. 
Defendants (Respondents here) filed a Motion for Summary Judgment on 22 
December 2010, arguing that the Plaintiffs “failed to sustain their burden of proving that 
they were exposed to and ingested chipping, peeling, or flaking lead-based paint in 
violation of the Baltimore City Housing Code at the Defendants’ properties . . . .”  
Specifically, Respondents argued that Plaintiffs’ expert relied on insufficient assumptions 
to provide a factual basis for his opinion that Plaintiffs were exposed to a lead paint 
hazard at Defendants’ properties.  Respondents emphasized that there is no direct 
evidence that Plaintiffs resided at Defendants’ properties or “that Defendants’ properties 
contained lead paint hazards, or defective lead-based paint, during Plaintiffs’ alleged 
tenancy at the properties.”  Moreover, Respondents pointed out that “Plaintiffs’ source 
expert also cannot eliminate [other] potential source[s] of Plaintiffs’ recorded [blood] 
 
 
 
 
 
 
 
4 According to the deposition of Dr. Weitzman, he found the age of the house 
relevant because the State of Maryland issued a report finding that 75% of houses in 
Baltimore City were likely to have lead-based paint if built between 1950 and 1978.  In 
1978, lead-based paint was banned.  This report was not included in the record.  
 
-5- 
 
lead levels, which precludes Plaintiffs from providing adequate circumstantial evidence 
of exposure at the properties.”   
After a hearing on the motion on 6 February 2012, the trial judge granted 
summary judgment, stating: 
In this case, the identification of the address is an interesting issue.  I’m not 
going to grant summary judgment on that basis, because I believe that the 
plaintiff has come up – has come forward with, it may be the barest 
showing, but it’s a bare showing to tie herself to these two addresses on 
Virginia Avenue. 
 
And this is unlike a case where the defendant comes forward with sworn 
statements in whatever form; interrogatories, affidavits, depositions that 
refute any possibility that the plaintiff actually lived or spent time at those 
addresses. 
 
So although it is extremely sketchy in this case, both the identification of 
the specific properties and the years when the plaintiffs were living there, I 
don’t think the defendant prevails on that basis. 
 
I do think the defendant prevails on the basis that as to these 
properties the plaintiffs cannot show the requisite causation of any 
elevated blood lead levels derived from these properties. 
 
I accept that the plaintiffs have shown that there was deteriorating paint at 
the properties.  And I will even, for purposes of the motion go so far as to 
accept that the plaintiffs have shown that they exhibited elevated blood lead 
levels at around the time that they say they were living in these properties. 
What is missing is evidence that would tie those elevated blood lead 
levels to the specific conditions in these properties.  And I accept the 
possibility that that could be proven indirectly by circumstantial 
means. 
 
But I think the essential logical ingredient that must be present in order for 
Dow or a theory like Dow to apply is that logically there must be a -- a 
very strong conclusion that the lead that the plaintiffs were 
experiencing had to come from this source because there is no other 
logical source that is available. 
 
 
-6- 
 
Now, there may be a number of ways that could be done.  I’ve suggested 
one of them would be if there were visitation properties, that there is some 
evidence that tends to exclude those. 
 
There might be evidence that the paint wasn’t deteriorating in those.  There 
might be evidence that they were built after a period when lead paint was 
likely present.  There might be evidence that the visits were very short, 
were supervised closely and the children didn’t ingest paint.  There may be 
a number of bases that might be advanced by plaintiff. 
 
But here you simply have two wide open possible properties at the 
same time, either of which could have been the source of the lead that 
is alleged.  And that is insufficient to establish the prima facie case that 
the plaintiff would have to show on negligence. 
 
. . . 
 
For those reasons, I think that the moving defendants with respect to these 
two addresses on Virginia Avenue are entitled to summary judgment.  And 
I’ll grant summary judgment as to both plaintiffs as to these defendants. 
 
(Emphasis added.)  The trial judge issued a written order to like effect, stating that the 
Motion for Summary Judgment was granted “[f]or the reasons stated on the record at the 
hearing.”   
Plaintiffs appealed timely to the Court of Special Appeals.  The intermediate 
appellate court affirmed the judgment of the trial court in an unreported opinion filed on 
10 July 2013.  Plaintiffs-Petitioners filed a Petition for a Writ of Certiorari, which this 
Court granted, 435 Md. 266, 77 A.3d 1084 (2013), to consider the following questions: 
(1) By following its decision in West v. Rochkind, 212 Md. App. 164, 66 
A.3d 1145 (2013), did [the] CSA [Court of Special Appeals] [here] 
improperly undermine the common law principle that the law makes no 
distinction between the weight to be given to circumstantial evidence and 
direct evidence and that no greater degree of certainty is required of 
circumstantial evidence than of direct evidence?  
 
 
-7- 
 
(2) Did [the] CSA’s decision in West improperly change a Plaintiff’s 
burden of proof in a circumstantial evidence case from “preponderance of 
the evidence” to greater than “beyond a reasonable doubt?”  
 
(3) Does [the] CSA’s holding improperly require a Plaintiff in a lead-paint 
case to prove that a given property was “the only possible explanation” for 
a Plaintiff’s injuries in order to make a circumstantial case? 
 
B. Hamilton v. Kirson 
On 28 May 2009, Christopher Hamilton filed in the Circuit Court for Baltimore 
City his initial complaint alleging several negligence claims against Lola Singer, the 
previous owner of property at 2231 Barclay Street (hereinafter, the “Singer property”), 
and Benjamin and Karen Kirson (hereinafter, collectively the “Kirsons”), the previous 
owners of property at 754 Bartlett Avenue (hereinafter, the “Kirson property” or the 
“subject property”).  According to the Complaint, these properties “contained lead-based 
paint in such deteriorated conditions that it was peeling, chipping and flaking from the 
walls, baseboards, windowsills and other areas of the premises,” as well as the presence 
of lead paint dust and powder.  It was alleged that Christopher, while living at these 
residences, ingested lead-based paint chips and dust and, as a consequence, suffered 
permanent brain damage resulting in developmental and behavioral injuries.  The 
Complaint alleged that Christopher resided at 2231 Barclay Street from 1992-1993, and 
at 754 Bartlett Avenue from 1993-1995.   
On 21 August 2009, the Complaint was amended to add a second plaintiff—
Christopher’s brother, Rickey—as well as additional defendants and allegations.  
Specifically, the Hamiltons added allegations that they were exposed to lead-based paint 
at 445 E. Lanvale Street, where they lived from 1991-1992 and which was owned and 
 
-8- 
 
managed by Ralph Small and the Patella Realty Corporation, the added defendants.  On 2 
April 2010, the Hamiltons amended their complaint again to add allegations involving 
two additional properties which Plaintiffs visited as children and which were owned and 
managed by other newly-added defendants.5   
Rickey was born on 5 April 1989.  From his birth until approximately April of 
1990, Rickey lived with his mother, maternal grandparents, sister, and uncle somewhere 
on the 2300 block of Barclay Street.  Rickey moved with the same family members to 
445 East Lanvale Street approximately in the summer of 1990.  A short time later, on 5 
September 1990, Christopher was born and lived in the same house as Rickey from that 
point in time.  At some point in 1992, the family moved to 2231 Barclay Street where 
they resided until approximately the fall of 1993, at which time the family moved again 
to 754 Bartlett Avenue.  The family lived at that address until some point in 1995.  Then, 
the family moved to 1604 Gorsuch Avenue, where they resided until 1998.  Between 
1990 and 1994, Rickey was tested six times for blood lead levels (“BLL”).  Between 
1991 and 1995, Christopher was tested nine times.  The results of these tests are detailed 
in the following chart: 
 
 
 
 
 
 
 
 
5 Ultimately, due to a recognized lack of evidence regarding several of the 
additional properties, the Hamiltons dismissed, prior to the summary judgment stage, 
their claims against all defendants, save Singer and the Kirsons.  Singer was not 
dismissed as a defendant until after the Hamiltons noted an appeal to the Court of Special 
Appeals.  Thus, our discussion of the relevant facts focuses on the claims involving the 
Kirson property primarily and the Singer property only to the extent relevant and 
necessary. 
 
-9- 
 
 
DATE 
RICKEY’S 
AGE 
RICKEY’S 
BLL 
CHRIS’ 
AGE 
CHRIS’ 
BLL 
 
2300 block of Barclay Street (5 April 1989 to approximately summer of 1990) 
--- 
Newborn 
--- 
--- 
--- 
 
445 East Lanvale Street (summer of 1990 to 1992) 
15 August 1990 
17 mos. 
NR 
--- 
--- 
10 April 1991 
24 mos. 
NR 
--- 
--- 
27 June 1991 
--- 
--- 
9 mos. 
7 mcg/dL 
6 February 1992 
--- 
--- 
17 mos. 
7 mcg/dL 
23 April 1992 
--- 
--- 
19 mos. 
8 mcg/dL 
 
2231 Barclay Street* (some point in 1992 to fall of 1993) 
12 January 1993 
45 mos. 
12 mcg/dL 
--- 
--- 
26 March 1993 
47 mos. 
11 mcg/dL 
--- 
--- 
13 May 1993 
--- 
--- 
32 mos. 
14 mcg/dL 
 
754 Bartlett Avenue** (fall of 1993 to 1995) 
24 September 1993 
53 mos. 
14 mcg/dL 
--- 
--- 
10 November 1993 
--- 
--- 
38 mos. 
17 mcg/dL 
26 January 1994 
--- 
--- 
41 mos. 
15 mcg/dL 
12 May 1994 
--- 
--- 
44 mos. 
15 mcg/dL 
28 October 1994 
66 mos. 
10 mcg/dL 
--- 
--- 
2 February 1995 
--- 
--- 
53 mos. 
11 mcg/dL 
11 October 1995 
--- 
--- 
61 mos. 
10 mcg/dL 
 
1504 Gorsuch Avenue (1995 to 1998) 
13 March 1996 
83 mos. 
7 mcg/dL 
--- 
--- 
 
* The 2231 Barclay house was owned by Singer. 
** The 754 Bartlett Ave. house was owned by the Kirsons and is the subject of the 
present appeal. 
Shaded blocks represent those test results which indicate elevated blood lead levels.6 
 
 
 
 
 
 
 
 
6 Blood lead levels are measured in micrograms per deciliter.  According to Dr. 
Simon’s report, a child is considered to have elevated blood lead levels at 10 mcg/dL. 
 
