PUBLISH 

UNITED STATES COURT OF APPEALS 

FOR THE TENTH CIRCUIT 

_________________________________ 

ESMERALDA CASTANEDA; JOSHUA 

J. PETERS; ANDREW RUIZ; 

ANGELICA GUTIERREZ; JOANN S. 

LOPEZ; MARIANO GALLEGOS; TIM 

PRAEUNER; DAWN ALLMER; 

SAMUEL SANCHEZ; ADAN 

ABDULLAHI; AMINO N. GALAL; 

ISTAHIL FARAH JAMA; ABDIRIZAK 

M. ABDI; MUHYADIN AU; MOHAMED 

HOROR; HABIBO A. ELMI; HIBO H. 

MAALIN; FAIUMA JAMA; BATULA 

AWL; SADI M. ADAN; ABDIRIZAK 

AHMED; AHMED ALI GELLE; 

HABIBA ABDI; KURESHA S. NOOR; 

MOHAMED ISSE; MOHAMED A. 

MOHAMED; ABDI ABDIRAHMAN; 

MOHAMED MOHAMED; MOHAMED 

BUROW; ISRAD IBRAHIM; ABDI 

JAMA; ABDIAZIZ OSMAN; IBRAHIM 

O. HASSAN; NUR A. ABDULLAHI; 

ABDUL KADIR ALI; NUR B. SHUBE; 

ABDIAMAR BARE; SUHAN JAMA; 

HASSAN FARAH; NAJIMA HANDULE; 

AHMED SIRAD ABDI; ALI ABDI; 

ABDULLAHI ABDIVAHMAN; 

SALEBAN AHMED; ABDIMAHAT ALI; 

MANUEL GALLEGOU; ABDIRAHMAN 

HASSAN; SADIYO HASSAN; NIMC 

MOHAMED; ALI AHMED MUSE; 

NIMO OMAR; ABDUL PATAH; 

ASHLEY TAYLOR; SAHRO JAMA; 

FARDOWSA ALI; IBRAHIM A. IMAN; 

AHMED KHALIF; IRAQ I. ABADE; 

MOHAMED F. JAMA; MOHAMUD 

MOHAMED AHMED; ANAB ABDI; 

HAJI ALI MOHAMUD; KAMAL 

Nos. 14-1217 and 14-1221 

 

FILED 

United States Court of Appeals

Tenth Circuit 

March 31, 2016

Elisabeth A. Shumaker 

Clerk of Court
2 

SALAH; FARDOWSA ANSHUR; 

SAHRA NUR; TAJIR HERSI, 

 Plaintiffs - Appellants / Cross-

 Appellees, 

v. 

JBS USA, LLC, 

 Defendant - Appellee / Cross-

 Appellant, 

and 

SWIFT BEEF COMPANY; SWIFT & 

COMPANY, INC.; JBS SWIFT & 

COMPANY; JBS S.A., 

 Defendants. 

_________________________________ 

Appeal from the United States District Court 

for the District of Colorado 

(D.C. No. 1:08-CV-01833-RPM)

_________________________________ 

Robert L. Wiggins,Jr., Wiggins, Childs, Pantazis, Fisher & Goldfarb, Birmingham, 

Alabama (Robert J. Camp, Wiggins, Childs, Pantazis, Fisher & Goldfarb, Birmingham, 

Alabama, Diane Vaksdal Smith, Burg Simpson Eldredge Hersh & Jardine, P.C., 

Englewood, Colorado, and Joseph D. Lane, The Cochran Law Firm, P.C., Dothan, 

Alabama, with him on the briefs for Plaintiffs-Appellants/Cross-Appellees. 

W.V. Bernie Siebert, Sherman & Howard, L.L.C., Denver, Colorado (Kelly K. Robinson, 

Sherman & Howard, L.L.C., Denver, Colorado and Lori M. Phillips, Sherman & 

Howard, L.L.C., Atlanta, Georgia, with him on the briefs), for DefendantAppellee/Cross-Appellant. 

_________________________________ 

Before KELLY, HARTZ, and GORSUCH, Circuit Judges. 

_________________________________ 

HARTZ, Circuit Judge. 
3 

_________________________________ 

Plaintiffs are current and former hourly employees in the slaughter and fabrication 

operations of a beef-processing plant in Greeley, Colorado, now owned by JBS USA, 

LLC (JBS). Employees on the slaughter line kill the cattle and disassemble them into 

sides of beef; employees on the fabrication line cut the sides into various beef products. 

