Opinion for the Court filed by Circuit Judge STARR.
STARR, Circuit Judge:
This case is before us a second time. The Railway Labor Executives’ Association, a voluntary association which represents organized rail employees in the United States and Canada, once again raises issues pertaining to the impact of two federal statutes on Canadian employees of U.S. railroads operating in Canada. The Railroad Retirement Board (Board) determined that the Railroad Retirement Act of 1974 (RRA), 45 U.S.C. §§ 231-231u (1982 & Supp. Ill 1985), and the Railroad Unemployment Insurance Act (RUIA), 45 U.S.C. §§ 351-367 (1982 & Supp. Ill 1985), ceased to cover such employees as of April 10, 1978.
On that date, certain Canadian immigration regulations went into effect which, the Board concluded, had the impact of requiring the termination of retirement and unemployment benefits provided for under U.S. law and theretofore enjoyed by Canadian employees. The Association seeks review of the Board’s decision.
In our prior visitation to this case, we vacated the Board’s decision,
Railway Labor Executives’ Ass’n v. United States R.R. Retirement Bd.,
749 F.2d 856 (D.C.Cir.1984)
(RLEA I),
and remanded for further consideration of the federal and Canadian law issues. Subsequently, the Board issued the decision at issue in this case, adhering to its initial interpretation. The Association now challenges (1) the Board’s interpretation of federal and Canadian law, (2) its extension of that interpretation to elected union officials, and (3) its delay in reaching its decision, as having a prejudicial effect on Canadian workers. With one exception, we uphold the Board’s decision.
I
The RRA and RUIA provide a system of retirement and unemployment benefits for railroad workers. Administered by the Board, the system is funded through an employment tax levied under the Railroad Retirement Tax Act (RRTA), 26 U.S.C. §§ 3201-3233 (1982 & Supp. Ill 1985), and collected by the Internal Revenue Service.
The three federal statutes bearing on our case contain substantially similar definitions of the terms, “employer” and “employee.” The statutes generally cover service whether performed inside or outside the United States,
see
45 U.S.C. §§ 231(d)(1), 351(e), 26 U.S.C. § 3231(d).
All three measures, however, contain an exception, the interpretation of which is at the center of this case. The exception provides:
[A]n individual not a citizen or resident of the United States shall not be deemed to be in the service of an employer when rendering service outside the United States to an employer who is
required
under the laws applicable in the place wheré the service is rendered to employ therein,
in whole or in part,
citizens or residents thereof.
45 U.S.C. §§ 231(d)(3), 351(e), 26 U.S.C. § 3231(d)(7) (emphasis added).
In response to a request by Conrail, the IRS in January 1983 issued a Private Letter Ruling concluding that, as a result of recent amendments to Canada’s immigration laws, the RRTA-mandated exception applied to service rendered in our neighbor to the north.
See
R. at 13-17. In IRS’s view, the Canadian Immigration Act, 1976 2d Sess., ch. 52, § 10, and the 1978 regulations promulgated thereunder, constituted a law
requiring
the employment of Canadi
an citizens or permanent residents
in whole or in part
for railroad operations in Canada.
Pursuant to normal inter-agency coordination procedures (and prior to issuing its ruling), the IRS notified the Railroad Retirement Board’s General Counsel that it was considering Conrail’s request. At that juncture, the General Counsel initiated a review of the status of Conrail’s Canadian employees under the RRA and RUIA. To do so, an examination of Canadian law similar to the one the IRS had undertaken was of course required.
The Canadian Immigration Act provides in pertinent part that, prior to appearing at a port of entry, any non-citizen or nonresident of Canada seeking to enter that country for purposes of engaging in employment must obtain an employment authorization. Immigration Act, 1976 2d Sess., ch. 52, § 10. Canada’s Minister of Employment and Immigration duly promulgated regulations establishing guidelines for the issuance of employment authorizations.
See
112 Can.Gaz., Part II, No. 5, §§ 18-20 (March 8, 1978).
In their review, the Board’s General Counsel and Deputy General Counsel concluded that the Immigration Act and its implementing regulations (primarily section 20) required American employers in Canada to hire Canadian citizens in whole or in part, and therefore triggered the service exceptions.