-10- 
 
During discovery, the Hamiltons retained Arc Environmental, Inc., to survey the 
754 Bartlett Avenue property for lead-based paint.  On 4 March 2011, Arc tested (or 
attempted to test) the property and issued a report of its findings on 9 March 2011.  
According to the report, the X-ray fluorescence analyzer detected lead-based paint, above 
the Maryland standard (>0.7 mg/cm2),7 on four of the fourteen surfaces tested—the front 
porch wall, the front window apron and casing, and the front basement window header.  
The report noted that the property is “an occupied two story brick row home.  The 
inspector knocked on the front door of the property and spoke with a female resident who 
stated that she has lived at the property for many years and subsequently denied the 
inspectors [sic] request to test the interior of the property, but allowed exterior testing.” 
Additionally, as part of discovery, the Hamiltons identified Dr. Jacalyn Blackwell-
White, a board-certified pediatrician, as a medical causation expert and Dr. Robert Simon 
as an industrial hygiene expert and environmental lead risk assessor.  Drs. Blackwell-
White and Simon authored causation reports and were deposed. 
Dr. Blackwell-White opined:  
Rickey Hamilton experienced toxic levels of lead elevation during his 
younger years.  Within a reasonable degree of medical probability, he 
suffered brain damage as a result of that exposure.  The most likely 
source/sources of Rickey’s exposure include 2231 Barclay Street and 754 
 
 
 
 
 
 
 
7 In Maryland, “lead-containing substance” is defined, in relevant part, as “any 
paint, plaster or other surface coating material containing . . . more than 0.7 milligrams 
per square centimeter by the X-ray fluorescence [‘XRF’] analyzer.”  COMAR 
26.02.07.02.  According to the Arc Environmental report, where the XRF analyzer 
provides a reading of 0.7mg/cm2 or less, the surface is classified as “negative,” and where 
the reading is above the standard, the surface is classified as “positive.” 
 
-11- 
 
Bartlett Avenue.  However, the visitation properties of 417 E. North 
Avenue and 510 E. 20th Street cannot be excluded.  There was a paucity of 
descriptive interior surface information, lead paint information and details 
about the visits included concerning these properties. 
 
With regard to Christopher Hamilton, Dr. Blackwell-White opined: 
It is my opinion that Christopher Hamilton was exposed to sustained levels 
of lead at an early age.  The possible sources of Christopher’s lead exposure 
include 445 E. Lanvale Street, 2231 Barclay Street, 754 Bartlette [sic] 
Avenue, 417 E. North Avenue and 510 E. 20th Street.  Based on the 
information available to me, more likely than not, Christopher was exposed 
to lead based paint at 2231 Barclay Street and 754 Bartlette [sic] Avenue 
because he experienced a significant rise in lead levels which was sustained 
during his residence at these two addresses.  There was no significant 
change in blood lead level after moving from 2231 Barclay Street to 754 
Bartlette [sic] Avenue.  There is not enough information available to me to 
implicate the Lanvale Street property over the visitation properties as a 
source of lead exposure for the first three lead level elevations.  It is my 
opinion that within a reasonable degree of medical probability, he sustained 
brain damage as a result of early lead exposure and that his impairment is 
lifelong. 
 
Plaintiffs asked Dr. Simon “to determine if [Rickey’s and Christopher’s] residency 
at 2231 Barclay Street and 754 Bartlett Street, Baltimore, MD, during their early 
childhood, were substantial contributing sources of lead exposure during that time 
period.”  Dr. Simon stated that the 754 Bartlett Avenue house “was built in 1920 and 
would more likely than not have had LBP [lead-based paint] based upon the age and use 
of lead paint during that time period . . . .”8  Moreover, Dr. Simon noted that the 754 
 
 
 
 
 
 
 
8 Dr. Simon opined that “[t]he age of housing is important in the assessment of 
presence of lead-based paint . . . .”  The basis for this opinion was that:  
 
the Maryland Department of Environment which presumes that chipped, 
peeling, and flaking paint in housing built before 1950 contained lead.  The 
 
 
 
 
 
 
 
 
 
 
 
 
Continued… 
 
-12- 
 
Bartlett Avenue house contained paint in deteriorated condition.  Based on that 
information, Dr. Simon concluded:  
[T]he residences at 2231 Barclay Street and 754 Bartlett Avenue, 
Baltimore, MD were the substantial, contributing locations and sources for 
elevated blood lead levels (EBLs) and lead poisoning exposure for both 
Ricky, Jr. [sic] and Christopher Hamilton during the first 6+ years of their 
childhoods.  There was no indication in the data file that any other locations 
contributed to their EBLs [elevated blood lead levels] and lead poisoning 
during this time period. 
   
After discovery was completed, the Kirsons moved for summary judgment on 
several grounds.  First, they argued that there was no Housing Code violation 
demonstrating a negligent act on the part of Defendants and, thus, Plaintiffs did not have 
an actionable negligence claim.  Specifically, the Kirsons pointed out that Plaintiffs’ 
 
 
 
 
 
 
 
Cont’d 
 
USEPA [U.S. Environmental Protection Agency] has estimated that 
housing contained lead-based paint (LBP) based upon house age as listed 
below . . . . 
 
% Containing LBP  
Built Age of Housing 
87%  
 
 
before 1940 
69%  
 
 
between 1940 to 1960 
24%  
 
 
between 1960-1978 
 
Dr. Simon referred also to a press release on a report by the Maryland Department of the 
Environment, which cited the U.S. Census Bureau as reporting that “95% of houses were 
likely to have LBP if built before 1950 and that 75% of houses were likely to have LBP if 
built between 1950 and 1978.”  See Press Release, First Lady Hon. Kathleen O’Malley, 
MDE 
Announce 
Results 
of 
Lead 
Poisoning 
Report 
(Aug. 
27, 
2010), 
http://www.mde.state.md.us/programs/PressRoom/Pages/1296.aspx (referring to the 
Maryland Department of the Environment, Childhood Blood Lead Surveillance in 
Maryland Annual Report 2009 (Aug. 2010)). 
 
 
-13- 
 
medical causation expert, Dr. Blackwell-White, stated that the blood lead levels were 
consistent with exposure to airborne lead dust.  Plaintiffs’ negligence claims, however, 
are based on violations of the Housing Code’s prohibition of peeling or chipping paint.   
Second, the Kirsons argued that summary judgment was appropriate because there 
was no direct evidence that the subject property was the source of the Hamiltons’ lead 
poisoning and, moreover, Plaintiffs’ source experts’ opinions that the Hamiltons’ blood 
lead levels were caused by exposure to lead hazards at the subject property, 754 Bartlett 
Avenue, had an insufficient factual basis.  The Kirsons maintained that, in order for the 
Hamiltons to prove that the property had lead-based paint, testing was required for the 
specific locations alleged as peeling, flaking, or chipping at the time of Plaintiffs’ 
elevated blood lead levels.  The testing undertaken by Plaintiffs, however, was only of 
locations on the exterior of the subject property.  The Hamiltons’ mother stated in her 
deposition that the exterior of the house was not in disrepair and, thus, according to the 
Kirsons, the Hamiltons failed to produce the direct evidence that they were exposed to 
hazardous lead-based paint at the subject property.   
Moreover, the Kirsons argued that the Hamiltons’ experts based their opinions of 
the source of the Hamiltons’ lead exposure on the assumption that, if the exterior of the 
house had lead paint, the interior of the house also contained lead-paint.  According to the 
Kirsons, the experts based this assumption (and, therefore, their opinions) on the age of 
the house, the condition of the house, and the age and recorded blood lead levels of the 
Hamiltons at the time of the tenancy.  Such assumptions, it was claimed, were 
insufficient to form the factual basis of an expert opinion.  Additionally, the Kirsons 
 
-14- 
 
contended that the Hamiltons’ source experts lacked a sufficient factual basis to conclude 
that the subject property was the source because they “did not rule out other potential 
sources of Plaintiffs’ blood lead levels that were recorded while they lived at [the subject 
property].”  Specifically, the Kirsons pointed out that the Hamiltons’ source experts 
failed to consider the three other properties that the Hamiltons visited frequently or lived 
in during the time period before and during their lead poisoning9 and failed to rule out 
that the blood lead levels were the result of environmental or ambient sources, even 
though both experts acknowledged that lead poisoning may be caused by these other 
sources. 
The Hamiltons filed a Response in Opposition to the Kirsons’ Motion for 
Summary Judgment, insisting that a sufficient factual basis existed to support the 
opinions of their experts.  The Hamiltons emphasized that experts are permitted to use a 
combination of direct and circumstantial evidence to support their opinions.  They 
maintained that, particularly in cases such as lead-paint poisoning, where often injured 
persons do not have the ability to obtain direct evidence through testing of the properties 
contemporaneously with their tenancy or afterwards in certain circumstances, 
 
 
 
 
 
 
 
9 According to the Kirsons, Dr. Blackwell-White acknowledged that she could not 
rule out the three visitation properties because she lacked the information necessary to 
make that determination.  Dr. Simon stated that, even though he assessed typically 
visitation properties when he performed lead risk assessments in the past, he was not 
provided with any environmental information regarding the other properties in this case. 
 