Plaintiffs have been paid under the terms of collective-bargaining agreements negotiated 

between the United Food and Commercial Workers International Union (the Union) and 

JBS. (For convenience we will refer to both JBS and its predecessors as JBS.) 

Plaintiffs filed suit against JBS in October 2010, claiming that they did not receive 

compensation required by the Fair Labor Standards Act (FLSA). The disputes concern 

when the work day begins, when it ends, and what, if any, compensation is due when the 

production lines halt for a 30-minute meal break. After a bench trial the United States 

District Court for the District of Colorado found that Plaintiffs had failed to carry their 

burden of proof and entered judgment in favor of JBS. Exercising jurisdiction under 

28 U.S.C. § 1291, we affirm. The court could properly find that compensation for 

Plaintiffs’ activities complied with the FLSA. 

I. BACKGROUND 

A. Introduction to the Legal Framework 

The FLSA typically requires an employer to compensate employees for all the 

time that the employee spends working on the employer’s behalf. See Smith v. Aztec 

Well Servicing Co., 462 F.3d 1274, 1285 (10th Cir. 2006). The FLSA does not define 

work, see Smith, 462 F.3d at 1285, but the Supreme Court has defined the term in the 
4 

FLSA as “physical or mental exertion (whether burdensome or not) controlled or required 

by the employer and pursued necessarily and primarily for the benefit of the employer 

and his business,” Tenn. Coal, Iron & R. Co. v. Muscoda Local N. 123, 321 U.S. 590, 598 

(1944) (emphasis added). 

One issue that has been the source of many disputes is when the work day begins 

and ends. A partial solution is provided by § 4(a) of the Portal-to-Portal Act of 1947, 

under which commute time and walking to and from the employee’s work station is 

ordinarily noncompensable. It provides that the term work does not include either (1) 

walking or travel time to and from the employee’s “actual place of performance of the 

principal activity or activities which [the] employee is employed to perform” or (2) 

“activities which are preliminary to or postliminary to said principal activity or 

activities.” 29 U.S.C. § 254(a). The Act leaves open to dispute, however, what is 

encompassed by the term principal activity. The Supreme Court has explained that 

“activities performed either before or after the regular work shift, on or off the production 

line, are compensable . . . if those activities are an integral and indispensable part of the 

principal activities for which covered workmen are employed and are not specifically 

excluded by Section 4(a)(1).” Steiner v. Mitchell, 350 U.S. 247, 256 (1956) (time that 

battery-plant employees exposed to toxic chemicals spent changing clothes and 

showering pre- and post-shift was compensable). In other words, “any activity that is 

integral and indispensable to a principal activity is itself a principal activity.” IBP, Inc. v. 

Alvarez, 546 U.S. 21, 37 (2005) (internal quotation marks omitted). 
5 

To avoid some of the remaining points of controversy, Congress has left a few 

matters to collective bargaining. After a Department of Labor interpretive bulletin said 

that changing clothes, at least in some circumstances, could be an integral part of a 

worker’s principal activity (and therefore compensable, as confirmed in Steiner, 350 U.S. 

at 256), Congress enacted 29 U.S.C. § 203(o). See Sandifer v. U.S. Steel Corp., 134 S. 

Ct. 870, 875–76 (2014). Under that statute a collective-bargaining agreement can 

provide that changing clothes and washing at the beginning and end of the work day are 

not compensable. The parties have disputed what activities (such as donning (and 

doffing) protective gear and picking up (and disposing of) equipment) can be 

encompassed by this exclusion from compensation. And they have also disputed whether 

workers must be compensated for their walk time between the locker rooms (where they 

don and doff clothing) and the production lines. We will discuss the applicable law in 

greater detail below. 

Another ground for ignoring some activities at the beginning and end of the work 

day is the de minimis doctrine, which originated in Anderson v. Mt. Clemens Pottery Co., 

328 U.S. 680, 692 (1946). “When the matter in issue concerns only a few seconds or 

minutes of work beyond the scheduled working hours, such trifles may be disregarded. 