Their view thus mirrored that of IRS as embodied in its Conrail Private Letter Ruling. On January 10, 1984, the
Board affirmed the General Counsel’s interpretation without discussion.
RLEA appealed from the Board’s decision, arguing that the latter’s interpretation of
Canadian
law was not entitled to deference and was therefore subject to
de novo
review.
RLEA I,
749 F.2d at 859, 860. We agreed,
but concluded that the issue required a determination “whether the relevant provisions of foreign law come within the meaning of sections 231(d)(3) and 351(e) [of the RRA and RULA].”
RLEA I,
749 F.2d at 860. Standards were therefore needed in order to evaluate what brought a foreign law within the service exception. We observed that under the two statutes Congress implicitly delegated to the Board the task of elaborating the necessary standards. Inasmuch as the language of the statute itself did not compel the adoption of a particular meaning (and since the legislative history was inconclusive), we stated that we would be obliged under settled principles to defer to the Board’s interpretation, if reasonable, of its governing statute.
RLEA I,
749 F.2d at 860 (citing
Chevron U.S.A., Inc. v. Natural Resources Defense Council,
467 U.S. 837, 104 S.Ct. 2778, 81 L.Ed.2d 694 (1984)).
We concluded, however, that the Board had failed in three respects to set forth a reasonable basis for its interpretation. The Board (1) failed to provide a general definition of what types of foreign legal provisions constitute laws satisfying the requirement language of the exception; (2) failed to provide a reasoned analysis of why Canadian law satisfied that language; and (3) acted upon a record that was inadequate to support its interpretation of Canadian law.
See RLEA I,
749 F.2d at 862-64.
II
Following
RLEA I,
the Board reconsidered its decision and in May 1986 issued the decision now before us.
The Board, in effect, stood its ground. After elucidating what it viewed as the governing standards, the Board stated that foreign service is excluded from statutory coverage if the foreign legal provisions (1) expressly mandate that all, or a stipulated percentage or number, of employees be local citizens or residents; (2) mandate that certain occupations, skills, or types of work found in the railroad industry be performed by locals; (3) create a preference for the hiring of locals that imposes such stringent barriers to employment of non-locals that the measures “in effect” require the employer to hire locals; or (4) are
in practice
administered in such a way as to “in effect” require the hiring of locals, regardless of whether they require on their face that locals be hired. To determine whether a foreign law creates a preference or a requirement, the Board stated that it will examine both the wording of the provisions in question and the intention of the foreign government in enacting them. R. at xv-xvi.
Applying this interpretation to the pertinent Canadian provisions, the Board concluded that, both on their face and as applied, the regulations implementing the Immigration Act “in effect” require the hiring of locals.
Id.
at xix, xxiv-xxv. The Board based this conclusion on its determination that for an employer to obtain a Canadian employment authorization for a non-local, it “must not only show that [it] made every effort to hire or train a Canadian for the job but also must set up programs so that in the future there will be no need to look for foreigners for employment needs.”
Id.
at xxiv. The Board stated that the Canadian regulations not only make it very difficult to hire non-locals, but are “applied in such a way as to make it impossible, eventually, to hire an alien for many, if not all, positions.”
Id.
at xxv.
In addition, because unions (as employers) are subject to the Immigration Act and its regulations, the Board concluded that services performed in Canada by (non-local) railroad union representatives are likewise subject to the exception. The Board stated that even if the Immigration Act and its regulations do not apply to
elected
union officials, there is no exception for union support staff. In the Board’s view, since a union-employer’s hiring practices would in general be subject to the Canadian regulatory regime, the implementing regulations would require the union to employ Canadian locals at least “in part.”
Id.
at xxxi. The Board saw no reason to treat elected union officials and union support staff differently.
RLEA challenges the Board’s decision on three grounds. It contends that (1) the Board incorrectly interpreted Canadian law as triggering the service exception; (2) even if the Board’s construction of the service exception is correct, its extension of the ruling to elected union officials is unreasonable; and (3) the Board delayed unreasonably in reaching a decision, and that to avoid prejudice to Canadian employees, its decision (even if valid) should apply prospectively only.
A.
Interpretation of the Service Exception in the RRA and RUIA.
RLEA contends that the service exception was meant to apply only to special — indeed unique — situations that obtained in Mexico and Cuba in the 1930s and 1940s.