 
-15- 
 
circumstantial evidence is the only recourse.   Specifically, in this case, the Hamiltons 
stated: 
 [T]he subject property was built in 1920, circumstantially leading to a 
finding that the structure contained lead-based paint.  Both Christopher and 
Rickey Hamilton ate paint chips while living there.  During their tenancy, 
Plaintiffs’ blood lead levels remained elevated; significant because of Dr. 
Simon’s testimony regarding the half-life of lead in a person’s blood.  
Neither Plaintiff had enough contact with the visiting properties to allow 
those houses to be considered significant contributing factors.  Lastly, a 
2010 ARC Environmental test of the exterior of the property found lead-
based paint. 
 
Thus, according to the Hamiltons, “there is sufficient direct and circumstantial evidence 
to support the opinions of Dr. Blackwell-White and Dr. Simon.”  
The Circuit Court held a hearing on 10 August 2011.  After hearing argument, the 
Circuit Court stated, in pertinent part, on the record: 
I’m going to grant the motion.  I’m, you know. Actually, I guess, eventually 
we’re going to get some more on a post-Dow[10] cases from the Appellate 
Courts.  But basically, my understanding, this is not enough for the 
circumstantial evidence. . . .  [T]he Court’s not convinced that there’s 
enough circumstantial evidence under Dow and I realized that that’s 
something that, you know, as a city, eventually we’ve got some 
clarification.  But it’s my understanding that there’s sufficient, based upon 
the record here, that there’s sufficient evidence about so many other, not 
abstract sources, but very real sources, that it’s not sufficient.  So for that 
reason, I will grant the motion. 
 
On the next day, 11 August 2011, the Circuit Court entered an order granting the 
Kirsons’ Motion for Summary Judgment “for the reasons stated on the record in open 
court.” 
 
 
 
 
 
 
 
10 Dow v. L & R Props., Inc., 144 Md. App. 67, 796 A.2d 139 (2002). 
 
-16- 
 
The Hamiltons appealed timely.  On 30 April 2013, the Court of Special Appeals 
issued an unreported opinion affirming the Circuit Court’s judgment granting summary 
judgment.  We granted a Writ of Certiorari, on the Hamiltons’ petition, 433 Md. 513, 72 
A.2d 172 (2013), to consider the following questions: 
(1) Did the trial court err by refusing to allow plaintiffs’ expert witnesses to testify 
that the defendant’s property was a substantial contributing cause to plaintiffs’ 
injurious lead exposure on the grounds that they did not sufficiently rule out other 
potential sources of lead exposure?  
 
(2) Did the trial court err by granting summary judgment for defendant on the 
grounds that there was insufficient evidence as to causation?  
 
(3) Is a Dow analysis applicable to a lead paint claim involving possible exposure 
at multiple properties? 
 
C. Consolidation 
We consolidate these cases for decision because they present a common, over-
arching inquiry—under what circumstances, if any, will circumstantial evidence alone of 
the possible presence of lead-based paint inside a residential property be sufficient to 
survive a defense motion for summary judgment challenging the sufficiency of proof of 
the causation element of a negligence claim against the landlord.  There is much recent 
case law, particularly from the Court of Special Appeals, on the proof of lead paint 
poisoning causation through circumstantial evidence.  We aspire here to consider these 
cases, add our judicial gloss to them, and resolve any inconsistencies.   
II. 
STANDARD OF REVIEW 
In the present cases, the Circuit Court granted defense motions for summary 
judgment, concluding that Plaintiffs failed to produce sufficient circumstantial evidence 
 
-17- 
 
to make out a prima facie case regarding the causation element of a negligence claim.  
The Circuit Court, in granting the motions for summary judgment, rejected implicitly or 
explicitly Plaintiffs’ experts’ conclusions that the subject properties were a substantial 
contributing source of Plaintiffs’ injuries.  The Court of Special Appeals, in its 
unreported opinion in Hamilton, noted aptly the dual nature of the Circuit Court’s 
decision: 
The Hamiltons argue that the circuit court erred in granting summary 
judgment because their experts had a sufficient factual basis for their 
opinions.  They further assert that even without expert opinions, the other 
evidence was sufficient to show that the Bartlett address was a substantial 
contributing cause of their injuries.  These two arguments go hand in hand 
because the evidence that the Hamiltons presented on causation was the 
same evidence the experts used to form their opinions.  Thus, the circuit 
court decision contains two findings: 1) that the experts did not have a 
sufficient factual basis for their conclusions that the Bartlett property was a 
substantial contributing source, and 2) that the evidence the experts used as 
their factual basis was not enough to independently establish causation. 
 
Hamilton v. Kirson, No. 1530, September Term, 2011, slip op. at 14-15 (Md. Ct. Spec. 
App. April 30, 2013), cert. granted, 433 Md. 513, 72 A.2d 172 (2013).  Regardless of the 
dual nature of the decision, the case involved the grant of summary judgment and we 
review it as such.11   
 
 
 
 
 
 
 
11 It appears that the Court of Special Appeals in Hamilton v. Dackman, 213 Md. 
App. 589, 75 A.3d 327 (2013), and Taylor v. Fishkind, 207 Md. App. 121, 51 A.3d 743 
(2012), reviewed the Circuit Court’s grant of motions for summary judgment on the 
grounds of an insufficient basis for the expert’s testimony under two standards of review.  
The intermediate court reviewed the trial court’s decisions regarding the sufficiency of 
the experts’ opinions under an abuse of discretion standard, and the decisions regarding 
the summary judgment without deference.  That is not the standard to be employed.  
 
 
 
 
 
 
 
 
 
 
 
 
Continued… 
 
-18- 
 
A circuit court may grant a motion for summary judgment, entering judgment in 
favor of the moving party, “if the motion and response show that there is no genuine 
dispute as to any material fact and that the party in whose favor judgment is entered is 
entitled to judgment as a matter of law.”  Md. Rule 2-501(e).  Maryland’s summary 
 
 
 
 
 
 
 
Cont’d 
 
This Court recognizes that “in order to pass muster at a summary judgment 
proceeding, the opponent must produce evidence that would be admissible at trial.”  
Helinski v. Rosenberg, 90 Md. App. 158, 166, 600 A.2d 882, 886 rev'd, 328 Md. 664, 
616 A.2d 866, rev’d on other grounds, Rosenberg v. Helinski, 328 Md. 664, 616 A.2d 
866 (1992) (citing Gooch v. Maryland Mechanical Sys., Inc., 81 Md. App. 376, 396, 567 
A.2d 954 (1990)); see also Gooch, 81 Md. App. at 396, 567 A.2d at 954 (“facts proffered 
in opposition to the granting of a motion for summary judgment must be admissible in 
evidence”) (citations omitted).  Maryland Rule 5-702, which governs the admissibility of 
expert testimony, provides: 
 
Expert testimony may be admitted, in the form of an opinion or otherwise, 
if the court determines that the testimony will assist the trier of fact to 
understand the evidence or to determine a fact in issue. In making that 
determination, the court shall determine (1) whether the witness is qualified 
as an expert by knowledge, skill, experience, training, or education, (2) the 
appropriateness of the expert testimony on the particular subject, and (3) 
whether a sufficient factual basis exists to support the expert 
testimony.  
 
(Emphasis added.)  Accordingly, where a circuit court grants a summary judgment 
motion on the grounds that the plaintiff’s expert lacks a sufficient factual basis of 
admissible facts and the admissible evidence (if any) is insufficient independently to 
prove causation, the circuit court is making a decision on the admissibility of the expert’s 
testimony as part of its summary judgment decision and, thus, is making a legal decision.  
Such a decision is reviewed on appeal without deference, as the grant of all summary 
judgment motions are.  See, e.g., Giant Food, Inc. v. Booker, 152 Md. App. 166, 176-78, 
831 A.2d 481, 486-87 (2003) (reviewing the denial of a motion for judgment and a 
motion for judgment notwithstanding the verdict without deference, even though the 
reasoning for the trial judge’s decision was based upon the admissibility of the expert 
testimony due to an allegedly sufficient factual basis for concluding that accidental 
exposure to Freon caused the plaintiff’s asthma). 
 
-19- 
 
judgment rule makes clear that “a trial court determines issues of law; it makes rulings as 
a matter of law, resolving no disputed issues of fact.”  Beatty v. Trailmaster Products, 
Inc., 330 Md. 726, 737, 625 A.2d 1005, 1011 (1993) (citing Heat & Power v. Air 
Products, 320 Md. 584, 591, 578 A.2d 1202 (1990)).  “In this regard, the standard for 
appellate review of a trial court’s grant of a motion for summary judgment is simply 
whether the trial court was legally correct,” id. (citations omitted), and is subject to no 
deference.  Tyler v. City of Coll. Park, 415 Md. 475, 498, 3 A.3d 421, 434 (2010) 
(citations omitted). 
As such, in reviewing a grant of summary judgment, we review 
independently the record to determine whether the parties generated a 
dispute of material fact and, if not, whether the moving party was entitled to 
judgment as a matter of law. Charles County Comm'rs [v. Johnson], 393 
Md. [248,] 263, 900 A.2d [753,] 762 [(2006)]. We review the record in the 
light most favorable to the non-moving party and construe any reasonable 
inferences that may be drawn from the well-plead facts against the moving 
party. Conaway [v. Deane], 401 Md. [219,] 243, 932 A.2d [571,] 585 
[(2007)]; Charles County Comm'rs, 393 Md. at 263, 900 A.2d at 762 
Id., 415 Md. at 498-99, 3 A.3d at 434. 
 