Split-second absurdities are not justified by the actualities of working conditions or by 

the policy of the [FLSA].” Id. The de minimis doctrine has been codified (and limited, 

see Sandifer, 134 S. Ct. at 880 n.8) by the Department of Labor, which has promulgated a 

rule stating that “insubstantial or insignificant periods of time beyond the scheduled 

working hours, which cannot as a practical administrative matter be precisely recorded 
6 

for payroll purposes, may be disregarded,” 29 C.F.R. § 785.47, although “[a]n employer 

may not arbitrarily fail to count as hours worked any part, however small, of the 

employee’s fixed or regular working time or practically ascertainable period of time he is 

regularly required to spend on duties assigned to him.” Id.; see Reich v. Monfort, 

144 F.3d 1329, 1333–34 (10th Cir. 1998) (adopting three-factor test to determine whether 

time is de minimis: “(1) the practical administrative difficulty of recording the additional 

time; (2) the size of the claim in the aggregate; and (3) whether the claimants performed 

the work on a regular basis”); id. at 1333 (“There is no precise amount of time that may 

be denied compensation as de minimis.”). 

Once the work day starts, all activity is ordinarily compensable until the work day 

ends. Under the continuous-workday rule promulgated by the Secretary of Labor: “[T]o 

the extent that activities engaged in by an employee 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 [§ 4 

of the Portal-to-Portal Act] have no application.” 29 C.F.R. § 790.6(a); see Alvarez, 

546 U.S. at 28. That is, an activity (such as walking to or from a work station) that 

occurs between the first and last principal activities of the day is compensable even if that 

same activity would be excluded from compensable time under the Portal-to-Portal Act 

had it occurred before the first or after the last principal activity of the day. See Alvarez, 

546 U.S. at 37. 

One exception to the continuous-workday rule is at issue in this litigation. The 

employer does not need to compensate employees for a bona fide meal break, which is 
7 

ordinarily at least 30 minutes. See 29 C.F.R. § 785.19(a). The parties have disputed 

whether certain activities at the beginning and end of the 30-minute meal breaks at the 

JBS plant are compensable work and even whether the break meets the requirement for a 

bona fide meal break. Again, we will discuss the applicable law in more detail below. 

B. Work at the Plant and Agreement with the Union 

To prevent contamination of beef products, government regulations and JBS rules 

require workers to wear hair nets, beard nets, plastic aprons, plastic gloves, plastic 

sleeves, cotton gloves, frocks, and surgical scrubs. For worker safety, they are also 

required to wear personal protective equipment such as boots, scabbards, mesh protective 

equipment, cut-resistant gloves, hard hats, ear plugs, and safety glasses. At the beginning 

of each day, employees go to their lockers to retrieve and put on such items and to 

retrieve their knives, hooks, and steels. (All Plaintiffs have wielded knives in their JBS 

jobs.) They then proceed to the production floor. Plaintiffs, depending on their job 

duties, obtain frocks, cotton and cut-resistant gloves, and scrubs from supply windows 

and sanitize their boots, hands, knives, hooks, and mesh gloves. Knife-wielding 

employees may sharpen their knives in the knife room. 

When they leave the production line at the end of the shift, employees remove 

their equipment and sanitary clothing. They return their frocks, cotton and cut-resistant 

gloves, and scrubs to their designated areas. They wash their personal protective and 

sanitary equipment at wash stations and then sanitize it in special tanks. Id. They must 

also sanitize their hands and boots before walking to the locker room to store clothing 

and equipment. 
8 

Employees perform similar tasks at the beginning and end of their meal break. 

They remove their equipment and sanitary clothing, except for their hard hats, hair nets, 

beard nets, ear plugs, and safety glasses. They walk to a wash station to wash their boots 

and sanitize their hands and boots. Fabrication employees also turn in their cotton 

gloves. Before returning to the lines, employees must sanitize their boots and hands and 

put back on what they had removed. 

Under a timekeeping practice known as gang time (also sometimes referred to as 

line time or master time) employees are paid from the time the first product arrives on the 

production line until the last product leaves the line. A supervisor and a union 

representative track the time. No one records activities employees perform off the 

production line at the beginning and end of the shift and during the meal break, so 

employees are free to socialize and loiter. 

In 2000, in an effort to compensate employees for some of the unmeasured 

activities, JBS and the Union each hired an industrial engineer to calculate the time 

needed to don and doff safety clothing and equipment at the beginning and end of the 

shift and at meal time, and, at the end of the shift, walk to the wash area to clean safety 

clothing and equipment, wait at the wash area, and wash safety equipment. These studies 

did not account for increased walk times caused by waiting, obstructions, and congestion. 

