IN THE SUPREME COURT OF THE STATE OF DELAWARE

CATHERINE BAKER, §

§ No. 393, 2022

Plaintiff-Appellant, §

§ Certification of Question of Law 

§ from the United States Court of 

v. § Appeals for the Third Circuit 

§ Appeal Nos. 21-3360 & 22-1333

CRODA INC., f/k/a Croda, Inc. §

§ Court below:

Defendant-Appellee. § U.S. District Court, D. Del.

§ Civil Action No. 1:20-cv-01108

Submitted: June 14, 2023

Decided: August 24, 2023

Before SEITZ, Chief Justice; VALIHURA, TRAYNOR, LEGROW, and 

GRIFFITHS, Justices, constituting the Court en Banc.

Upon Certification of Question of Law from the United States Court of Appeals for 

the Third Circuit. CERTIFIED QUESTION ANSWERED. 

CHRISTINE M. MACKINTOSH, Esquire (argued), and KELLY L. TUCKER, 

Esquire, GRANT & EISENHOFER P.A., Wilmington, Delaware, for Appellant 

Catherine Baker. 

KENNETH J. NACHBAR, Esquire, and MIRANDA N. GILBERT, Esquire, 

MORRIS, NICHOLS, ARSHT & TUNNELL, LLP, Wilmington, Delaware, and 

DAVID S. COOPER, Esquire (argued), QUINN EMANUEL URQUHART & 

SULLIVAN, LLP, New York, New York, and MICHELLE SCHMIT, Esquire, 

QUINN EMANUEL URQUHART & SULLIVAN, LLP, Chicago, Illinois, for

Appellee Croda Inc.
2

GRIFFITHS, Justice:

This Court has received a request from our colleagues on the United States 

Court of Appeals for the Third Circuit to answer the following question:

Whether an increased risk of illness, without present manifestation of a 

physical harm, is a cognizable injury under Delaware law? Or put 

another way, does an increased risk of harm only constitute a 

cognizable injury once it manifests in a physical disease?

This question arises in connection with a toxic tort class action in the United 

States District Court for the District of Delaware that was appealed to the Third 

Circuit. Delaware resident Catherine Baker filed suit individually and on behalf of 

fellow residents who live near Atlas Point, a chemical plant that regularly uses and 

emits ethylene oxide, a dangerous chemical.

Our answer is that an increased risk of illness without present manifestation 

of a physical harm is not a cognizable injury under Delaware law. This opinion gives 

the reasons for our answer.

I.

The facts relevant to our decision are taken from the Third Circuit’s 

certification request (“Certification Request”).

1 Croda Inc. (“Croda”) owns and 

1

See Supr. Ct. R. 41(c)(iv); E.I. DuPont de Nemours & Co. v. Fla. Evergreen Foliage, 744 A.2d 

457, 458 (Del. 1999). We treat these facts as undisputed for the purposes of deciding these legal 

issues. See Duncan v. Theratx, Inc., 775 A.2d 1019, 1021 (Del. 2001). We also provide some

limited background from Baker’s complaint, see Appendix to Opening Br. at A10-A37, and the 

District Court’s November 23, 2021 opinion (the “District Court Opinion”, see Opening Br. at Ex. 

B), purely for context for the reader. To the extent we refer to the complaint, we recognize that the 

allegations therein are disputed. 
3

operates Atlas Point, a chemical plant in New Castle, Delaware.

2 One of the 

chemicals used at the plant—ethylene oxide—is a known carcinogen.3 Croda uses 

ethylene oxide in the production of surfactant and the creation of ethylene glycol.4 

The plant regularly releases ethylene oxide gasinto the air, which lingers at breathing 

level in the communities surrounding Atlas Point.

5

 To make matters worse, the plant 

experienced a significant leak in 2018 from which thousands of pounds of the 

dangerous chemical escaped into the environment. Catherine Baker (“Baker”) and 

putative class members live within a class zone defined by specific census tracts 

surrounding the chemical plant.

6

 The Environmental Protection Agency estimates 

that, because of their exposure to the chemical, Baker and the putative class members 

are up to four times more likely to develop cancer than the average American.7

On August 24, 2020, Baker filed a class action lawsuit against Croda in the 

District of Delaware, alleging that Croda’s use and emission of ethylene oxide is an 

ultrahazardous activity and that it was strictly liable for “any injuries proximately 

resulting therefrom.”8 Baker’s complaint also alleged that Croda was liable for 

2 Opening Br., Ex. C (Certification Request) at 3; Complaint ¶ 1. 

3

Id.; Complaint ¶¶ 2, 6.

