Cambridge Isotope Laboratories, Inc. v. United States

Slip Op. 26-
UNITED STATES
COURT OF INTERNATIONAL TRADE
Court No. 23-00080
CAMBRIDGE ISOTOPE LABORATORIES, INC.,
Plaintiff,
v.
UNITED STATES,
Defendant.
Before: M. Miller Baker, Judge
OPINION
[Remanding the Department of Commerce’s scope rul-
ing.]
Dated: March 11, 2026
George R. Tuttle, III, Law Offices of George R. Tuttle,
A.P.C., San Rafael, CA, on the briefs for Plaintiff.
Daniel Bertoni, Trial Attorney, Commercial Litigation
Branch, Civil Division, U.S. Department of Justice,
Washington, DC, on the brief for Defendant. Of coun-
sel for Defendant was Ruslan N. Klafehn, Attorney,
Office of the Chief Counsel for Trade Enforcement &
Compliance, U.S. Department of Commerce, Washing-
ton, DC.
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Baker, Judge: An importer challenges the Depart-
ment of Commerce’s determination that the company’s
product is within the scope of antidumping and coun-
tervailing 	duty 	orders 	covering 	ammonium 	sulfate
from China. The court remands because the agency’s
decision is contrary to law.
I
Because of the nature of the marketplace and the
“everchanging varieties of merchandise,” Saha Thai
Steel Pipe Pub. Co. v. United States, 101 F.4th 1310,
1315 (Fed. Cir. 2024), questions sometimes arise “as to
whether a particular product is subject to” an anti-
dumping or countervailing duty order. Congress has
accordingly 	authorized 	the 	Department 	to 	decide
“whether a particular type of merchandise is within
the class or kind of merchandise described in an exist-
ing . . . antidumping or countervailing duty order.”
19 U.S.C. § 1516a(a)(2)(B)(vi).
An implementing regulation establishes the rele-
vant procedures. See 19 C.F.R. § 351.225. 1 It allows an
“interested party” 	to ask 	Commerce 	to “determine
whether a product . . . is covered by the scope of an
order.” Id. § 351.225(c)(1). It also prescribes what in-
formation 	the 	applicant 	must 	provide. 	Id.
§ 351.225(c)(2). It then sets out “a multi-part regula-
tory framework” for the agency to follow in deciding
whether the product is in-scope. Vandewater Int’l, Inc.
1 Commerce amended § 351.225 in September 2023 and
March 2024, but those revisions are not relevant here.
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v. United States, 130 F.4th 981, 984 (Fed. Cir. 2025)
(citing 19 C.F.R. § 351.225 generally).
That framework directs the Department to “con-
sider 	the 	language 	of 	the 	scope.” 	19 	C.F.R.
§ 351.225(k)(1). Commerce “may make its determina-
tion on this basis alone if the language of the scope . . .
is dispositive.” Id. But in evaluating the scope lan-
guage, the agency also has “discretion” to consider cer-
tain “primary interpretive sources” and “secondary in-
terpretive 	sources.” 	Id. 	§ 	351.225(k)(1)(i), 	(ii). 	The
agency need not “first determine whether the scope
language is clear on its face before turning to” these
“(k)(1)” sources. Magnum Magnetics Corp. v. United
States, — F.4th —, 2026 WL 438170, at *4 (Fed. Cir.
Feb. 17, 2026). 2
The primary sources are descriptions of the mer-
chandise in the original petition that led to the duty
order, descriptions of the goods in the initial investiga-
tion resulting in the order, previous or concurrent
2 Earlier Federal Circuit case law described the step of an-
alyzing whether the order’s language is unambiguous “as
the ‘(k)(0)’ inquiry because it precedes the analyses under
sections (k)(1) and (k)(2) of [the] regulation.” Vandewater,
130 F.4th at 984–85 (citing Meridian Prods. LLC v. United
States, 851 F.3d 1375, 1381 (Fed. Cir. 2017)). Magnum
Magnetics, however, explains that those cases interpreted
a pre-2021 version of § 351.225 and “do not control Com-
merce’s consideration of the (k)(1) factors” under the cur-
rent regulation. — F.4th —, 2026 WL 438170, at *5. The
court held that the Department “has the discretion to con-
sider (k)(1) [sources] in assessing the meaning of the scope
language, regardless of whether the language appears to
be ambiguous or not.” Id. at *6.
