IBP, INC. v. ALVAREZ, individually and on behalf of all others similarly situated, et al.

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21 OCTOBER TERM, 2005
Syllabus
IBP, INC. v. ALVAREZ, individually and on behalf
of all others similarly situated, et al.
certiorari to the united states court of appeals for
the ninth circuit
No. 03–1238. Argued October 3, 2005—Decided November 8, 2005*
After this Court ruled that the term “workweek” in the Fair Labor Stand
ards Act of 1938 (FLSA) included the time employees spent walking
from time clocks near a factory entrance to their workstations, Ander
son v. Mt. Clemens Pottery Co., 328 U. S. 680, 691–692, Congress passed
the Portal-to-Portal Act of 1947, which, inter alia, excepted from FLSA
coverage walking on the employer’s premises to and from the location
of the employee’s “principal activity or activities,” § 4(a)(1), and activi
ties that are “preliminary or postliminary” to “said principal activity
or activities,” § 4(a)(2). The Act did not otherwise change this Court’s
descriptions of “work” and “workweek” or define “workday.” Regula
tions promulgated by the Secretary of Labor shortly thereafter con
cluded that the Act did not affect the computation of hours within a
“workday,” 29 CFR § 790.6(a), which includes “the period between the
commencement and completion” of the “principal activity or activities,”
§ 790.6(b). Eight years after the enactment of the Portal-to-Portal Act
and these interpretative regulations, the Court explained that the “term
‘principal activity or activities’ . . . embraces all activities which are ‘an
integral and indispensable part of the principal activities,’ ” including
the donning and doffing of specialized protective gear “before or after
the regular work shift, on or off the production line.” Steiner v. Mitch
ell, 350 U. S. 247, 256.
In No. 03–1238, respondent employees filed a class action seeking com
pensation for time spent donning and doffing required protective gear
and walking from the locker rooms to the production floor of a meat
processing facility owned by petitioner IBP, Inc. (IBP), and back. The
District Court found the activities compensable, and the Ninth Circuit
affirmed. In No. 04–66, petitioner employees sought compensation for
time spent donning and doffing required protective gear at a poultry
processing plant operated by respondent Barber Foods, Inc. (Barber),
*Together with No. 04–66, Tum et al. v. Barber Foods, Inc., dba Barber
Foods, on certiorari to the United States Court of Appeals for the First
Circuit.

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22 IBP, INC. v. ALVAREZ
Syllabus
as well as the attendant walking and waiting times. Barber prevailed
on the walking and waiting claims. On appeal, the First Circuit found
those times’ preliminary and postliminary activities excluded from
FLSA coverage by §§ 4(a)(1) and (2) of the Portal-to-Portal Act.
Held:
1. The time respondents in No. 03–1238 spend walking between
changing and production areas is compensable under the FLSA.
Pp. 30–37.
(a) Section 4(a)(1)’s text does not exclude such time from the
FLSA’s scope. IBP claims that, because donning is not the “principal
activity” that starts the workday, walking occurring immediately after
donning and immediately before doffing is not compensable. That argu
ment, which in effect asks for a third category of activities—those that
are “integral and indispensable” to a “principal activity” and thus not
excluded from coverage by § 4(a)(2), but are not themselves “principal
activities” as defined by § 4(a)(1)—is foreclosed by Steiner, which made
clear that § 4 does not remove activities that are “integral and indispen
sable” to “principal activities” from FLSA coverage precisely because
such activities are themselves “principal activities.” 350 U. S., at 253.
There is no plausible argument that these terms mean different things
in § 4(a)(2) and in § 4(a)(1). Under the normal rule of statutory inter
pretation, identical words used in different parts of the same statute
are generally presumed to have the same meaning; and in § 4(a)(2)’s
reference to “said principal activity or activities,” “said” is an explicit
reference to the use of the identical term in § 4(a)(1). Pp. 33–34.
(b) Also unpersuasive is IBP’s argument that Congress’ repudiation
of the Anderson holding reflects a purpose to exclude the walking time
at issue. That time, which occurs after the workday begins and before
it ends, is more comparable to time spent walking between two different
positions on an assembly line than to the walking in Anderson, which
occurred before the workday began. Pp. 34–35.
(c) The relevant regulations also support this view of walking.
Contrary to IBP’s claim, 29 CFR § 790.6 does not strictly define the
workday’s limits as the period from “whistle to whistle. ” And
§ 790.7(g), n. 49, which provides that postdonning walking time is not
“necessarily” excluded from § 4(a)(1)’s scope, does not mean that such
time is always excluded and is insufficient to overcome clear statements
in the regulations’ text that support the holding here. Pp. 35–37.
2. Because donning and doffing gear that is “integral and indispensa
ble” to employees’ work is a “principal activity” under the statute, the
continuous workday rule mandates that the time the No. 04–66 petition