4 Certification Request at 3-4.

5

Id. at 4. 

6

Id.

7

Id.

8 Complaint ¶¶ 73-80.
4

public and private nuisance, negligence, and willful and wanton conduct.9 

According to the complaint, 

[a]s a direct and proximate result of [Croda’s tortious conduct] 

and the exposure to EtO resulting therefrom, Plaintiff and the Class 

Members presently suffer, and will continue to suffer, a present 

increased risk of illness, disease or disease process, and the resulting 

present need to incur the cost of reasonably medically necessary 

diagnostic testing for the early detection of illness, disease or disease 

process. Plaintiff and Class Members therefore seek as damages the 

cost of a medical monitoring program for such detection.10

Croda moved to dismiss the complaint, and the District Court granted the 

motion on November 23, 2021,11 holding that “fearing an increased risk of disease” 

is not a “legal injury” in Delaware.12 It found that the class “cannot recover damages 

for the risks of diseases that they do not yet have. And because each tort requires an 

injury, none of Baker’s torts survive this flaw.”13 The District Court permitted Baker 

to amend the complaint to show that the class suffered physical injury.14 Baker did 

not do so, and subsequently appealed to the Third Circuit.

On October 21, 2022, the Third Circuit petitioned this Court to answer the 

above question. In its petition, the court surveyed caselaw from this Court rejecting 

claims based on fear of disease absent physical injury, but concluded that “[a]

9

Id. at ¶¶ 81-123.

10 Id. at ¶ 102.

11 Opening Br. at Ex. B. 

12 District Court Opinion at 2.

13 Id. at 6. 

14 Id.
5

substantive difference exists between an injury based on a fear of disease and an 

injury based on an increased risk of disease.”15 Acknowledging the far-reaching 

implications of a decision to recognize an increased risk of disease as a cognizable 

injury—which it considered “an unsettled issue . . . under Delaware law”16—the 

Third Circuit turned to us for clarification.

II.

Certified questions of law are reviewed de novo.

17

III.

We answer the certified question as follows: an increased risk of illness 

without physical harm is not a cognizable injury under Delaware law. Stated 

differently, an increased risk of harm only constitutes a cognizable injury once it 

manifests in a physical disease. It is axiomatic that all tort claims require an injury.18

Under Delaware law, an “injury in fact” is defined as “an invasion of a legally 

protected interest which is (a) concrete and particularized and (b) actual or imminent, 

not conjectural or hypothetical.”19 An increased risk of illness, without more, is not 

15 Certification Request at 6.

16 Id. at 3.

17 PHL Variable Insurance Co. v. Price Dawe 2006 Insurance Trust, 28 A.3d 1059, 1076 (Del. 

2011).

18 Restatement (Second) of Torts § 7 (1965).

19 Dover Hist. Soc. v. City of Dover Plan. Comm’n, 838 A.2d 1103, 1110 (Del. 2003) (quoting 

Society Hill Towers Owners’ Ass’n v. Rendell, 210 F.3rd 168, 175-76 (3d Cir. 2000)).
6

“actual or imminent,” and thus does not constitute an injury. Below, we review the 

established precedent and public policy concerns underpinning our answer. 

A.

In Metro-North Commuter Railroad Company v. Buckley,

20 a case involving a 

railroad worker who was exposed to asbestos but had not been afflicted by disease, 

the United States Supreme Court rejected a claim for medical monitoring under a 

federal statute. The court assumed, and the parties did not dispute, that “an exposed 

plaintiff can recover related reasonable medical monitoring damages if and when he 

develops symptoms.”21 The court then examined state law cases to determine 

whether negligent exposure to a toxic substance that would cause exposed persons 

to incur medical costs was, in itself, a sufficient basis for tort recovery under federal 

law.