Moreover, even if the exception were not intended to be so delimited, it was nonetheless meant to be applied only in situations in which foreign law barred the deduction of railroad retirement taxes from the salaries of employees, or otherwise presented formidable administrative impediments to implementation and administration of the RRA and RUIA. RLEA further argues that the decision fails to provide a coherent standard by which foreign legal provisions may be measured.
As we indicated in
RLEA I,
the Board’s interpretation of its own organic statutes is reviewed under the now familiar standards articulated in
Chevron
and its progeny.
See NLRB v. United Food & Commercial Workers Union,
— U.S. —, 108 S.Ct.
413, 98 L.Ed.2d 429 (1987);
INS v. Cardoza-Fonseca,
— U.S. —, 107 S.Ct. 1207, 94 L.Ed.2d 434 (1987);
Chevron,
467 U.S. 837, 842-43, 104 S.Ct. 2778, 2781-82 (1984). These principles, recently clarified in
United Food Workers,
can be set forth concisely: “[0]n a pure question of statutory construction, our job is to try to determine congressional intent, using ‘traditional tools of statutory construction.’ ” 108 S.Ct. at 421 (citation omitted). If, however, “ ‘the statute is silent or ambiguous with respect to the specific issue, the question for the court is whether the agency’s answer is based on a permissible construction of the statute.’ ” 108 S.Ct. at 421 (quoting
Chevron,
467 U.S. at 843, 104 S.Ct. at 2782).
In
RLEA I,
we indicated that neither the words of the exception nor its legislative history “gives us any clue as to the meaning Congress intended,” 749 F.2d at 861; we reached this conclusion after canvassing the pertinent House and Senate Reports.
Now, however, both RLEA and the Board argue that a fresh examination of the legislative history antedating enactment of the service exception (and not presented to us in
RLEA I)
supports their respective interpretations.
This “fresh” history is, in the main, made up of correspondence dating from 1938 between the General Counsel of the Pullman Company and the Chairman of the Railroad Retirement Board. This golden-anniversary correspondence concerned how best to handle problems that had arisen in administering the two statutes in countries such as Mexico; however, each proposal either raised new problems or failed adequately to address relevant concerns. The Board therefore opted for a
general
service exception, which was ultimately enacted and became the provision at issue in this case.
The Board argues that these documents, together with language in other pertinent portions of the legislative history, make it clear that Congress deliberately chose general, rather than country-specific language.
See
Brief for Respondent at 11-12; R. at x-xiii.
The Association nonetheless, contends that the legislative history shows that Congress intended to address only a very narrow, country-specific problem. In the Association’s view, Congress was concerned solely with the “logistical and administrative problems of administering a retirement and unemployment benefits program,” Brief for Petitioner at 17, in countries (such as Mexico and Cuba) whose law impeded the funding of benefits programs both by requiring railroads to employ citizens or residents of that country, and by prohibiting the employer from deducting railroad retirement taxes from foreign employees’ compensation.
See id.
at 16-25.
As we see it, both sides have somewhat missed the mark in this regard. The newly presented materials help to clarify the nature of the underlying problem, but the materials fail to provide us with a clear expression of Congress’ intent on the critical interpretive issue — the breadth of applicability of the covered service exception. The will of Congress in this particular remains clouded. Plainly, the general language of the exception forecloses the Association’s preferred reading, but the question remains as to the provision’s scope at its outer perimeter. Accordingly, we will defer to the Board’s interpretation if it is reasonable. We believe it is, for reasons now to be set forth.
This, we observe preliminarily, should come as no surprise. In
RLEA I,
we specifically stated that the service exception was amenable to varying interpretations.
See RLEA I,
749 F.2d at 861. Our concern with the Board’s previous decision was that it failed to articulate which interpretation it was adopting. To be sure, the underlying Legal Opinions reached the conclusion that Canadian law requires employers in Canada to hire Canadians, but those opinions failed to provide a definition of the terms “required” and “in whole or in part.” Nor did the opinions articulate a standard against which foreign law would be measured.
In contrast, the decision now before us expressly sets forth the Board’s understanding of the pivotal terms “required” and “in whole or in part.” It also explains how the Board will analyze foreign laws. Indeed, the Board has crafted a definition of the exception that includes the interpretations we previously suggested were possible. Indicia of reasonableness under
Chevron
therefore abound.