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23 Cite as: 546 U. S. 21 (2005)
Syllabus
ers spend walking to and from the production floor after donning and
before doffing, as well as the time spent waiting to doff, are not affected
by the Portal-to-Portal Act, and are instead covered by the FLSA.
Pp. 37–40.
3. However, § 4(a)(2) excludes from the FLSA’s scope the time em
ployees spend waiting to don the first piece of gear that marks the be
ginning of the continuous workday. Such waiting—which is two steps
removed from the productive activity on the assembly line—comfort
ably qualifies as a “preliminary” activity. The fact that certain preshift
activities are necessary for employees to engage in their principal activi
ties does not mean that those preshift activities are “integral and indis
pensable” to a “principal activity” under Steiner. No limiting principle
allows this Court to conclude that the waiting time here is such an activ
ity without also leading to the logical (but untenable) conclusion that
the walking time in Anderson would also be a “principal activity” unaf
fected by the Portal-to-Portal Act. Title 29 CFR § 790.7(h) does not
support a contrary view. Pp. 40–42.
No. 03–1238, 339 F. 3d 894, affirmed; No. 04–66, 360 F. 3d 274, affirmed in
part, reversed in part, and remanded.
Stevens, J., delivered the opinion for a unanimous Court.
Carter G. Phillips argued the cause for petitioner in
No. 03–1238 and for respondent in No. 04–66. With him on
the briefs in No. 03–1238 were Joseph R. Guerra, Rebecca
K. Wood, Michael J. Mueller, and Joel M. Cohn. On the
brief in No. 04–66 was Graydon G. Stevens.
Thomas C. Goldstein argued the cause for petitioners in
No. 04–66 and for respondents in No. 03–1238. With him on
the briefs in No. 04–66 were Amy Howe, Kevin K. Russell,
Pamela S. Karlan, Timothy B. Fleming, Lori B. Kisch, and
William C. Nugent. On the brief in No. 03–1238 were
David N. Mark, William Rutzick, and Kathryn Goater.
Irving L. Gornstein argued the cause for the United
States as amicus cur iae supporting respondents in
No. 03–1238 and petitioners in No. 04–66. With him on the
brief were Solicitor General Clement, Deputy Solicitor

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24 IBP, INC. v. ALVAREZ
Opinion of the Court
General Hungar, Howard M. Radzely, Allen H. Feldman,
Steven J. Mandel, and Michael P. Doyle.†
Justice Stevens delivered the opinion of the Court.
These consolidated cases raise questions concerning the
coverage of the Fair Labor Standards Act of 1938 (FLSA),
as amended by the Portal-to-Portal Act of 1947, with respect
to activities of employees who must don protective clothing
on the employer’s premises before they engage in the pro
ductive labor for which they are primarily hired. The prin
cipal question, which is presented in both cases, is whether
the time employees spend walking between the changing
area and the production area is compensable under the
FLSA. The second question, which is presented only in
No. 04–66, is whether the time employees spend waiting to
put on the protective gear is compensable under the statute.
In No. 03–1238, the Court of Appeals for the Ninth Circuit
answered “yes” to the first question, 339 F. 3d 894 (2003); in
No. 04–66, the Court of Appeals for the First Circuit an
swered “no” to both questions, 360 F. 3d 274, 281 (2004). We
granted certiorari to resolve the conflict. 543 U. S. 1144
(2005).
†A brief of amici curiae urging reversal in No. 04–66 was filed for the
National Employment Lawyers Association et al. by Sandra Thourot
Kr ider, Mar issa M. Tirona, Patr icia A. Shiu, and Cather ine K.
Ruckelshaus.
Briefs of amici curiae urging reversal in No. 03–1238 and affirmance in
No. 04–66 were filed for the Chamber of Commerce of the United States
of America et al. by Samuel Estreicher, Meir Feder, Robin S. Conrad,
Robert Costagliola, and Quentin Riegel; and for the National Chicken
Council et al. by David R. Wylie and D. Christopher Lauderdale.
Jonathan P. Hiatt, James B. Coppess, and Laurence Gold filed a brief
for the American Federation of Labor and Congress of Industrial Organi
zations as amicus curiae urging reversal in No. 04–66 and affirmance in
No. 03–1238.