That our appellate review is premised on assumptions favoring the non-moving 
party does not mean that the party opposing the motion for summary judgment prevails 
necessarily.  Rather, 
in order to defeat a motion for summary judgment, the opposing party must 
show that there is a genuine dispute as to a material fact by proffering facts 
which would be admissible in evidence.  Consequently, mere general 
allegations which do not show facts in detail and with precision are 
insufficient to prevent summary judgment.   
. . . 
[T]he mere existence of a scintilla of evidence in support of the plaintiffs' 
claim is insufficient to preclude the grant of summary judgment; there must 
be evidence upon which the jury could reasonably find for the plaintiff.  
 
-20- 
 
Anderson [v. Liberty Lobby, Inc.,] 477 U.S. [242,] 252, 106 S. Ct. [2505,] 
2512 [(1986)].  We recognized in Clea v. City of Baltimore, 312 Md. 662, 
678, 541 A.2d 1303 (1988), that while a court must resolve all inferences in 
favor of the party opposing summary judgment, “[t]hose inferences ... must 
be reasonable ones.” (Emphasis in original.) In that case, we quoted 
Professor Wright, as follows: 
“It is frequently said that summary judgment should not be 
granted if there is the ‘slightest doubt’ as to the facts. Such 
statements are a rather misleading gloss on a rule that speaks 
in terms of ‘genuine issue as to any material fact,’ and would, 
if taken literally, mean that there could hardly ever be a 
summary judgment, for at least a slight doubt can be 
developed as to practically all things human. A better 
formulation would be that the party opposing the motion is to 
be given the benefit of all reasonable doubts in determining 
whether a genuine issue exists.” 
312 Md. at 678, 541 A.2d 1303, quoting C. Wright, The Law of Federal 
Courts § 99, at 666-667 (1983). 
 
Beatty, 330 Md. at 737-39, 625 A.2d at 1011-12 (some internal citations omitted).  
Furthermore, “it is a settled principle of Maryland appellate procedure that ordinarily an 
appellate court will review a grant of summary judgment only upon the grounds relied 
upon by the trial court.”  Bishop v. State Farm, 360 Md. 225, 234, 757 A.2d 783, 787 
(2000); see also Lovelace v. Anderson, 366 Md. 690, 695-96, 785 A.2d 726, 729 (2001). 
III. 
DISCUSSION 
Generally, “[t]o state a claim for negligence a party must show ‘1) that the 
defendant was under a duty to protect the plaintiff from injury, 2) that the defendant 
breached that duty, 3) that the plaintiff suffered actual injury or loss, and 4) that the loss 
or injury proximately resulted from the defendant’s breach of the duty.”  Taylor v. 
Fishkind, 207 Md. App. 121, 148, 51 A.3d 743, 759 (2012) (quoting Rosenblatt v. Exxon 
Co., U.S.A., 335 Md. 58, 76, 642 A.2d 180 (1994)).  Where an applicable statutory 
 
-21- 
 
scheme is designed to protect a class of persons which includes the plaintiff, “the 
defendant’s duty ordinarily ‘is prescribed by the statute’ or ordinance and . . . the 
violation of the statute or ordinance is itself evidence of negligence.”  Brooks v. Lewin 
Realty III, Inc., 378 Md. 70, 78, 835 A.2d 616, 620 (2003) (quoting Brown v. Dermer, 
357 Md. 344, 358-59, 744 A.2d 47, 55 (2000), overruled in part on other grounds by 
Brooks, 378 Md. at 72, 835 A.2d at 617).   
This Court set out in Brooks the requirements for a plaintiff to make out a prima 
facie showing in a statutory violation lead paint poisoning negligence action: 
[I]n order to make out a prima facie case in a negligence action, all that a 
plaintiff must show is: (a) the violation of a statute or ordinance designed to 
protect a specific class of persons which includes the plaintiff, and (b) that 
the violation proximately caused the injury complained of.  Proximate 
cause is established by determining whether the plaintiff is within the class 
of persons sought to be protected, and the harm suffered is of a kind which 
the drafters intended the statute to prevent. . . . It is the existence of this 
cause and effect relationship that makes the violation of a statute prima 
facie evidence of negligence. 
378 Md. at 79, 835 A.2d at 621 (internal quotation marks and citation omitted).  Once a 
plaintiff makes out a prima facie case in negligence, i.e., where he or she produces 
“evidence that the violation of the statute proximately caused the plaintiff’s injury,” such 
evidence is sufficient so as to “‘warrant the court in submitting the case to the jury on the 
question of the [defendant’s] negligence.’”12  Id. (alterations added in Brooks) (quoting 
 
 
 
 
 
 
 
12 In several other jurisdictions, plaintiffs in lead paint poisoning negligence 
actions are required additionally to adduce evidence that the tort defendant had 
knowledge that he or she violated the statute.  In Maryland, however, Brooks makes clear 
that “once it is established that there was a statutory violation, the tort defendant’s 
 
 
 
 
 
 
 
 
 
 
 
 
Continued… 
 
-22- 
 
Crunkilton v. Hook, 185 Md. 1, 4, 42 A.2d 517, 519 (1945)).  Then, “[t]he trier of fact 
must . . . evaluate whether the actions taken by the defendant were reasonable under all 
the circumstances.”  Id. (citations omitted).13 
 
In the present cases, the plaintiffs relied upon violations of the City Housing 
Code14 to establish the landlord’s or homeowner’s prima facie negligence.  In Brooks, we 
summarized that, to establish a prima facie negligence case for lead-paint poisoning 
based on violation of the Housing Code, a plaintiff must show that there was flaking, 
loose, or peeling paint: 
In sum, the presence of flaking, loose, or peeling paint is a violation of the 
Housing Code.  Brown v. Dermer, 357 Md. at 361, 744 A.2d at 56-57 (“To 
be a violation, all that must be shown is that there was flaking, loose or 
peeling paint”).  As earlier pointed out, certain provisions of the Housing 
Code were clearly enacted to prevent lead poisoning in children.  Therefore, 
the plaintiff . . . is in the class of people intended to be protected by the 
Housing Code, and his injury, lead poisoning, is the kind of injury intended 
to be prevented by the Code.  This is all that the plaintiffs must show to 
establish a prima facie case sounding in negligence.  Therefore, the notices 
of violation issued to Lewin Realty by the Department of Housing for 
 
 
 
 
 
 
 
Cont’d 
 
knowledge that he or she violated the statute is not part of the tort plaintiff’s burden of 
proof.  It is the violation of the statute or ordinance alone which is evidence of 
negligence.”  Brooks v. Lewin Realty III, Inc., 378 Md. 70, 80, 835 A.2d 616, 622 (2003) 
(emphasis added). 
 
13 In this sense, contrary to the contentions of the Respondents in Alston, prima 
facie negligence differs from strict liability, which does not permit a defendant to explain 
how his actions were reasonable. 
 
14 Specifically, as noted earlier in this opinion, the plaintiffs relied on Housing 
Code, Baltimore City Code (2000 Repl. Vol.), Art. 13, § 702, 703, & 706.  See supra note 
2. 
 
-23- 
 
unrelated properties were irrelevant and there should be a new trial as 
directed by the Court of Special Appeals. 
 
378 Md. at 89, 835 A.2d at 627 (footnote omitted). 
 
Although peeling, chipping, or flaking paint (of any kind) constitutes a violation of 
the Housing Code, such a Code violation permits merely an inference of prima facie 
negligence on the part of the homeowner or landlord.  Such an inference, however, does 
not eliminate the requirement that the plaintiff prove that the landlord’s negligence 
caused proximately the injury.  As the Court of Special Appeals explained in Hamilton v. 
Dackman, 213 Md. App. 589, 613, 75 A.3d 327, 340-41 (2013) (hereinafter, “Raymond 
Hamilton”), “although the Court of Appeals suggested in Brooks that a statutory 
violation may constitute a prima facie case of negligence, 378 Md. at 79, 835 A.2d 616, 
that holding does not relieve a plaintiff of the obligation to establish causation.”  More 
specifically, the intermediate appellate court stated: 
Brooks eliminated notice of a lead-paint violation as one element of a 
negligence claim. 378 Md. at 72, 835 A.2d 616. The Court of Appeals 
explained that the plaintiffs did not have to provide notice and could submit 
their claim to the jury without proving that the landlord had notice “if the 
plaintiffs can establish a violation of the Housing Code which proximately 
caused [plaintiff's] injuries.” Id. at 81, 835 A.2d 616 (emphasis added). 
This meant, in Brooks, that where a child had been seen chewing repeatedly 
on a windowsill in a home that upon later inspection specifically was found 
to contain lead-based paint, id. at 73–74, 835 A.2d 616 (and whom the 
record did not reflect lived or visited any property other than the one that 
was the subject of the litigation), she could submit her case to the jury 
without having to show that the defendant had notice of the condition. Id. at 
72, 835 A.2d 616; see also Polakoff v. Turner, 385 Md. 467, 483, 869 A.2d 
837 (2005) (permitting the plaintiff to submit her case to the jury if she 
“could establish a violation of the Code which proximately caused her 
injuries” (emphasis added)). 
 
Raymond Hamilton, 213 Md. App. at 613, 75 A.3d at 341 (emphasis added in original).  
 