22 It observed that the states authorizing recovery for medical monitoring in the 

absence of physical injury “do not endorse a full-blown, traditional tort law cause of 

action for lump-sum damages” but rather “have suggested, or imposed, special 

limitations on that remedy.”23 It also highlighted the serious public policy concerns 

that could follow if it adopted “a traditional, full-blown ordinary tort liability rule,”

observing that “tens of millions of individuals may have suffered exposure to 

20 Metro-N. Commuter R. Co. v. Buckley, 521 U.S. 424 (1997).

21 Id. at 439 (emphasis added). 

22 Id. at 440.

23 Id. at 440-41.
7

substances that might justify some form of substance-exposure-related medical 

monitoring.”24 This fact, “along with uncertainty as to the amount of liability, could 

threaten both a ‘flood’ of less important cases . . . and the systemic harms that can 

accompany ‘unlimited and unpredictable liability.’”25

Turning to Delaware caselaw, we first review Mergenthaler v. Asbestos 

Corporation of America,

26 a case involving claims by present or former asbestos 

workers and their spouses. There, the court addressed “[w]hether a claim for the 

expenses of medically required surveillance and related mental anguish of the 

plaintiffs’ wives fails to state a claim upon which relief can be granted where there 

is no present physical injury.”

27

 The court held that present physical disease was 

required to state a claim under Delaware law.

28

 The court found that an essential 

element of a mental anguish claim is physical injury and because “plaintiffs-spouses 

concede that they have suffered no physical injury due to wrongful asbestos 

exposure,” such “concession is dispositive.”

29

Similarly, in Brzoska v. Olson,

30 the court found that “damages for claims of 

emotional distress or mental anguish . . . are recoverable only if [an] underlying 

24 Id. at 442 (emphasis added). 

25 Id.

26 480 A.2d 647 (Del. 1984).

27 Id. at 649. 

28 Id. at 651. 

29 Id.

30 668 A.2d 1355 (Del. 1995).
8

injury is shown.”31 There, former patients of a dentist who had AIDS brought claims 

for mental anguish and the cost of medical testing or monitoring, even though the 

patients had not contracted the disease. 

Baker reads these cases as adopting an “actual exposure” test permitting 

plaintiffs to recover for claims based on fear of disease when accompanied by “actual 

exposure” to a disease-causing agent.32 But, in conceiving this test, Baker relies on 

the Brzoska court’s analysis of the plaintiffs’ battery action, which, as an intentional 

tort, did not require physical injury in the presence of “conduct [] viewed as 

outrageous.”33 As to the plaintiffs’negligence action, the court applied Mergenthaler 

and concurred with the Superior Court’s finding that the plaintiffs could not recover

in the absence of a physical injury:

Here, plaintiffs have alleged no injuries which stem from their exposure 

to HIV. Instead, plaintiff’s alleged “injuries” arise solely out of 

their fear that they have been exposed to HIV. In essence, they claim 

mental anguish damages for their “fear of AIDS.” As noted 

in Mergenthaler, however, damages for claims of emotional distress or 

mental anguish (which would include fear of contracting a disease) are 

recoverable only if the underlying physical injury is shown. In this 

case, plaintiffs have sustained no physical injury, and, therefore, they 

could not recover under a negligence theory.34

31 Id. at 1362. 

32 See Opening Br. at 18, 20.

33 Brzoska, 668 A.2d at 1362.

34 Id. 
9

In United States v. Anderson,

35 the District of Delaware certified questions to 

our court, asking whether a testicular cancer patient could recover, as an element of 

damages, for an increased risk of cancer recurrence related to his doctors’ failure to 

diagnose his condition where evidence showed that he probably would not suffer 

future cancer. Though the court declined to answer whether an increased risk of 

cancer constitutes an independent cause of action,36 it observed in dicta that the 

“requirement of a preceding physical injury prohibits plaintiffs from claiming that 

exposure to toxic substances, for instance, has created an increased risk of harm not 

yet manifested in a physical disease.”

37

Our holding that an increased risk of illness, without more, cannot be a 

cognizable injury under Delaware law comports with the established principle 

espoused in Mergenthaler, Brzoska, and Anderson that claims in tort require an 

actual or imminent injury. To hold otherwise would constitute a significant shift in 

our tort jurisprudence. Further, the District Court’s observation that “Delaware tort 

law presupposes that plaintiffs will bring suits after they suffer physical symptoms, 

not before” is apt.38 As it stands, the statute of limitations for toxic tort claims starts 

to run when a plaintiff begins to experience physical effects.

39 In addition, toxic tort 

35 669 A.2d 73 (Del. 1995).