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Opinion of the Court
I
As enacted in 1938, the FLSA, 29 U. S. C. § 201 et seq.,
required employers engaged in the production of goods for
commerce to pay their employees a minimum wage of “not
less than 25 cents an hour,” § 6(a)(1), 52 Stat. 1062, and pro
hibited the employment of any person for workweeks in ex
cess of 40 hours after the second year following the legisla
tion “unless such employee receives compensation for his
employment in excess of [40] hours . . . at a rate not less
than one and one-half times the regular rate at which he
is employed,” id., § 7(a)(3), at 1063. Neither “work” nor
“workweek” is defined in the statute.1
Our early cases defined those terms broadly. In Tennes
see Coal, Iron & R. Co. v. Muscoda Local No. 123, 321 U. S.
590 (1944), we held that time spent traveling from iron ore
mine portals to underground working areas was compensa
ble; relying on the remedial purposes of the statute and Web
ster’s Dictionary, we described “work or employment” as
“physical or mental exertion (whether burdensome or not)
controlled or required by the employer and pursued neces
sarily and primarily for the benefit of the employer and his
business.” Id., at 598; see id., at 598, n. 11. The same year,
in Armour & Co. v. Wantock, 323 U. S. 126 (1944), we clari
fied that “exertion” was not in fact necessary for an activity
to constitute “work” under the FLSA. We pointed out that
“an employer, if he chooses, may hire a man to do nothing,
or to do nothing but wait for something to happen.” Id., at
133. Two years later, in Anderson v. Mt. Clemens Pottery
Co., 328 U. S. 680 (1946), we defined “the statutory work
week” to “includ[e] all time during which an employee is nec
essarily required to be on the employer’s premises, on duty
or at a prescribed workplace.” Id., at 690–691. Accord
1 The most pertinent definition provides: “ ‘Employ’ includes to suffer or
permit to work.” 52 Stat. 1060, 29 U. S. C. § 203(g).

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ingly, we held that the time necessarily spent by employees
walking from timeclocks near the factory entrance gate to
their workstations must be treated as part of the workweek.
Id., at 691–692.
The year after our decision in Anderson, Congress passed
the Portal-to-Portal Act, amending certain provisions of the
FLSA. Based on findings that judicial interpretations of
the FLSA had superseded “long-established customs, prac
tices, and contracts between employers and employees,
thereby creating wholly unexpected liabilities, immense in
amount and retroactive in operation,” 61 Stat. 84, it re
sponded with two statutory remedies, the first relating to
“existing claims,” id., at 85–86, and the second to “future
claims,” id., at 87–88. Both remedies distinguish between
working time that is compensable pursuant to contract or
custom and practice, on the one hand, and time that was
found compensable under this Court’s expansive reading of
the FLSA, on the other. Like the original FLSA, however,
the Portal-to-Portal Act omits any definition of the term
“work.”
With respect to existing claims, the Portal-to-Portal Act
provided that employers would not incur liability on account
of their failure to pay minimum wages or overtime compen
sation for any activity that was not compensable by either
an express contract or an established custom or practice.2
2 Part II of the Portal-to-Portal Act, entitled “existing claims,” states
in relevant part:
“Sec. 2. Relief From Certain Existing Claims Under the Fair
Labor Standards Act of 1938 . . . —
“(a) No employer shall be subject to any liability or punishment under
the Fair Labor Standards Act . . . (in any action or proceeding commenced
prior to or on or after the date of the enactment of this Act), on account
of the failure of such employer to pay an employee minimum wages, or to
pay an employee overtime compensation, for or on account of any activity
of an employee engaged in prior to the date of the enactment of this Act,
except an activity which was compensable by either—

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With respect to “future claims,” the Act preserved potential
liability for working time not made compensable by contract
or custom but narrowed the coverage of the FLSA by ex
cepting two activities that had been treated as compensable
under our cases: walking on the employer’s premises to and
from the actual place of performance of the principal activity
of the employee, and activities that are “preliminary or post
liminary” to that principal activity.
Specifically, Part III of the Portal-to-Portal Act, entitled
“future claims,” provides in relevant part:
“Sec. 4. Relief from Certain Future Claims
Under the Fair Labor Standards Act of 1938 . . . —
“(a) Except as provided in subsection (b) [which cov
ers work compensable by contract or custom], no em
ployer shall be subject to any liability or punishment
under the Fair Labor Standards Act of 1938, as
amended, . . . on account of the failure of such employer
to pay an employee minimum wages, or to pay an em
ployee overtime compensation, for or on account of any
of the following activities of such employee engaged in
on or after the date of the enactment of this Act—
“(1) walking, riding, or traveling to and from the ac
tual place of performance of the principal activity or
activities which such employee is employed to perform,
and
“(2) activities which are preliminary to or postlimi
nary to said principal activity or activities,
“(1) an express provision of a written or nonwritten contract in effect,
at the time of such activity, between such employee, his agent, or
collective-bargaining representative and his employer; or
“(2) a custom or practice in effect, at the time of such activity, at the
establishment or other place where such employee was employed, covering
such activity, not inconsistent with a written or nonwritten contract, in
effect at the time of such activity, between such employee, his agent, or
collective-bargaining representative and his employer.” 61 Stat. 85 (codi
fied at 29 U. S. C. § 252(a)).