-24- 
 
In the present cases, because we elect to resolve the cases on the issue of 
causation, we accept the premise that the subject properties were afflicted with peeling, 
chipping, or flaking paint.  Accepting such premise, the Hamiltons and the Alstons made 
out prima facie cases that the defendants—the owners and/or landlords of the 
residences—committed negligent acts in violation of the Housing Code.  Thus, we 
address what quality or quantum of circumstantial evidence of causation is sufficient to 
make out a prima facie showing for that element of the negligence case. 
A. Causation Analysis in Maryland Lead Paint Cases 
“It is fundamental that in a negligence action the plaintiff has the burden of 
proving all the facts essential to constitute the cause of action.”  Peterson v. Underwood, 
258 Md. 9, 15, 264 A.2d 851, 854 (1970).  One element of a negligence case is that the 
defendant’s negligence was a proximate cause of the accident or injury.  See, e.g., 
Raymond Hamilton, 213 Md. App. at 613, 75 A.3d at 341.  The inquiry here focuses on 
“causation in fact,” one aspect of proximate cause, “concerned with the more 
fundamental (and some have thought metaphysical) inquiry of whether defendant’s 
conduct actually produced an injury.”  Peterson, 258 Md. at 16-17, 264 A.2d at 855. 
We have recognized repeatedly that a plaintiff may prove causation in fact through 
circumstantial evidence, as well as direct evidence or a mixture of the two.  For example, 
in Peterson, the Court stated: 
If lay testimony together with reasonable inferences does not directly show 
this causal relation (such as a witness's observing a brick hurled through a 
plate glass window) it may be shown in a number of other ways. The most 
familiar method today is through the opinion of the expert who states that, 
based on facts in evidence, X was the efficient cause of the injury. Such 
 
-25- 
 
opinion testimony is not always required, and the plaintiff produces legally 
sufficient proof to get to the jury once he shows it is more probable than not 
that defendant's act caused his injury. This does not mean plaintiff is 
required to exclude every other possible cause of the accident. But where 
plaintiff by his own evidence shows two or more equally likely causes of 
the injury, for only one of which defendant is responsible, plaintiff can not 
recover. The situation before us is somewhat analogous, except that instead 
of showing two evenly balanced probable causes, plaintiff has shown none. 
 
In the trial below plaintiff apparently relied on an inference that defendants' 
acts were the cause or proximate cause of the injury. An ‘inference’ is a 
deduction or conclusion which reason and common sense lead a jury to 
draw from the facts proved. United States v. Schneiderman, 106 F. Supp. 
906, 928 (S. D. Cal. 1952), cf. 21 Words and Phrases, ‘inference’ (1960). 
This attempted reliance amounts to proof of causation by 
circumstantial rather than direct evidence. In accordance with the 
general rules stated above, this type of evidence is not inherently 
insufficient; all that is necessary is that it amount to a reasonable 
likelihood or probability rather than a possibility. 
 
258 Md. at 17, 264 A.2d at 855 (emphasis added) (some internal citations omitted).   
 
When a plaintiff does not offer a direct explanation of the cause of the injury or 
accident, a plaintiff is “compelled to rely entirely on the inference.”  Peterson, 258 Md. at 
18-19, 264 A.2d at 856.  The validity of an inference “depends on commonly experienced 
relationships of acts and forces,” id., 258 Md. at 18, 264 A.2d at 856, or “depends on 
logical deduction from an established fact.”  Id., 258 Md. at 19, 264 A.2d at 856.  Certain 
sets of facts may make an inference less valid than other sets of facts.  See, e.g., id., 258 
Md. at 21, 264 A.2d at 857 (concluding that the passage of time between the negligent act 
and the injury rendered the inference of causation illogical and thus concluded that the 
trial court’s granting of summary judgment was proper).  The conclusion that an 
inference is not valid due to a lack of supporting facts or an articulable logical 
relationship does not mean that we place greater weight on direct evidence than on 
 
-26- 
 
circumstantial evidence.  Rather, it means that we require inferences to be sound 
logically, and we refuse to allow a jury of laymen to engage in “‘guesswork, speculation 
and conjecture.’”  Id., 258 Md. at 21, 264 A.2d at 857 (quoting Wilhelm v. State Traffic 
Safety Comm., 230 Md. 91, 101, 185 A.2d 715, 719 (1962)). 
In the context of lead paint cases, this Court’s next most recent decision on 
causation is Ross v. Housing Authority of Baltimore City, 430 Md. 648, 63 A.3d 1 (2013).  
In Ross, the Court recognized aptly that, in the typical lead-paint case,15 the theory of 
causation has multiple analytical layers: 
 The theory of causation presented in this case can be conceived of as a 
series of links: (1) the link between the defendant's property and the 
plaintiff's exposure to lead; (2) the link between specific exposure to lead 
and the elevated blood lead levels, and (3) the link between those blood 
lead levels and the injuries allegedly suffered by the plaintiff. To be a 
substantial factor in causing Ms. Ross' alleged injuries, the Payson Street 
home must have been a source of Ms. Ross' exposure to lead, that exposure 
must have contributed to the elevated blood lead levels, and the associated 
increase in blood lead levels must have been substantial enough to 
contribute to her injuries. 
 
Ross, 430 Md. at 668, 63 A.3d at 12-13 (emphasis added) (footnote omitted).  In the 
present cases, we are concerned with the first link.  To prove this link, circumstantial 
evidence may be used, “so long as it creates ‘a reasonable likelihood or probability rather 
 
 
 
 
 
 
 
15 In reiterating this multi-level causation approach, we repeat also the admonition 
in Ross: “We do not mean to rule out the possibility of other ways that a plaintiff might 
demonstrate that lead exposure is a substantial factor in a resulting harm to an 
individual.”  430 Md. at 668 n.20, 63 A.3d at 13 n.20.  In these consolidated cases, 
however, both sets of plaintiffs relied on the same causation theory as in Ross.  Thus, we 
do not dwell on hypotheticals beyond those deemed necessary to clarify or illuminate the 
law. 
 
-27- 
 
than a possibility’ supporting a ‘rational inference of causation,’ and is not ‘wholly 
speculative.’”  West, 212 Md. App. at 170-71, 66 A.3d at 1150 (citations omitted).  The 
Hamiltons’ and Alstons’ cases hinge on that fine distinction between circumstantial 
evidence that amounts to a reasonable likelihood or probability and circumstantial 
evidence that amounts only to a possibility and speculation.   
To connect the dots between a defendant's property and a plaintiff's exposure to 
lead, the plaintiff must tender facts admissible in evidence that, if believed, establish two 
separate inferences: (1) that the property contained lead-based paint, and (2) that the lead-
based paint at the subject property was a substantial contributor to the victim’s exposure 
to lead.  At times, these separate inferences may be drawn from the same set of facts, but 
parties would do well to remember that these inferences are separate and often will 
require different evidentiary support. 
In an effort to contribute to clarification of any confusion, we consider first Dow v. 
L & R Properties Inc., 144 Md. App. 67, 796 A.2d 139 (2002), which represents a 
scenario where multiple inferences seek to draw succor from the same factual reservoir: 
In [Dow], a child and her mother sued their landlord for injuries the child 
allegedly suffered as a result of ingesting lead paint in their home. The 
discovery materials and an affidavit of the mother indicated that the home 
had been built prior to 1950 and thus likely had lead paint, that there was 
chipping and peeling paint in areas where the child played and that the 
child placed paint chips in her mouth, that the child spent most of her time 
in the home while she lived there and did not have contact with other 
sources of lead during that period, and that the child developed lead 
poisoning. 
 
The landlord in Dow moved for summary judgment, arguing that (1) the 
plaintiff had not identified an expert who would testify that there was lead 
paint on the premises and (2) there was no other direct evidence that the 
 
-28- 
 
paint contained lead. As a result, the landlord argued, there was insufficient 
evidence to prove causation and the landlord was entitled to judgment as a 
matter of law. The Court of Special Appeals rejected that argument and 
concluded that the circumstantial evidence was sufficient to generate a 
genuine issue of material fact and thus defeat the landlord's motion for 
summary judgment. 144 Md. App. at 74–75, 796 A.2d 139. The court 
reasoned that it was not necessary for the plaintiff to prove causation by 
direct evidence; circumstantial evidence that “amounts to a reasonable 
likelihood or probability rather than a possibility” would suffice. Id. 
(quoting Peterson v. Underwood, 258 Md. 9, 17, 264 A.2d 851 (1970)). 
The court held that evidence offered by the plaintiff in opposition to the 
motion, if believed by the fact-finder, could support an inference that the 
property was the only possible source of the child's lead poisoning. Id. at 
76, 796 A.2d 139. 
 
Ross, 430 Md. at 669-70, 63 A.3d at 13 (summarizing Dow). 
In sum, the facts in Dow showed that (1) the child victim spent most of her time at 
the subject property where she lived and did not have contact with other possible sources 
of lead during the relevant period; (2) the child was observed ingesting regularly flaking 
or chipping paint at that property; (3) the child played frequently in the area of the flaking 
or chipping paint; and (4) the child had high blood lead levels during that time period, 
i.e., developed lead poisoning.  The court concluded that, under those circumstances, 
there was more than a mere possibility that the house where the child resided and spent 
most of her time was the only possible source of the lead exposure.  As such, because the 
child spent almost all of her time at the house, the court concluded additionally that it was 
more than a mere possibility that the house contained lead-based paint.  Even though 
there was no direct evidence of lead at that property, i.e., no scientific testing, it was 
reasonable to infer that there had to be lead at that property because the child would not 
have suffered otherwise from lead poisoning.  In that sense, the plaintiff eliminated all 
 
-29- 
 
other possible sources of lead poisoning in order to make reasonable and probable those 
conclusions.  Thus, the court drew two necessary, separate inferences on the basis of the 
same set of facts. 
In a very instructive case, Ross, this Court found, in reviewing the grant of 
summary judgment in favor of defendants, that a reasonable inference would be “that the 
lead investigation reports for the [plaintiffs’] home accurately identified lead on the 
property.”  430 Md. at 670, 63 A.3d at 14.  The Ross Court detailed the facts supporting 
this inference:  
The 1992 inspection returned positive results for exterior lead as well as 
“surface dust” on the interior. The 1994 inspection again indicated the 
presence of lead on exterior walls. The only direct evidence of an indoor 
source of lead was the 2009 ARC [E]nvironmental survey that indicated the 
presence of lead on an interior stair riser, though it is not indicated in the 
record whether that location was tested earlier or whether it was in a 
deteriorating condition in the early 1990s. 
 