The Association is, of course, of an entirely different view. It asserts that, even if the Board’s interpretation is not overly broad, it is unreasonably muddled. The Association argues primarily that the Board incorrectly concluded that
preferences
placing U.S. citizens on an unequal footing with the foreign country’s citizens or residents constitute
requirements.
Not so. The Board’s decision clearly stated that a foreign law that does not place U.S. citizens and the foreign country’s citizens or residents on an equal footing will be treated as a
preference
for hiring foreign locals,
unless
the preference is written or administered so that it “in effect” requires the hiring of the country’s citizens or residents in whole or in part. This explanation, we are satisfied, discharged the Board’s obligation to adduce a reasonable interpretation.
B.
Application of the Service Exceptions to Canadian Law.
As we indicated in
RLEA I,
an agency is not entitled to
Chevron
-style deference when it interprets statutes outside its own area of expertise; accordingly, we concluded that our review of the Board’s determination of
Canadian law
is
de novo. RLEA I,
749 F.2d at 860. We observed that we found it “difficult to see how a reasonable assessment of Canadian law could be made on the basis of the evidence entered in the record.”
RLEA I,
749 F.2d at 863. Based upon the scanty record before us at that time, it appeared that (save for the Immigration Act and its regulations) the only evidence considered by the Board was Conrail’s presentation in its request for an IRS Private Letter Ruling, and a letter from a Canadian lawyer submitted by the Association.
It appears in contrast that on its second review of the issue the Board considered a much wider range of evidence. The current decision indicates that the Board considered a healthy array of interpretive guides, which we note in the margin.
To support their position as to the meaning of Canadian law, both RLEA and the Government of Canada emphasize that U.S. railroads operating in Canada have succeeded in hiring large numbers of Americans over the past several years. With all respect, however, this argument fails to address the core question raised by the
service exceptions — whether Canadian law in effect requires U.S. railroads to hire
even in part,
for
any
position, Canadian citizens and residents. Neither RLEA nor the Canadian Government, as
amicus,
has come forward with evidence that Canadian law does in fact erect such a requirement.
In that respect, the Government of Canada argues that the Board improperly declined to give any weight to Canada’s administrative waiver of the application of Regulation 20(l)(a) for all U.S. railway workers from November, 1979 until June, 1981. Brief for Amicus Curiae at 16-19. The Board, however, specifically addressed the effect of this waiver on its interpretation; the Board indicated that, although the immigration regulations were administratively waived for 19 months with respect to railroad workers, service coverage under the two statutes was not to be an “on again, off again” proposition based upon administrative or operational changes in a country’s immigration policy. R. at xxvi. Instead, once the Board determines that a country’s
laws
satisfy the service exception’s requirement, the Board will decline to examine the laws’
operation
to determine whether in practice those laws operate with the restrictive sweep facially indicated.
In our view, this is an entirely sensible approach, by virtue of the values of certainty and predictability fostered by the Board’s interpretive method (not to mention the obvious difficulties in administration spawned by a contrary approach). But even so, the Board left the door partially ajar; under its approach, an exception might arise if the waiver represented a clear statement of permanent government policy or of a reciprocal employment agreement applicable to railroad employees generally, as opposed to an ad hoc waiver (of limited duration).
Neither the Association nor the Government of Canada has persuasively rebutted either the Board’s determination of the ef-feet of Canadian law or the validity of the interpretive guides upon which the Board relied. The record is sufficient, we believe, to enable us to make a reasoned determination of Canadian law. And in so doing, we find ourselves in accord with the Board essentially for the reasons stated by it. We thus agree that Canadian law creates a preference for the hiring of Canadians which, both facially and as applied, imposes barriers to the employment of non-Canadians so stringent that they “in effect” require an employer to hire Canadians.
C.
Application of the Board’s Decision to Elected Union Representatives.
As we noted above,
see supra
p. 468, both the RRA and the RUIA cover service rendered to any U.S. railway labor organization, whether it is performed within or without the United States. Both statutes therefore cover service performed by elected union officials within Canada. Without addressing the question in detail, the Board in the course of its decision determined that the service exceptions apply to elected union officials. The reason was that unions — just as all other employers operating in Canada — are in effect required, at least in part, to hire Canadians for
other
positions. The Board stated, in essence, that if
some
of an employer’s employees come within the exception, then
all
do.