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“which occur either prior to the time on any particular
workday at which such employee commences, or subse
quent to the time on any particular workday at which
he ceases, such principal activity or activities.” 61 Stat.
86–87 (codified at 29 U. S. C. § 254(a)).
Other than its express exceptions for travel to and from
the location of the employee’s “principal activity,” and for
activities that are preliminary or postliminary to that princi
pal activity, the Portal-to-Portal Act does not purport to
change this Court’s earlier descriptions of the terms “work”
and “workweek,” or to define the term “workday.” A regu
lation promulgated by the Secretary of Labor shortly after
its enactment concluded that the statute had no effect on the
computation of hours that are worked “within” the workday.
That regulation states: “[T]o the extent that activities en
gaged in by an employee occur after the employee com
mences to perform the first principal activity on a particular
workday and before he ceases the performance of the last
principal activity on a particular workday, the provisions of
[§ 4] have no application.” 29 CFR § 790.6(a) (2005).3 Simi
3 The regulation provides in full:
“Section 4 of the Portal Act does not affect the computation of hours
worked within the ‘workday’ proper, roughly described as the period ‘from
whistle to whistle,’ and its provisions have nothing to do with the compen
sability under the Fair Labor Standards Act of any activities engaged in
by an employee during that period. Under the provisions of section 4,
one of the conditions that must be present before ‘preliminary’ or ‘postlimi
nary’ activities are excluded from hours worked is that they ‘occur either
prior to the time on any particular workday at which the employee
commences, or subsequent to the time on any particular workday at which
he ceases’ the principal activity or activities which he is employed to per
form. Accordingly, to the extent that activities engaged in by an em
ployee occur after the employee commences to perform the first principal
activity on a particular workday and before he ceases the performance of
the last principal activity on a particular workday, the provisions of that
section have no application. Periods of time between the commencement
of the employee’s first principal activity and the completion of his last
principal activity on any workday must be included in the computation of

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larly, consistent with our prior decisions interpreting the
FLSA, the Department of Labor has adopted the continuous
workday rule, which means that the “workday” is generally
defined as “the period between the commencement and com
pletion on the same workday of an employee’s principal activ
ity or activities.” § 790.6(b). These regulations have re
mained in effect since 1947, see 12 Fed. Reg. 7658 (1947), and
no party disputes the validity of the continuous workday
rule.
In 1955, eight years after the enactment of the Portal-to-
Portal Act and the promulgation of these interpretive regu
lations, we were confronted with the question whether work
ers in a battery plant had a statutory right to compensation
for the “time incident to changing clothes at the beginning
of the shift and showering at the end, where they must make
extensive use of dangerously caustic and toxic materials, and
are compelled by circumstances, including vital considera
tions of health and hygiene, to change clothes and to shower
in facilities which state law requires their employers to
provide . . . .” Steiner v. Mitchell, 350 U. S. 247, 248 (1956).
After distinguishing “changing clothes and showering under
normal conditions” and stressing the important health and
safety risks associated with the production of batteries, id.,
at 249, the Court endorsed the Court of Appeals’ conclusion
that these activities were compensable under the FLSA.
In reaching this result, we specifically agreed with the
Court of Appeals that “the term ‘principal activity or ac
tivities’ in Section 4 [of the Portal-to-Portal Act] embraces
all activities which are an ‘integral and indispensable part of
hours worked to the same extent as would be required if the Portal Act
had not been enacted. The principles for determining hours worked
within the ‘workday’ proper will continue to be those established under
the Fair Labor Standards Act without reference to the Portal Act, which
is concerned with this question only as it relates to time spent outside
the ‘workday’ in activities of the kind described in section 4.” § 790.6(a)
(footnotes omitted).

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the principal activities,’ and that the activities in question
fall within this category.” Id., at 252–253. Thus, under
Steiner, activities, such as the donning and doffing of special
ized protective gear, that are “performed either before or
after the regular work shift, on or off the production line,
are compensable under the portal-to-portal provisions of the
Fair Labor Standards Act if those activities are an integral
and indispensable part of the principal activities for which
covered workmen are employed and are not specifically ex
cluded by Section 4(a)(1).” Id., at 256.
The principal question presented by these consolidated
cases—both of which involve required protective gear that
the courts below found integral and indispensable to the em
ployees’ work—is whether postdonning and predoffing walk
ing time is specifically excluded by § 4(a)(1). We conclude
that it is not.
II
Petitioner in No. 03–1238, IBP, Inc. (IBP), is a large pro
ducer of fresh beef, pork, and related products. At its plant
in Pasco, Washington, it employs approximately 178 workers
in 113 job classifications in the slaughter division and 800
line workers in 145 job classifications in the processing divi
sion. All production workers in both divisions must wear
outer garments, hardhats, hairnets, earplugs, gloves, sleeves,
aprons, leggings, and boots. Many of them, particularly
those who use knives, must also wear a variety of protective
equipment for their hands, arms, torsos, and legs; this gear
includes chain link metal aprons, vests, plexiglass arm
guards, and special gloves. IBP requires its employees to
store their equipment and tools in company locker rooms,
where most of them don their protective gear.
Production workers’ pay is based on the time spent cutting
and bagging meat. Pay begins with the first piece of meat
and ends with the last piece of meat. Since 1998, however,