Ross, 430 Md. at 671 n.23, 63 A.3d at 14 n.23.16  As such, Ross and Dow are examples of 
cases with sufficient circumstantial evidence for the drawing of separate and reasonable 
inferences of the presence of lead at the subject property. 
 
 
 
 
 
 
 
16 In Ross, the Circuit Court refused to let the case go to the fact-finder in the 
absence of an expert’s admissible testimony.  We held, however, that an expert was not 
necessary to connect the dots between the lead on the property and the child’s exposure 
to lead and, therefore, remanded the case to the Circuit Court.  We cautioned:  
 
[I]t may well be that, once the parties have marshaled the evidence without 
the expert opinion on source, it is clear which facts are disputed and which 
are not, and the limits of the inferences in plaintiff’s favor are evident, 
summary judgment might still be warranted. 
 
 
 
 
 
 
 
 
 
 
 
 
 
Continued… 
 
-30- 
 
The present cases, in contrast, lack the same or similar quality of circumstantial 
evidence undergirding the desired inferences.  Despite this difference, Plaintiffs here 
cling to the same theory of causation advanced by the plaintiffs in Dow.  Specifically, 
Plaintiffs ask this Court to permit a fact-finder to draw multiple inferences from a 
singular group of facts, even though Plaintiffs failed to exclude other potential sources of 
lead in these cases.  Moreover, Plaintiffs declined to use seemingly available judicial 
methods17 for testing the interior of the houses.18  We have yet to address this scenario, 
 
 
 
 
 
 
 
Cont’d 
 
Ross, 430 Md. at 671, 63 A.3d at 14. 
 
17 For example, where a defendant owns still the subject property, Md. Rule 2-
422(a) supplies a mechanism for the inspection and testing of the property for the 
presence of lead-based paint, providing in pertinent part: “[a]ny party may serve one or 
more requests to any other party . . . (2) to permit entry upon designated land or other 
property in the possession or control of the party upon whom the request is served for the 
purpose of inspection, measuring, surveying, photographing, testing, or sampling the 
property . . . .”  See also Butler v. S & S P’ship, 435 Md. 635, 645-49, 80 A.3d 298, 305-
07 (2013) (discussing the application of this Rule in-depth). 
In contrast, though, in those lead-paint cases in which the defendant is a former 
owner and a different person or entity owns the subject property at the time of the 
litigation, such as the present cases, the plaintiffs may not avail themselves of Md. Rule 
2-422.  See Webb v. Joyce Real Estate, Inc., 108 Md. App. 512, 517 n.2, 672 A.2d 660, 
662 n.2 (1996) (concluding that Md. Rule 2-422 did not authorize entry onto property 
owned by a nonparty because, under Rule 2-422, “nonparties may not be compelled to 
submit to an inspection of their property”).  The Court of Special Appeals made clear in 
Stokes v. 835 N. Washington Street, LLC, 141 Md. App. 214, 784 A.2d 1142 (2001), 
however, that a plaintiff so situated may have other judicial avenues through which he or 
she may seek testing of the interior of a house owned by a non-party.   
In Stokes, the defendant was the former owner of the subject property.  The current 
owner of that property refused the plaintiffs’ request for access to that property in order 
to conduct a test for the presence of lead-based paint.  The plaintiffs filed an action 
against the current owner, seeking an order for entry upon the property to conduct a 
 
 
 
 
 
 
 
 
 
 
 
 
Continued… 
 
-31- 
 
but the Court of Special Appeals addressed it in West v. Rochkind, 212 Md. App. 164, 66 
A.3d 1145 (2013), and Hamilton v. Dackman, 213 Md. App. 589, 75 A.3d 327 (2013).  
We consider those cases now. 
 
 
 
 
 
 
 
Cont’d 
 
“noninvasive and nondestructive test” on the paint in the interior of the residence.  The 
Circuit Court denied that motion.  Plaintiffs appealed.   
The Court of Special Appeals recognized that the plaintiffs were not permitted 
under Md. Rule 2-422 to enter onto the property owned by a non-party, and that no other 
Maryland rule provided explicitly for the circuit court to grant such relief.  Despite the 
absence of a rule, however, the court held that the plaintiffs were permitted to request 
such relief from the circuit court, and “the circuit courts have the power to order 
inspection of a non-party’s property on a case-by-case basis through the equitable bill of 
discovery.”  Stokes, 141 Md. App. at 221, 784 A.2d at 1146-47. The intermediate 
appellate court reasoned that “the absence of a rule expressly authorizing an inspection 
does not preclude the circuit court from granting that relief when it is in the interest of 
justice to do so.”  Id., 141 Md. App. at 222, 784 A.2d at 1147-48.  
 
18 We recognize that practical difficulties may preclude a plaintiff from testing the 
interior of a dwelling, particularly if the home has been razed since the victim ceased 
living there.  In the present cases, however, we have no evidence of any grave difficulty 
that would have precluded Plaintiffs from obtaining testing.  In Alston, there is no 
evidence that Plaintiffs made any attempt to test the exterior or the interior of the home 
alleged to be a source of Plaintiff’s injuries.  In Hamilton, Plaintiffs hired a lead 
investigator to test the relevant subject property.  When the investigator arrived at the 
home, the current resident permitted the investigator to test only the exterior of the house, 
but would not permit him to enter for testing.  Even in Hamilton, however, there is no 
evidence in the record that Plaintiffs attempted to use judicial devices to obtain testing of 
the interior. 
We note the lack of direct evidence not because it is required per se.  We note it in 
response to the Hamiltons’ and the Alstons’ arguments that to require more evidence than 
Plaintiffs presented in these cases is an “insurmountable burden” for lead-paint plaintiffs 
generally.  Without evidence that Plaintiffs exhausted reasonable avenues to gather direct 
or circumstantial evidence of the presence of lead paint, we find it impossible to conclude 
that this standard is “insurmountable.”  Moreover, this Court acknowledged in many 
negligence cases that some cases simply do not have enough information to hold the 
defendant to trial.  In this regard, an “insurmountable burden” is appropriate for cases that 
would leave the jury to guesswork and speculation. 
 
-32- 
 
In West, the plaintiff alleged that he sustained injuries from ingesting chipping and 
flaking paint while living with his grandmother in a property owned and leased out by the 
defendants.  West’s negligence claim was based on circumstantial evidence because the 
property, since razed, had not been the subject of lead testing.  The defendants filed a 
motion for summary judgment, which the Circuit Court for Baltimore City granted, 
concluding that West failed to make out a prima facie negligence case because, unlike in 
Dow, West’s mother stated during deposition that West either resided or spent substantial 
amounts of time at a variety of houses during the first six years of his life, during which 
he experienced lead poisoning.  The Circuit Court reasoned that, in light of West’s 
“uncertain residential history and the lack of any direct evidence that [the subject 
property owned by the defendants] ever contained lead paint, [West] could not point to 
[the subject property] as the source of his lead poisoning.”  West, 212 Md. App. at 166, 
66 A.3d at 1146. 
On appeal, the Court of Special Appeals agreed.  The intermediate appellate court 
acknowledged that “[a] lead paint plaintiff may, of course, establish a prima facie case of 
negligence based solely on circumstantial evidence.”  West, 212 Md. App. at 175, 66 
A.3d at 1151.  For example, the court cited Dow, in which there was also no direct 
evidence that lead paint was present at the subject property.  The court distinguished 
Dow, however, on the grounds that “the process of elimination showed ineluctably that 
[the subject property] had to have been (not could have been, but had to have been), a 
place containing lead paint.”  Id., 212 Md. at 172, 66 A.3d at 1149.  The West court 
explained: 
 
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The evidence showed indisputably that the only place where she could have 
been exposed to lead paint was at [the subject property].  There was only 
one possible cause for the undisputed effect [because deposition testimony 
indicated that the plaintiff did not live or spend substantial time at any other 
property].  By process of elimination, there was no other possible source of 
exposure.  That, we held, constituted solid circumstantial evidence that the 
house contained lead paint . . . . 
 
Id., 212 Md. at 172, 66 A.3d at 1149-50. 
 
That the facts in Dow permitted the court to derive two analytic steps from a 
singular set of facts, the West court cautioned, “should not obscure the fact that there was 
still involved a two-step analytic process, and that what may be said about one step in 
that analytic process does not necessarily apply to the other step.”  West, 212 Md. App. at 
173, 66 A.3d at 1150.  Reiterating, the necessary two-steps are (1) the plaintiff must show 
first that the subject property had lead-based paint, and (2) then the plaintiff must show 
that his or her exposure at the subject property “was an effective cause of his lead 
poisoning.”  Id.  According to the West court, the second step, “[t]he proof of ultimate 
causation[,] does not demand exclusivity.”  Id.  The first step, the proof that the subject 
property had lead paint, however, does demand exclusivity.  Id. 
 