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Commerce 	decisions 	(including 	scope 	rulings 	and
other orders with the same or similar language), and
International Trade Commission determinations “per-
taining 	to 	the 	order 	at 	issue.” 	19 	C.F.R.
§ 351.225(k)(1)(i).
The secondary sources are Commerce or Commis-
sion determinations not listed in (k)(1)(i), Customs rul-
ings or determinations, industry usage, dictionaries,
“and 	any 	other 	relevant 	evidence.” 	Id.
§ 351.225(k)(1)(ii). In the event of any conflict, the pri-
mary sources “will normally govern in determining
whether a product is covered by the scope of the order
at issue.” Id.
If the plain language and the (k)(1) sources do not
resolve 	the 	matter, 	Commerce 	may 	consider 	five
“(k)(2) factors”—the product’s physical characteristics,
the ultimate users’ expectations, the product’s ulti-
mate use, the channels of trade in which it is sold, and
the manner in which it is advertised and displayed.
19 C.F.R. § 351.225(k)(2)(i)(A)–(E). “The (k)(2) criteria
help to determine whether a product is sufficiently
similar 	as 	merchandise 	unambiguously 	within 	the
scope of an order as to conclude the two are merchan-
dise of the same class or kind.” Vandewater, 130 F.4th
at 985 (cleaned up). Paragraph (k)(2)(ii) adds that if
the (k)(2) factors conflict, the product’s physical char-
acteristics (the (k)(2)(i)(A) criterion) “will normally be
allotted 	greater 	weight 	than 	the 	other 	factors.”
19 C.F.R. § 351.225(k)(2)(ii).
The two parts of the regulation differ in a critical
respect. In setting out the primary and secondary
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interpretive sources, paragraph (k)(1) gives the De-
partment discretion to consider the ones it deems ap-
propriate—it need not consider all of them. See id.
§ 351.221(k)(1)(i) (“The following primary interpretive
sources may be taken into account . . . at the discretion
of 	the 	[agency.]”) 	(emphasis 	added); 	id.
§ 351.221(k)(1)(ii) (“[Commerce] may also consider sec-
ondary interpretive sources . . . , such as [non-exclusive
list follows].”) (emphasis added). But paragraph (k)(2)
offers no such flexibility. Its language is mandatory:
“If the [Department] determines that the sources un-
der paragraph (k)(1) of this section are not dispositive,
[it] will then further consider the following factors[.]”
Id. § 351.225(k)(2)(i) (emphasis added).
II
In 2017, Commerce issued antidumping and coun-
tervailing 	duty 	orders 	covering 	ammonium 	sulfate
from China. See 82 Fed. Reg. 8403; 82 Fed. Reg. 4850.
They apply to
ammonium sulfate in all physical forms, with or
without additives such as anti-caking agents.
Ammonium sulfate . . . has the chemical formula
(NH 4 ) 2 SO4 .
. . . .
The Chemical Abstracts Service (“CAS”) registry
number for ammonium sulfate is 7783–20–2.
. . . . Although this . . . CAS registry number [is]
provided for convenience and customs purposes,
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the written description of the scope of the orders
is dispositive.
Appx1150–1151.
Cambridge Isotope Laboratories imports “enriched
15 N 	ammonium 	sulfate 	isotope” 	from 	China.
Appx1001. In 2022, the company requested that Com-
merce opine that this compound is outside the orders’
scope. Id.