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IBP has also paid for four minutes of clothes-changing time.4
In 1999, respondents, IBP employees, filed this class action
to recover compensation for preproduction and postproduc
tion work, including the time spent donning and doffing pro
tective gear and walking between the locker rooms and the
production floor before and after their assigned shifts.
After a lengthy bench trial, the District Court for the
Eastern District of Washington held that donning and
doffing of protective gear that was unique to the jobs at
issue were compensable under the FLSA because they were
integral and indispensable to the work of the employees who
wore such equipment. Moreover, consistent with the con
tinuous workday rule, the District Court concluded that, for
those employees required to don and doff unique protective
gear, the walking time between the locker room and the
production floor was also compensable because it occurs
during the workday.5 The court did not, however, allow any
recovery for ordinary clothes changing and washing, or for
the “donning and doffing of hard hat[s], ear plugs, safety
glasses, boots [or] hairnet[s].” App. to Pet. for Cert. in
No. 03–1238, p. 65a.
The District Court proceeded to apply these legal conclu
sions in making detailed factual findings with regard to the
different groups of employees. For example, the District
4 IBP does not contend that this clothes-changing time fully compen
sated respondents for the preproduction and postproduction time at issue
in this case.
5 The District Court explained:
“Walking time is compensable if it occurs after the start of the workday.
29 U. S. C. § 254(a). Walking time is excluded under the Portal to Portal
Act only if it occurs ‘either prior to the time on any particular work day
at which such employee commences or subsequent to the time on any par
ticular work day at which he ceases such principal activity or activities.’
Id. The work day begins with the commencement of an employee’s prin
cipal activity or activities and ends with the completion of the employee’s
activity . . . .” App. to Pet. for Cert. in No. 03–1238, pp. 53a–54a.

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Court found that, under its view of what was covered by
the FLSA, processing division knife users were entitled to
compensation for between 12 and 14 minutes of preproduc
tion and postproduction work, including 3.3 to 4.4 minutes of
walking time.
The Court of Appeals agreed with the District Court’s ul
timate conclusions on these issues, but in part for different
reasons. 339 F. 3d 894 (CA9 2003). After noting that the
question whether activities “ ‘are an integral and indispensa
ble part of the principal activities’ ” within the meaning of
Steiner is “context specific,” 339 F. 3d, at 902, the Court of
Appeals endorsed the distinction between the burdensome
donning and doffing of elaborate protective gear, on the one
hand, and the time spent donning and doffing nonunique gear
such as hardhats and safety goggles, on the other. It did so
not because donning and doffing nonunique gear are categor
ically excluded from being “principal activities” as defined
by the Portal-to-Portal Act, but rather because, in the con
text of this case, the time employees spent donning and
doffing nonunique protective gear was “ ‘de minimis as a
matter of law.’ ” Id., at 904.
IBP does not challenge the holding below that, in light of
Steiner, the donning and doffing of unique protective gear
are “principal activities” under § 4 of the Portal-to-Portal
Act. Moreover, IBP has not asked us to overrule Steiner.
Considerations of stare decisis are particularly forceful in the
area of statutory construction, especially when a unanimous
interpretation of a statute has been accepted as settled law
for several decades. Thus, the only question for us to decide
is whether the Court of Appeals correctly rejected IBP’s
contention that the walking between the locker rooms and
the production areas is excluded from FLSA coverage by
§ 4(a)(1) of the Portal-to-Portal Act.
IBP argues that the text of § 4(a)(1), the history and pur
pose of its enactment, and the Department of Labor’s inter
pretive guidance compel the conclusion that the Portal-to

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Portal Act excludes this walking time from the scope of the
FLSA. We find each of these arguments unpersuasive.
Text
IBP correctly points out that our decision in Steiner held
only that the donning and doffing of protective gear in that
case were activities “integral and indispensable” to the
workers’ principal activity of making batteries. 350 U. S.,
at 256. In IBP’s view, a category of “integral and indispen
sable” activities that may be compensable because they are
not merely preliminary or postliminary within the meaning
of § 4(a)(2) is not necessarily coextensive with the actual
“principal activities” which the employee “is employed to
perform” within the meaning of § 4(a)(1). In other words,
IBP argues that, even though the court below concluded that
donning and doffing of unique protective gear are “integral
and indispensable” to the employees’ principal activity, this
means only that the donning and doffing of such gear are
themselves covered by the FLSA. According to IBP, the
donning is not a “principal activity” that starts the workday,
and the walking that occurs immediately after donning and
immediately before doffing is not compensable. In effect,
IBP asks us to create a third category of activities—those
that are “integral and indispensable” to a “principal activity”
and thus not excluded from coverage by § 4(a)(2), but that
are not themselves “principal activities” as that term is de
fined by § 4(a)(1).
IBP’s submission is foreclosed by Steiner. As noted
above, in Steiner we made it clear that § 4 of the Portal-to-
Portal Act does not remove activities which are “ ‘integral
and indispensable’ ” to “ ‘principal activities’ ” from FLSA
coverage precisely because such activities are themselves
“ ‘principal activities.’ ” Id., at 253. While Steiner specifi
cally addressed the proper interpretation of the term “prin
cipal activity or activities” in § 4(a)(2), there is no plausible
argument that these terms mean something different in