Based on the distinction between the proof required to satisfy these two steps, the 
West court concluded that “where no direct evidence that [the subject property] even 
contained lead paint, [West] may only rely on that critical fact, as a necessary part of his 
circumstantial evidence, if he can show by the process of elimination that [the subject 
property] was the only possible cause for the critical effect of lead poisoning.” West, 212 
Md. App. at 175, 66 A.3d at 1151.  In other words, “[the court] may only infer the 
existence of lead paint at [the subject property] from [West]’s condition if lead paint at 
 
-34- 
 
[the subject property] is shown to have been the only possible explanation for [West]’s 
condition.”  Id.  To expound on this “subtle,” “critical” distinction, the West court 
explained further: 
The distinction that Dominique [the victim] fails to grasp is a subtle one; it 
is nonetheless a critical one. In Dominique's forensic syllogism, his 
conclusion of ultimate liability does not, to be sure, depend upon the 
exclusivity of 1814 Lorman Street as a source of his lead poisoning. 
Lorman Street could readily share liability with two or three other places of 
exposure. That, however, is not the point. Before even getting to a 
syllogism's conclusion, one must first establish the premises out of which 
the conclusion arises. A necessary premise in this case is that there was, 
indeed, lead paint at 1814 Lorman Street. It is with respect to that 
antecedent premise, not with respect to the ultimate conclusion, that the 
lack of exclusivity is Dominique's Waterloo. It is the teaching of Dow that, 
even in the absence of direct proof, the presence of lead paint at a particular 
site can be inferred by the process of elimination, but only if we have 1) the 
effect of lead poisoning in the plaintiff and 2) the fact that the site in 
question was the exclusive possible source of the plaintiff's lead paint 
exposure. It was the truth of that premise that Dominique failed to establish 
in this case, not the validity of the conclusion proceeding from the 
premises. Exclusivity was not required at B. It was required at A, before 
one even gets to B. 
 
West, 212 Md. App. at 175-76, 66 A.3d at 1151-52. 
 
We agree with the West court’s analysis for application to those cases where a 
plaintiff relies on a Dow theory of causation.  Under a Dow theory of causation, a 
plaintiff must rule out other reasonably probable sources of lead exposure in order to 
prove that it is probable that the subject property contained lead-based paint.  Where the 
plaintiff fails to rule out other reasonably probable sources, the necessary inferences for a 
Dow theory of causation cannot be drawn with sufficient validity to allow the claim to 
survive summary judgment.  See also Taylor, 207 Md. App. at 136, 150, 51 A.3d at 752, 
760-61 (concluding that the trial court granted aptly the defense motion for summary 
 
-35- 
 
judgment on the grounds that “[t]he evidence in this case does not come close to the kind 
of circumstantial evidence that the Court found sufficient in Dow and that . . . it’s not 
simply the age of the house and even the peeling”).  That certain facts are missing to 
establish a Dow theory of causation, however, does not mean that the lead-poisoned 
plaintiff has no way to prove circumstantially a prima facie negligence case.  To the 
extent that West suggests that a lead-paint plaintiff must exclude all other sources of lead 
exposure in every instance of circumstantial proof, we do not agree necessarily with that 
conclusion.  
 
A lead-paint poisoned plaintiff may prove circumstantially that the subject 
property contained lead-based paint in a number of ways.  As discussed above, if a 
plaintiff is able to exclude other reasonably probable sources of lead, such as in Dow, 
then the plaintiff presents a prima facie case.  By way of another example, consider this 
illustration representing a traditional short series of row houses in Baltimore:  
 
 
 
In this hypothetical, row house “B” is the subject property (designated with the “X”) that 
a plaintiff hopes to prove, through circumstantial evidence, contains lead-based paint.  
Perhaps the row house was razed, however, and direct testing is impossible at the time of 
Row house “B” =  
subject property that a plaintiff 
wishes to prove contains lead-based 
paint. 
 
Row house “A” and “C” = 
properties 
that 
tested 
positive 
previously for lead on the interior  
 
Row house “D” = 
unknown if property contains lead 
 
-36- 
 
the litigation.  There exists, however, evidence that these four row houses were built at 
the same time in the 1920’s and that they were owned as a group by a series of persons or 
entities through the 1950’s.  Moreover, the City’s records reveal that row houses “A” and 
“C” (designated with stripes) tested positive previously for lead paint on the interior of 
the houses.  Thus, in this hypothetical (at least in the absence of evidence of lead 
abatement measures), the plaintiff is able to present circumstantial evidence from which a 
jury could infer reasonably that the subject property contained lead-based paint—without 
having to exclude all other sources of potential exposure to lead-paint poisoning.19  
 
Where a plaintiff who does not produce evidence to support another theory of 
causation and, instead, relies on a causation theory similar to that espoused in Dow, the 
validity of the necessary inference is limited to those circumstances where the plaintiff is 
able also to exclude other reasonably probable sources of lead exposure.   
B. Bridging the Inference Link with Expert Testimony 
Plaintiffs in the present cases argue that their experts’ testimony bridged any 
evidentiary gap in their circumstantial proof.  Specifically, their experts opined that the 
subject properties were probably a substantial contributor to Plaintiffs’ injuries.   
The Court of Special Appeals addressed a similar contention in Raymond 
Hamilton, 213 Md. App. 589, 75 A.3d 327.  In that case, the plaintiff lived at three leased 
dwellings: (1) a house on Gilmor Street from birth until 1993; (2) a house on Harlem 
Avenue from 1993 to 1995; and (3) a house on Fulton Avenue from 1995 to 1999.  None 
 
 
 
 
 
 
 
19 This illustration only forges one of the Ross links.  
 
-37- 
 
of those houses, however, was the subject of Raymond’s claim of lead poisoning, but 
rather a property on Appleton Street, the home of the plaintiff’s father, where the plaintiff 
visited often and stayed sometimes overnight. 
During discovery in Raymond Hamilton, the plaintiff presented a report of the 
results of a technician’s lead testing on eight exterior surfaces of the Appleton property.  
Of the eight areas tested, only one—the rear exterior door transom—tested positive for 
the presence of lead paint.  Additionally, the plaintiff identified two experts: Dr. Robert 
K. Simon, Ph.D., a chemist and industrial hygienist (the same expert as appears in 
Hamilton v. Kirson), and Dr. Jacalyn Blackwell-White, M.D., a board-certified 
pediatrician (the same expert as appears in Ross, 430 Md. at 656, 63 A.3d at 5, as well as 
in Hamilton v. Kirson).  The Court of Special Appeals described Dr. Simon’s opinion as: 
 [Dr. Simon] opined that the Appleton Street property was a source of [the 
plaintiff’s] exposure to lead-based paint.  He assumed from the age of the 
Appleton Street property that it contained lead-based paint (invoking Md. 
Code Regs. 26.16.01.03(A) (2013)).[20]  When asked to describe the basis 
for his opinion that the Appleton Street property contained lead-based 
paint, Dr. Simon admitted that he assumed the presence of lead both there 
and at the Harlem Avenue property from the properties’ age . . . . 
 
Raymond Hamilton, 213 Md. App. at 595-96, 75 A.3d at 330.   
 
Dr. Blackwell-White “opined that the Appleton Street, Harlem Avenue, and 
Fulton Avenue properties all were sources of lead-based paint and that [the plaintiff]’s 
 
 
 
 
 
 
 
20 The regulation provides: “The presence of a lead-containing substance is 
presumed in any residential building constructed before 1950 unless a person determines 
that all painted surfaces are lead-free in accordance with § B of this regulation.”  Md. 
Code Regs. 26.16.01.03(A) (2013). 
 
-38- 
 
injuries were caused by exposure at the sites . . . .”  Id., 213 Md. App. at 597, 75 A.3d at 
331.  She explained, in part: “Both properties [the Appleton Street and Harlem Avenue 
properties] were old and in the absence of physical lead assessment information, are 
presumed to have contained lead based paint.”  Id.  During a deposition of Dr. Blackwell-
White, defense counsel asked repeatedly whether Dr. Blackwell-White could rule out the 
other properties as a contributing source.  Dr. Blackwell-White replied that she could not.  
When she was asked what was the basis of her opinion, she stated: “That [the Harlem 
Avenue property] too, was an older property in disrepair.  And it was the property of 
residence when the elevated lead levels were found.” Id., 213 Md. App. at 600, 75 A.3d 
at 333. 
Dackman moved for summary judgment, arguing (1) that the plaintiff “had failed 
to provide either direct or circumstantial evidence demonstrating the presence of lead at 
the Appleton Street property during the relevant time period, and (2) that he could not 
rule out other properties as potential sources.”  Id.  In particular, “Dackman also claimed 
that because Raymond’s experts admitted they were unable to rule out other sources of 
lead exposure or other properties as containing lead, they lacked an adequate factual basis 
to conclude that the Appleton Street property was the source of his lead exposure.”  Id., 
213 Md. App. at 600-01, 75 A.3d at 333 (emphasis in original). 
The plaintiff retorted that there was abundant evidence:   
He argued that the Arc Report’s single positive test demonstrated he was 
exposed to lead at the Appleton Street property.  And he claimed that this 
evidence coupled with the testimony of his experts established a prima 
facie case that the Appleton Street property was a ‘substantial contributing 
factor’ to his injuries because he was required only to show that ‘he was, 
 
-39- 
 
more likely than not, exposed to lead paint at a given subject property.’  He 
argued that he was not required to prove only a single source of lead 
exposure or a single cause of his injuries.   
 