Cambridge explained that the isotope’s formula is
(15 NH 4 )2 SO4 , while “naturally abundant” ammonium
sulfate has the formula (NH4 ) 2 SO4 . Appx1007. The lat-
ter formula is referred to in the duty orders; the former
is not—at least, not explicitly, a matter discussed fur-
ther below. See Appx1150. The importer stated that
the difference between the two substances is that its
blend is “enriched with a 15 N nitrogen atom, making it
physically a different product with a different molecu-
lar weight.” Appx1012. The company also emphasized
that the enriched version has a CAS registry number
of 43086–58–4, unlike the standard sulfate’s 7783–20–
2, which it said “reflects the difference between it and
[a]mmonium 	sulfate 	with 	a 	chemical 	formula 	of
(NH4 ) 2 SO4 .” Id. It said the enriched sulfate’s primary
use is for laboratory research and contrasted that to
the standard compound’s use as a commercial mineral
or chemical fertilizer. Appx1007–1008.
In contending that its enriched product is out-of-
scope, Cambridge pointed to the chemical formula, the
product’s physical characteristics, user expectations,
ultimate use of the product, channels of trade, and the
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manner of advertising and display. Appx1009–1010.
Although it did not cite the regulation as part of that
discussion, the paragraph headings plainly reflected
the (k)(2) factors with only minor wording differences.
Compare 	id. 	(headings) 	with 	19 	C.F.R.
§ 351.225(k)(2)(i)(A)–(E).
Commerce found the enriched ammonium sulfate
in-scope and purported to do so based on the duty or-
ders’ language, which it observed “plainly states that
the Orders cover ‘ammonium sulfate in all physical
forms.’୻” Appx1318 (quoting Appx1150). Cambridge, in
turn, did “not argue that its enriched 15 N ammonium
sulfate is not ammonium sulfate.” Id. Rather, the com-
pany stated that “its product is ammonium sulfate, but
enriched with a nitrogen atom,” and explained that the
standard compound naturally contains 15N and the en-
riched form simply has more of it. Id. The agency thus
concluded that (NH 4 ) 2 SO4 already contains 15 N. Id. Be-
cause the only difference is that Cambridge’s enriched
product contains a higher concentration, it “is still am-
monium sulfate, and the scope of the Orders includes
‘ammonium sulfate in all physical forms.’୻” Id.
The agency brushed aside the company’s argument
about the different CAS registry numbers because “the
written description of the scope of the Orders is dispos-
itive.” Id. (quoting Appx1151). It also found it unnec-
essary to consider Cambridge’s arguments about how
the enriched product is used—one of the (k)(2) factors.
This was because (in its view) it resolved the matter
based on the orders’ plain language, as illuminated by
“the description of the product contained in the scope
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ruling request,” 	id.—a (k)(1) source, 	see 19 C.F.R.
§ 351.225(k)(1)(i)(A).
III
Invoking 	jurisdiction 	conferred 	by 	28 	U.S.C.
§ 	1581(c), 	Cambridge 	sued 	under 	19 	U.S.C.
§ 1516a(a)(2)(B)(vi) to challenge the scope ruling. The
parties have fully briefed Cambridge’s motion for judg-
ment on the agency record, which is ripe for decision.
The court “will uphold Commerce’s scope determi-
nations unless they are unsupported by substantial
evidence or otherwise not in accordance with law.”
Magnum Magnetics, — F.4th —, 2026 WL 438170,
at *3 (citing 19 U.S.C. § 1516a(b)(1)(B)(i)). “Substan-
tial evidence means ‘such relevant evidence as a rea-
sonable mind might accept as adequate to support a
conclusion.’୻” Id. (quoting Consol. Edison Co. v. NLRB,
305 U.S. 197, 217 (1938)).
IV
Cambridge attacks Commerce’s decision on multi-
ple grounds, but the court need only consider one. 3 The
importer contends that the evidence it presented to the
agency shows that “trade and industry do not consider
15N isotopically enriched ammonium sulfate used for
3 The government also moves to strike a Customs classifi-
cation ruling attached to Cambridge’s reply brief that is not
part of the administrative record. See ECF 41, at 1. The
court denies the motion as unnecessary to decide because
remand is required without regard to the importer’s argu-
ments based on the attachment.