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34 IBP, INC. v. ALVAREZ
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§ 4(a)(2) than they do in § 4(a)(1).6 This is not only because
of the normal rule of statutory interpretation that identical
words used in different parts of the same statute are gener
ally presumed to have the same meaning. E. g., Sullivan v.
Stroop, 496 U. S. 478, 484 (1990). It is also because § 4(a)(2)
refers to “said principal activity or activities.” 61 Stat. 87
(emphasis added). The “said” is an explicit reference to the
use of the identical term in § 4(a)(1).
Indeed, IBP has not offered any support for the unlikely
proposition that Congress intended to create an intermediate
category of activities that would be sufficiently “principal”
to be compensable, but not sufficiently principal to commence
the workday. Accepting the necessary import of our holding
in Steiner, we conclude that the locker rooms where the spe
cial safety gear is donned and doffed are the relevant “place
of performance” of the principal activity that the employee
was employed to perform within the meaning of § 4(a)(1).
Walking to that place before starting work is excluded from
FLSA coverage, but the statutory text does not exclude
walking from that place to another area within the plant im
mediately after the workday has commenced.
Purpose
IBP emphasizes that our decision in Anderson v. Mt.
Clemens Pottery Co., 328 U. S. 680, may well have been the
proximate cause of the enactment of the Portal-to-Portal
Act. In that case we held that the FLSA mandated compen
sation for the time that employees spent walking from time
clocks located near the plant entrance to their respective
places of work prior to the start of their productive labor.
Id., at 690–691. In IBP’s view, Congress’ forceful repudia
6 In fact, as noted above, in Steiner we specifically endorsed the view of
the Court of Appeals that the definition of “principal activity or activities”
in § 4 encompassed activities “ ‘integral and indispensable’ ” to those prin
cipal activities. We did not make any distinction between § 4(a)(1) and
§ 4(a)(2). 350 U. S., at 253.

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tion of that holding reflects a purpose to exclude what IBP
regards as the quite similar walking time spent by respond
ents before and after their work slaughtering cattle and
processing meat. Even if there is ambiguity in the statute,
we should construe it to effectuate that important purpose.
This argument is also unpersuasive. There is a critical
difference between the walking at issue in Anderson and
the walking at issue in this case. In Anderson the walking
preceded the employees’ principal activity; it occurred before
the workday began. The relevant walking in this case oc
curs after the workday begins and before it ends. Only if
we were to endorse IBP’s novel submission that an activity
can be sufficiently “principal” to be compensable, but not suf
ficiently so to start the workday, would this case be compara
ble to Anderson.
Moreover, there is a significant difference between the
open-ended and potentially expansive liability that might re
sult from a rule that treated travel before the workday be
gins as compensable, and the rule at issue in this case. In
deed, for processing division knife users, the largest segment
of the work force at IBP’s plant, the walking time in dispute
here consumes less time than the donning and doffing activi
ties that precede or follow it. It is more comparable to time
spent walking between two different positions on an assem
bly line than to the prework walking in Anderson.
Regulations
The regulations adopted by the Secretary of Labor in 1947
support respondents’ view that when donning and doffing of
protective gear are compensable activities, they may also de
fine the outer limits of the workday. Under those regula
tions, the few minutes spent walking between the locker
rooms and the production area are similar to the time spent
walking between two different workplaces on the disassem
bly line. See 29 CFR § 790.7(c) (2005) (explaining that the
Portal-to-Portal Act does not affect the compensability of

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36 IBP, INC. v. ALVAREZ
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time spent traveling from the place of performance of one
principal activity to that of another). See also § 785.38 (ex
plaining, in a later regulation interpreting the FLSA, that
“[w]here an employee is required to report at a meeting place
to receive instructions or to perform other work there, or to
pick up and to carry tools, the travel from the designated
place to the work place is part of the day’s work, and must
be counted as hours worked . . . ”).
IBP argues, however, that two provisions in the regula
tions point to a different conclusion—the use of the phrase
“whistle to whistle” in discussing the limits of the “workday,”
§ 790.6, and a footnote stating that postchanging walking
time is not “necessarily” excluded from the scope of § 4(a)(1),
§ 790.7(g), n. 49.
The “whistle to whistle” reference does reflect the view
that in most situations the workday will be defined by the
beginning and ending of the primary productive activity.
But the relevant text describes the workday as “roughly
the period ‘from whistle to whistle.’ ” § 790.6(a) (emphasis
added). Indeed, the next subsection of this same regulation
states: “ ‘Workday’ as used in the Portal Act means, in gen
eral, the period between the commencement and completion
on the same workday of an employee’s principal activity or
activities.” § 790.6(b). IBP’s emphasis on the “whistle to
whistle” reference is unavailing.
The footnote on which IBP relies states:
“Washing up after work, like the changing of clothes,
may in certain situations be so directly related to the
specific work the employee is employed to perform that
it would be regarded as an integral part of the em
ployee’s ‘principal activity.’ This does not necessarily
mean, however, that travel between the washroom or
clothes-changing place and the actual place of perform
ance of the specific work the employee is employed to
perform, would be excluded from the type of travel to