Id., 213 Md. App. at 601, 75 A.3d at 333.  The Circuit Court granted the defense motion 
for summary judgment, holding that the plaintiff “had not produced evidence sufficient to 
establish a prima facie case of lead exposure at the one property at issue here, and the 
court declined to allow [the plaintiff’s expert] to fill the causal gaps.”  Id., 213 Md. App. 
at 591-92, 75 A.3d at 328. 
On appeal, the Court of Special Appeals stated that “an expert cannot transform 
thin evidence or assumptions into viable causal connections simply by labeling them an 
expert opinion.”  Id., 213 Md. App. at 608, 75 A.3d at 338; see also Taylor v. Fishkind, 
207 Md. App. 121, 142, 51 A.3d 743, 756 (2012) (“‘[a]n expert’s opinion testimony must 
be based on [an] adequate factual basis so that it does not amount to conjecture, 
speculation, or incompetent evidence.’”) (quoting Giant Food, Inc. v. Booker, 152 Md. 
App. 166, 182-83, 831 A.2d 481 (2003) (alterations in original)).  Moreover, the court 
stated that Maryland courts “have for some time required more of a plaintiff than simply 
a showing that he lived in an old house in an area where lead-based paint historically was 
present.” Raymond Hamilton, 213 Md. App. at 612, 75 A.3d at 340; see also id. (“‘[T]he 
mere fact that most old houses in Baltimore have lead-based paint does not mean that a 
particular old Baltimore house has a similar deficiency.’”) (quoting Davis v. Goodman, 
 
-40- 
 
117 Md. App. 378, 393, 700 A.2d 798, 805 (1997)).21  Thus, the court emphasized that “a 
plaintiff bears the burden to establish the presence of lead in the child’s environment, and 
cannot just assume it merely from the age or location of the house.”  Id.  In applying 
those principles to the experts’ opinions in Raymond Hamilton, the Court of Special 
Appeals concluded that neither of the experts possessed the qualifications necessary, nor 
the factual basis, to render an opinion as to the source of the lead that the child ingested.  
Moreover, the court reasoned that, similar to Ross, because the expert “reached a 
conclusion as to the source notwithstanding the presence of other potential sources of 
lead, and as such her opinion ‘was as likely to confuse as to assist a jury.’”  Id. (quoting 
Ross, 430 Md. at 664, 63 A.3d at 10). 
The intermediate appellate court held that, without the experts’ testimonies, “the 
evidence proffered here would have allowed a jury at most to find a possibility that the 
circumstantially-established lead exposure at the Appleton Street property was a source 
of [the plaintiff’s] alleged injuries.  That is not enough: a plaintiff must establish . . .  a 
probability that a property exposed him or her to injury-causing lead paint.”  Id., 213 Md. 
 
 
 
 
 
 
 
21 These statements in Raymond Hamilton and Davis—that the presence of lead 
paint cannot be determined based on the general area of an “old” house—were in 
response to the argument that the presence of lead paint should be presumed in all houses 
built in Baltimore City during certain time periods, in light of reports that indicate a high 
percentage of similarly situated houses contained lead paint.  The court concluded aptly 
that the inference had an insufficient factual basis.  In contrast, the hypothetical we 
presented earlier in this opinion at 35-36 differs in the type of factual basis upon which 
the inferences rely. 
 
-41- 
 
App. at 605, 75 A.3d at 336 (citing Ross, 430 Md. at 664, 63 A.3d at 10) (emphasis in 
original). 
In sum, Dow does not define the only set of circumstantial facts that may satisfy a 
plaintiff’s burden to establish a prima facie negligence case for lead paint poisoning.  The 
pertinent question to be asked is whether the particular circumstantial evidence permits 
an inference or inferences of the desired ultimate fact or facts as a “reasonable likelihood 
or probability,” and not a mere “possibility.”  To the extent that the Court of Special 
Appeals’s opinions discussed in this opinion suggest that the only way to prove a prima 
facie negligence case circumstantially is to eliminate every other reasonable possibility as 
an alternative source, we do not agree with the exclusivity of such a conclusion.  With 
this understanding and these principles in mind, we shall apply them to the present cases. 
C. Analysis 
i. Hamilton 
There was no direct evidence adduced of lead-based paint in the interior of 754 
Bartlett Avenue.  Moreover, there was no evidence, as there was in Dow, that the children 
spent substantially all of their time in one house, the subject property, such that the 
Circuit Court could conclude that a fact-finder could be persuaded that there was a 
reasonable probability that the subject property contained lead-based paint.  The Court of 
Special Appeals, in an unreported opinion, emphasized that, in order to prove a prima 
facie case, “the evidence . . . would have had to provide the experts with enough 
information to rule out other possible sources of lead exposure to create the 
circumstantial evidence that the Hamiltons were exposed to lead at the Bartlett house.”  
 
-42- 
 
Hamilton, slip op. at 21.  The intermediate appellate court held that the evidence in the 
Hamiltons’ case did not do so: 
Here, the Hamiltons presented an Arc report regarding exterior surfaces, the 
mother’s statements that the boys put paint chips in their mouths at the 
Bartlett house, the elevated blood levels, and the age of the house.  This 
evidence suggests, but is not sufficient to create a genuine dispute as to 
whether the Bartlett address contained lead paint unless the Bartlett 
property was the only place where the Hamiltons could have been exposed 
to lead paint. . . . Dr. Blackwell-White and Dr. Simon conceded that . . . 
two [other visiting] properties could not be ruled out as potential sources 
because there was some information that suggested they contained lead, 
and Dr. Simon specifically stated that the time spent at those houses 
increased the possibility of lead exposure. 
 
Id. at 20-21.  In so holding, the court acknowledged that “more than one home can be a 
substantial contributing source of lead and therefore, more than one landowner could be 
liable for a child’s lead poisoning.”  Id. at 21.  The court went on, though, stating: 
However, the underlying assumption in that statement is that both houses 
had the potential to cause injury because they actually contained lead.  
Based on our case law, to even enter the realm of ‘substantial contributing 
source,’ a house has to be shown to have had lead-based paint - - almost 
invariably in the interior of the building.  Without direct evidence that 
the Bartlett house contained lead, the Hamiltons’ only option was to 
eliminate other sources of lead poisoning, not to establish that the only 
place responsible for the Hamiltons’ lead poisoning was the Bartlett 
house, but to show that the Bartlett house contained lead.  However, 
neither of Hamiltons’ experts could eliminate the other potential sources of 
lead.  In fact, they were provided with little information on those other 
potential sources.   
 
Id. at 21-22 (emphasis added). 
 
The Court of Special Appeals recognized aptly the multi-layered nature of the 
causation analysis in circumstantial evidence cases.  The court stated that the Hamiltons 
were not required “to establish that the only place responsible for the Hamiltons’ lead 
 
-43- 
 
poisoning was the Bartlett house, but [were required] to show that the Bartlett house 
contained lead.”  Id. at 21.  We depart from the reasoning of the intermediate appellate 
court, however, that, without direct evidence, “the Hamiltons’ only option was to 
eliminate other sources of lead poisoning.”  Id.  As we discussed above at 35-36 in our 
hypothetical of the block of row houses, there may be other ways that an injured plaintiff 
may establish that it was probable that the interior of a subject house contained lead.  
Accordingly, the sole concern should not be that the Hamiltons’ experts were provided 
with little information on other potential sources of lead exposure.  Rather, the concern 
should be that the Hamiltons’ experts reached the conclusion that the house contained 
lead-based paint on a presumption that houses built during a certain time period contain 
typically lead-based paint.  Such a factual basis is insufficient for an expert to reach the 
conclusion that the interior of a specific property contained lead-based paint during the 
relevant time period.  
ii. Alston 
In Alston, at the end of the motions hearing, the Circuit Court concluded that the 
defense motion for summary judgment should not be granted on the basis of uncertainty 
over where Plaintiffs lived, even though there was very little evidence and that which was 
adduced was “extremely sketchy in this case.”  Instead, the judge granted the defendant’s 
motion for summary judgment on the basis of a failure to offer sufficient proof of 
causation linking the plaintiff’s elevated blood lead levels and the specific conditions of 
the subject properties.  The Circuit Court’s reasoning is important to our (and its) analysis 
and, thus, we expound further. 
 
-44- 
 
The Circuit Court accepted that Plaintiffs showed that the subject properties had 
“deteriorating paint” and that, at least for purposes of the summary judgment motion, 
Plaintiffs “exhibited elevated blood lead levels at around the time that they say they were 
living in these properties.”  Moreover, the Circuit Court acknowledged correctly that 
generally Plaintiffs could prove a causal link “indirectly by circumstantial means.”  The 
Circuit Court concluded, however, that the plaintiffs failed to forge the first inferential 
link because: 
I think the essential logical ingredient that must be present in order for Dow 
or a theory like Dow to apply is that logically there must be a -- a very 
strong conclusion that the lead [poisoning] that the plaintiffs were 
experiencing had to come from this source because there is no other 
logical source that is available. 
 
 (Emphasis added.)  The Circuit Court stated on the record that “there may be a number 
of ways that could be done” and then provided several examples: 
I’ve suggested one of them would be if there were visitation properties, that 
there is some evidence that tends to exclude those.  There might be 
evidence that the paint wasn’t deteriorating in those.  There might be 
evidence that they were built after a period when lead paint was likely 
present. [sic]  There might be evidence that the visits were very short, were 
supervised closely and the children didn’t ingest paint.  There may be a 
number of bases that might be advanced by plaintiff. 
 
The problem, the Circuit Court stated, was that “you simply have two wide open possible 
properties at the same time, either of which could have been the source of the lead that is 
alleged.  And that is insufficient to establish the prima facie case that the plaintiff would 
have to show on negligence.”   
 
On appeal, the Alstons argue that this analysis was defective.  We disagree.  
Plaintiffs bear the initial burden of proving circumstantially a prima facie negligence 
 
-45- 
 
case.  Part of that burden is to advance a viable theory of causation.  In the Alstons’ case, 
they argued a Dow theory of causation, but, as the Circuit Court noted, the Alstons failed 
to produce the quantum or quality of evidence noted in Dow, namely, they failed to 
eliminate other reasonably probable identified sources of lead exposure.  Thus, the 
Circuit Court’s comparison of the Alstons’ case to Dow was appropriate and its ultimate 
conclusion that the Alstons’ failed to meet their initial burden was correct. 
 
 
JUDGMENTS OF THE COURT OF 
SPECIAL 
APPEALS 
AFFIRMED.  
COSTS TO BE PAID BY PETITIONERS 
IN THEIR RESPECTIVE APPEALS.