The Association challenges the Board’s determination as unreasonable, and the application of the service exception to elected union officials as improper. Brief for Petitioner at 37-39. The Association asserts that Canadian law does not control in any respect the citizenship or residency of elected union officials and that there is no record evidence that any U.S. labor organization active in Canada actually employs support staff in Canada.
We agree with the Board that, even if Canadian immigration law is inapplicable to
elected union officials, a union that in fact hires employees (other than elected officials) would come within the exception. If, on the other hand, the Association is correct that union employers do not as a matter of course employ in Canada persons other than elected union officials, a genuine question exists concerning the lawfulness of applying the service exception to elected union officials, inasmuch as they may be a particular union’s only employees in Canada. This issue, we are persuaded, depends on several factual matters not in the record before us. Moreover, the parties have neglected to focus on the legal questions that could arise depending on what the facts are. For these reasons, we therefore decline once again to pass on the correctness of the Board’s application of the exception to elected union officials, vacate the Board’s ruling with respect to the issue, and remand for reconsideration by the Board.
Ill
The final issue before is the Association’s complaint that the eighteen-month period between this court’s decision in
RLEA I
in December 1984 and the Board’s decision in May 1986 constituted unreasonable delay, which prejudiced affected Canadian employees. Accordingly, the Association requests that (assuming the Board’s decision is upheld) we limit the effective date of its ruling to May 6, 1986 (the date of the Board’s decision). The Board replies that the eighteen-month period was not unreasonably long in light of the importance and difficulty of the issues, and that the delay was necessary to coordinate implementation of the RRA and RUIA with implementation of the RRTA by IRS. The Board also argues that its actions did not prejudice the rights of any Canadian employees.
The Association urges us to review its claim of unreasonable delay in light of the factors set forth in
Telecommunications Research Action Center v. FCC,
750 F.2d 70 (D.C.Cir.1984)
(TRAC).
In
TRAC,
however, the issue was whether this court had jurisdiction (and, if so, exclusive jurisdiction) to compel FCC action unreasonably delayed, questions we resolved in the affirmative. In the course of that decision we set forth guidelines for evaluating the appropriateness of compelling agency action alleged to be unreasonably tardy.
See TRAC,
750 F.2d at 79-80.
Here, of course, the Association does not seek to compel agency action unreasonably withheld; rather, it is seeking to modify final action already taken by the Board on the ground that the agency unreasonably delayed in reaching its decision. For this reason,
TRAC
is not directly apposite. We do, however, review petitioner’s claim of unreasonable delay to determine whether the eighteen-month period was “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.” 5 U.S.C. § 706(2)(A) (1982).
Cf. TRAC,
750 F.2d at 76 n. 29.
We are persuaded that the claim of unreasonable delay is ill-founded. The Association has failed to show that any Canadian employees were prejudiced by the Board’s delay (even assuming it to be unreasonable). The Association claims that the Board’s delay adversely affected some 2000 employees and pensioners, whose service during the years 1983-1985 was effectively treated as if subject to the service exception, even after this Court’s decision in
RLEA I.
Brief for Petitioner at 40.
But our holding today establishes that those employees and pensioners have obviously
not
been adversely affected by the
delay
(as opposed to the decision itself). In addition, as the Board argues, since the time of the General Counsel’s original Legal Opinion (March 1983), Canadian employees have been on notice that service to American employers after the end of 1982 would in all likelihood not be included in benefits payments. Brief for Respondent at 34. The Board has therefore not placed Canadian employees in a position where benefits received during the Board’s deliberations must be repaid due to retroactive rescission of coverage. Petitioner’s claim of unreasonable delay is therefore untenable inasmuch as the Association does not seek further administrative action, and
there clearly was no prejudice to any affected party.
IV
We affirm the Board’s decision in the main and deny RLEA’s request for relief due to unreasonable delay. We vacate, however, the portion of the Board’s decision extending its application to elected union officials and remand to the Board for reconsideration of that issue in accordance with this opinion.
It is so ordered.