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which section 4(a) refers.” § 790.7(g), n. 49 (emphasis
added; citations omitted).
This footnote does indicate that the Secretary assumed
that there would be some cases in which walking between a
locker room where the employee performs her first principal
activity and the production line would be covered by the
FLSA and some cases in which it would not be. That as
sumption is, of course, inconsistent with IBP’s submission
that such walking is always excluded by § 4(a), just as it is
inconsistent with respondents’ view that such walking is
never excluded. Whatever the correct explanation for the
Secretary’s ambiguous (and apparently ambivalent) state
ment may be, it is not sufficient to overcome the clear state
ments in the text of the regulations that support our holding.
And it surely is not sufficient to overcome the statute itself,
whose meaning is definitively resolved by Steiner.
For the foregoing reasons, we hold that any activity that
is “integral and indispensable” to a “principal activity” is it
self a “principal activity” under § 4(a) of the Portal-to-Portal
Act. Moreover, during a continuous workday, any walking
time that occurs after the beginning of the employee’s first
principal activity and before the end of the employee’s last
principal activity is excluded from the scope of that provi
sion, and as a result is covered by the FLSA.
III
Respondent in No. 04–66, Barber Foods, Inc. (Barber), op
erates a poultry processing plant in Portland, Maine, that
employs about 300 production workers. These employees
operate six production lines and perform a variety of tasks
that require different combinations of protective clothing.
They are paid by the hour from the time they punch in to
computerized timeclocks located at the entrances to the pro
duction floor.
Petitioners are Barber employees and former employees
who brought this action to recover compensation for alleged

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unrecorded work covered by the FLSA. Specifically, they
claimed that Barber ’s failure to compensate them for
(a) donning and doffing required protective gear and (b) the
attendant walking and waiting violated the statute.
After extensive discovery, the Magistrate Judge issued a
comprehensive opinion analyzing the facts in detail, and rec
ommending the entry of partial summary judgment in favor
of Barber. That opinion, which was later adopted by the
District Court for Maine, included two critical rulings.
First, the Magistrate Judge held that “the donning and
doffing of clothing and equipment required by the defendant
or by government regulation, as opposed to clothing and
equipment which employees choose to wear or use at their
option, is an integral part of the plaintiffs’ work [and there
fore are] not excluded from compensation under the Portal
to-Portal Act as preliminary or postliminary activities.”
App. to Pet. for Cert. in No. 04–66, pp. 36a–40a.
Second, the Magistrate Judge rejected petitioners’ claims
for “compensation for the time spent before obtaining their
clothing and equipment.” Id., at 33a. Such time, in the
Magistrate Judge’s view, “could [not] reasonably be con
strued to be an integral part of employees’ work activities
any more than walking to the cage from which hairnets and
earplugs are dispensed . . . .” Ibid. Accordingly, Barber
was “entitled to summary judgment on any claims based on
time spent walking from the plant entrances to an employ
ee’s workstation, locker, time clock or site where clothing
and equipment required to be worn on the job is to be ob
tained and any claims based on time spent waiting to punch
in or out for such clothing or equipment.” Id., at 33a–34a.
The Magistrate Judge’s opinion did not specifically address
the question whether the walking time between the produc
tion line and the place of donning and doffing was encom
passed by § 4 of the Portal-to-Portal Act, and thus excluded
from coverage under the FLSA. Whatever the intended
scope of the Magistrate’s grant of partial summary judg

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ment, the questions submitted to the jury after trial asked
jurors to consider only whether Barber was required to com
pensate petitioners for the time they spent actually donning
and doffing various gear.
Before the case was submitted to the jury, the parties stip
ulated that four categories of workers—rotating, setup,
meatroom, and shipping and receiving associates—were re
quired to don protective gear at the beginning of their shifts
and were required to doff this gear at the end of their shifts.
The jury then made factual findings with regard to the
amount of time reasonably required for each category of em
ployees to don and doff such items; the jury concluded that
such time was de minimis and therefore not compensable.
The jury further concluded that two other categories of em
ployees—maintenance and sanitation associates—were not
required to don protective gear before starting their shifts.7
Accordingly, the jury ruled for Barber on all counts.
On appeal, petitioners argued, among other things, that
the District Court had improperly excluded as noncompensa
ble the time employees spend walking to the production floor
after donning required safety gear and the time they spend
walking from the production floor to the area where they
doff such gear. The Court of Appeals rejected petitioners’
argument, concluding that such walking time was a spe
cies of preliminary and postliminary activity excluded from
FLSA coverage by §§ 4(a)(1) and (2) of the Portal-to-Portal
Act. 360 F. 3d, at 281. As we have explained in our discus
sion of IBP’s submission, see Part II, supra, that categorical
conclusion was incorrect.
Petitioners also argued in the Court of Appeals that the
waiting time associated with the donning and doffing of
clothes was compensable. The Court of Appeals disagreed,
holding that the waiting time qualified as a “preliminary or
postliminary activity” and thus was excluded from FLSA
7 The claims brought by these workers are no longer part of this case.