36 Id. at 79. 

37 Id. at 77. 

38 District Court Opinion at 5. 

39 Brown v. E.I. duPont de Nemours & Co., Inc., 820 A.2d 362, 368 (Del. 2003); see also In re 

Asbestos Litig., 2017 WL 3600418, at *1 (Del. Super. Aug. 18, 2017). 
10

plaintiffs are permitted to bring separate claims for separate diseases caused by one 

exposure.40 Accordingly, a future risk of illness without any present injury does not 

constitute an injury-in-fact in tort under Delaware law. 

B.

We also briefly turn to public policy concerns surrounding this issue, which

likewise inform our answer to the Third Circuit’s question. Indeed, as the Third 

Circuit noted, “the decision to recognize an increased risk of disease as a cognizable 

injury is significant, and its implications are far reaching.”41 

Justice Breyer observed in Metro-North that “contacts, even extensive 

contacts, with serious carcinogens are common.”

42 Indeed, “tens of millions of 

individuals may have suffered exposure to substances” that may never result in any 

harm.43 Sadly, our reality 26 years later remains much the same, and courts have 

rightfully expressed concern that recognizing an increased risk of illness, without 

more, as a cognizable injury could open the floodgates to “endless and limitless” 

40 See Sheppard v. A.C. & S. Co., 498 A.2d 1126, 1134 (Del. Super. 1985), aff’d sub. nom. Keene 

Corp. v. Sheppard, 503 A.2d 192 (Del. 1986).

41 Certification Order at 6.

42 Metro-North, 521 U.S. at 434.

43 Id. at 442.
11

litigation.44 Dispensing with the physical injury requirement could also diminish 

resources that are presently used for those who have suffered physical injury.45

It is true, of course, that there are competing public policy concerns on this 

topic. As other courts have observed, medical surveillance damages promote early 

diagnosis and treatment of disease, and they can help to ameliorate the injustice of 

having economically disadvantaged persons pay for diagnostic testing.46 But, like 

the United States Supreme Court in Metro-North, “[w]e have not tried to balance 

these, or other, competing considerations here.”47 Rather, we highlight them to 

“explain why we consider the . . . cautions [in other decisions] to be important.”48 

In the future, if Delaware’s General Assembly decides to recognize medical 

monitoring as a separate cause of action, it is much better suited to address the 

complicated issues that would arise such as when the limitations period would begin 

to run, whether a higher pleading standard might be required, what type of test 

44 Rainer v. Union Carbide Corp., 402 F.3d 608, 621 (6th Cir. 2005) (internal quotations omitted); 

see also Caronia v. Philip Morris USA, Inc., 22 N.Y.3d 439, 451 (2013) (“dispensing with the 

physical injury requirement could permit tens of millions of potential plaintiffs to recover 

monitoring costs, effectively flooding the courts while concomitantly depleting the purported 

tortfeasor’s resources for those who have actually sustained damage); Henry v. Dow Chem. Co. 

701 N.W.2d 684, 694 (Mich. 2005) (“recognizing a cause of action based solely on exposure-one 

without a requirement of a present injury-would create a potentially limitless pool of plaintiffs”).

45 See Caronia, 22 N.Y.3d at 451.

46 See Redland Soccer Club, Inc. v. Dep’t of the Army & Dep’t of Def. of the U.S., 696 A.2d 137, 

145 (1997).

47 Metro-North, 521 U.S. at 434.

48 Id.
12

should be utilized to determine whether someone qualifies for medical monitoring,

49

or whether medical monitoring costs would be provided by a court-supervised 

fund,50 among others. But that is not within our purview today. 

For all the above reasons, we find that an increased risk of harm only 

constitutes a cognizable injury when manifested by physical illness. 

IV.

Having answered the certified question, we direct the Clerk to transmit this 

opinion to the Third Circuit.

49 The states that do allow medical monitoring for those with increased risk of disease without a 

present illness do not use utilize a standard framework to determine who is eligible for monitoring. 

Rather, numerous tests exist among state courts. See, e.g., Exxon Mobil Corp. v. Albright, 71 A.3d 

30, 80-81 (Md. App. 2013) (describing four-part test); Donovan v. Philip Morris USA, Inc., 455 

Mass. 215, 226 (2009) (describing seven-part test, including requirement of “subcellular” injury); 

Potter v. Firestone Tire & Rubber Co., 6 Cal. 4th 965, 1006 (1993) (describing five-part test).

50 See Metro-North, 521 U.S. at 441 (citing cases); see also, e.g., Exxon, 71 A.3d at 80-81 (same).