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laboratory research to be ammonium sulfate, which is
used as fertilizer.” ECF 37-2, at 19 (emphasis in origi-
nal). “Despite their similarities in name,” these two
compounds “are different in their chemical composi-
tion.” Id. The Department failed to consider this argu-
ment because it purported to rely on the “plain lan-
guage of the scope of the Orders” and “the description
of the product contained in the scope ruling request,”
Appx1318—the latter being a (k)(1)(i) source.
The court reviews agency action based on its sub-
stance, not its form or label. See, e.g., Mattel, Inc. v.
United States, 377 F. Supp. 955, 963 (Cust. Ct. 1974)
(Maletz, J.) (treating matter as a 19 U.S.C. § 1514 pro-
test when Customs’s ruling said the agency was re-
viewing it under 19 U.S.C. § 1520(c) but actually ap-
plied the factors relevant under § 1514); Ctr. for Envt’l
Health v. Ragan, 103 F.4th 1027, 1034 (4th Cir. 2024)
(stating that court does “not accept as definitive” an
agency’s “characterization of its decision” and that in-
stead court looks to “the contents” of the action) (em-
phasis in original) (citing Azar v. Allina Health Servs.,
587 U.S. 566, 575 (2019)).
Labels aside, Commerce grounded its decision on
the chemical composition of Cambridge’s product. The
agency found that because both ammonium sulfate
and the importer’s enriched sulfate contain 15 N, the
latter is in-scope. Appx1318. “Therefore, based on rec-
ord evidence, by definition enriched 15 N ammonium
sulfate is still ammonium sulfate, and the scope of the
Orders includes ‘ammonium sulfate in all physical
forms.’୻” Id.
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The problem is that the “physical characteristics
(including chemical . . . characteristics) of the [im-
porter’s] 	product” 	is 	a 	(k)(2) 	factor. 	See 	19 	C.F.R.
§ 351.225(k)(2)(i)(A). 4 But the Department expressly
declined 	to 	consider Cambridge’s arguments 	about
other (k)(2) factors. See Appx1318 (“Commerce finds it
unnecessary to consider the arguments [the company]
raises regarding the end uses of enriched 15 N ammo-
nium sulfate.”).
That was contrary to law because the regulation
does not permit the agency to pick and choose which of
the (k)(2) factors it considers—they’re one for all and
all for one. See 19 C.F.R. § 351.225(k)(2)(i) (“[T]he [De-
partment] will then further consider the following fac-
tors[.]”) (emphasis added). And the regulation requires
weighing those five criteria and provides that, in the
event of a conflict between them, the “physical charac-
teristics” “will normally be allotted greater weight”
4 The court acknowledges that Commerce stated that it re-
lied on “the description of the product contained in the
scope 	ruling 	request”—a 	(k)(1) 	source, 	see 	19 	U.S.C.
§ 351.225(k)(1)(i)(A)—to illuminate the orders’ scope lan-
guage. Appx1318. But to read that general provision as in-
cluding the “physical characteristics (including chemical
. . . characteristics) of the [importer’s] product” would ne-
gate the more specific § 351.225(k)(2)(i)(A). Under the gen-
eral/specific canon, the latter clause must prevail over the
former. That’s because “the specific provision comes closer
to addressing the very problem posed by the case at hand
and is thus more deserving of credence.” Scalia and Garner,
Reading Law: The Interpretation of Legal Texts 183 (2012).
But only § 351.225(k)(1)(i)(A)’s “application to cases cov-
ered by” § 351.225(k)(2)(i)(A) “is suspended; it continues to
govern all other cases.” Id. at 184.
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than the others. Id. § 351.225(k)(2)(ii). Because Com-
merce neither considered the other four (k)(2) fac-
tors—despite addressing one, and despite Cambridge
having discussed them in its scope ruling application,
see Appx1010—nor balanced them against each other,
the court must send this matter back to the agency’s
drawing board. If the Department looks to the (k)(2)
factors on remand, it must consider all of them.
* 	* 	*
The court remands for further proceedings con-
sistent with this opinion.
Dated: 	March 11, 2026 	/s/ M. Miller Baker
New York, NY 	Judge
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