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coverage by the Portal-to-Portal Act. 360 F. 3d, at 282.
Our analysis in Part II, supra, demonstrates that the Court
of Appeals was incorrect with regard to the predoffing wait
ing time. Because doffing gear that is “integral and indis
pensable” to employees’ work is a “principal activity” under
the statute, the continuous workday rule mandates that time
spent waiting to doff is not affected by the Portal-to-Portal
Act and is instead covered by the FLSA.
The time spent waiting to don—time that elapses before
the principal activity of donning integral and indispensa
ble gear—presents the quite different question whether it
should have the effect of advancing the time when the work
day begins. Barber argues that such predonning waiting
time is explicitly covered by § 4(a)(2) of the Portal-to-Portal
Act, which, as noted above, excludes “activities which are
preliminary to or postliminary to [a] principal activity or ac
tivities” from the scope of the FLSA. 29 U. S. C. § 254(a)(2).
By contrast, petitioners, supported by the United States
as amicus curiae, maintain that the predonning waiting time
is “integral and indispensable” to the “principal activity” of
donning, and is therefore itself a principal activity. How
ever, unlike the donning of certain types of protective gear,
which is always essential if the worker is to do his job, the
waiting may or may not be necessary in particular situations
or for every employee. It is certainly not “integral and in
dispensable” in the same sense that the donning is. It does,
however, always comfortably qualify as a “preliminary”
activity.
We thus do not agree with petitioners that the predonning
waiting time at issue in this case is a “principal activity”
under § 4(a).8 As Barber points out, the fact that certain
preshift activities are necessary for employees to engage in
their principal activities does not mean that those preshift
activities are “integral and indispensable” to a “principal ac
8 As explained below, our analysis would be different if Barber required
its employees to arrive at a particular time in order to begin waiting.

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tivity” under Steiner. For example, walking from a time
clock near the factory gate to a workstation is certainly
necessary for employees to begin their work, but it is
indisputable that the Portal-to-Portal Act evinces Congress’
intent to repudiate Anderson’s holding that such walking
time was compensable under the FLSA. We discern no lim
iting principle that would allow us to conclude that the wait
ing time in dispute here is a “principal activity” under § 4(a),
without also leading to the logical (but untenable) conclusion
that the walking time at issue in Anderson would be a “prin
cipal activity” under § 4(a) and would thus be unaffected by
the Portal-to-Portal Act.
The Government also relies on a regulation promulgated
by the Secretary of Labor as supporting petitioners’ view.
That regulation, 29 CFR § 790.7(h) (2005), states that when
an employee “is required by his employer to report at a par
ticular hour at his workbench or other place where he
performs his principal activity, if the employee is there at
that hour ready and willing to work but for some reason
beyond his control there is no work for him to perform until
some time has elapsed, waiting for work would be an integral
part of the employee’s principal activities.” That regulation
would be applicable if Barber required its workers to report
to the changing area at a specific time only to find that no
protective gear was available until after some time had
elapsed, but there is no such evidence in the record in this
case.
More pertinent, we believe, is the portion of § 790.7 that
characterizes the time that employees must spend waiting to
check in or waiting to receive their paychecks as generally a
“preliminary” activity covered by the Portal-to-Portal Act.
See § 790.7(g). That regulation is fully consistent with the
statutory provisions that allow the compensability of such
collateral activities to depend on either the agreement of the
parties or the custom and practice in the particular industry.

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In short, we are not persuaded that such waiting—which
in this case is two steps removed from the productive activ
ity on the assembly line—is “integral and indispensable” to
a “principal activity” that identifies the time when the con
tinuous workday begins. Accordingly, we hold that § 4(a)(2)
excludes from the scope of the FLSA the time employees
spend waiting to don the first piece of gear that marks the
beginning of the continuous workday.
IV
For the reasons stated above, we affirm the judgment of
the Court of Appeals for the Ninth Circuit in No. 03–1238.
We affirm in part and reverse in part the judgment of the
Court of Appeals for the First Circuit in No. 04–66, and we
remand the case for further proceedings consistent with
this opinion.
It is so ordered.