JBS and the Union agreed to incorporate the measured times for the tasks, called plug 

times, into their 2000 agreement as compensable time. The agreement did not, however, 

account for walk time from the wash area to the locker room at the end of the day or any 

walk time at the beginning of the day. The time devoted to activities compensated by 
9 

plug times are not measured each day for each employee. Rather, the employee is 

compensated by “plugging in” the precalculated time for the employee (depending on the 

employee’s specific job)—that is, adding it to the measured amount of work time. 

The parties later incorporated the 2000 plug times into their collective-bargaining 

agreement that was effective from 2004 through 2009. In 2007 the Union and JBS again 

engaged industrial engineers to measure the time it took employees to complete various 

tasks. This time JBS’s engineer used a process called Ease Works that measured the 

various movements it took to complete a task. For instance, when measuring how long it 

would take to put on a mesh apron the engineer would add together the times it took to 

reach out, grab the mesh, lift the mesh, etc. To identify the various components of each 

task, the engineer observed videos of employees performing the tasks. The Union’s 

engineer, however, again calculated times by measuring how long it took employees to 

complete the tasks on the production floor. During their 2007 studies the engineers also 

measured how long it took for employees to walk from the center of the locker room to 

the center of the production floor. 

JBS and the Union reached an agreement in 2010 to continue to compensate 

employees as provided in the 2000 agreement but negotiated additional plug time to 

account for pre- and post-shift walking between the locker room and the production floor 

by using for all employees the distance between the center of the locker room and the 

center of the production floor. Neither party has pointed us to the calculations underlying 

the 2010 plug-time payments and they do not appear to be in the record. As part of this 

negotiated agreement, JBS agreed to pay current employees the additional time 
10 

retroactively for the preceding two-year period of November 2007 to November 2009. 

Those no longer employed were not paid retroactive walk time. 

C. The Litigation 

Before the 2010 agreement, on August 27, 2008, Plaintiffs filed the present 

putative collective action against JBS under the FLSA. In an FLSA collective action an 

aggrieved employee can bring a claim against an employer on behalf of himself “and 

other employees similarly situated.” 29 U.S.C. § 216(b). To become a party, an 

employee must opt in by “giv[ing] his consent in writing.” Id.; see Hoffmann-La Roche 

Inc. v. Sperling, 493 U.S. 165, 173 (1989). 

Plaintiffs’ complaint contended that they had not been adequately compensated for 

pre- and post-shift “time spent donning and doffing clothing and protective gear, washing 

[equipment and themselves], and walking to and from their job posts,” Aplt. App. I at 

117. They also sought compensation for their entire meal break on the ground that it was 

not a bona fide meal break, or at least for their time donning, doffing, washing, and 

walking at the beginning and the end of meal breaks. They requested damages for 

uncompensated work going back two or three years before they filed their complaint in 

2008. (Undercompensated employees ordinarily must bring a claim to recover unpaid 

wages within two years of accrual of the claim. See 29 U.S.C. § 255(a). But if the 

employer willfully violated the FLSA, the limitations period is extended to three years. 

See id.) 

The district court granted partial summary judgment to JBS, ruling that Plaintiffs’ 

claim for pre- and post-shift changing of clothes was noncompensable under 29 U.S.C. § 
11 

203(o) because it was covered by the collective-bargaining agreement. The parties 

proceeded to a two-phase bench trial on Plaintiffs’ claims that they were not reasonably 

compensated for (1) pre- and post-shift waiting, walking, and transporting tools; and (2) 

mealtime walking, transporting, waiting, washing, and donning and doffing. 

In the first phase of the bench trial the parties agreed to limit their evidence to 

liability issues. Based on video evidence of plant operations, the district court found that 

there were “substantial amounts of time required in walking from the locker rooms to the 

assigned positions on the lines and waiting because of congestion in their areas before the 

beginning and ending of the work performed on the lines.” Aplt. Add. at 9–10 (First 

Order – Doc. 166). The court also found that JBS “has not provided a full 30 minute 

meal break and the minimal amounts of plug times for donning and doffing during the 

break do not satisfy the obligation imposed by the statute and the regulation.” Id. at 13. 

It noted that “[t]he questions relevant to remedy may require a determination of the 

reasonableness of the plug times based on the 2007 measurements,” and “[a]n appropriate 

remedy for the failure to provide a bon[a] fide 30 minute meal break must be 

determined.” Id. at 13–14. 

During the second phase of the bench trial, the court considered the parties’ expert 

testimony and reports on the reasonableness of the plug times paid to employees. 

Plaintiffs presented the opinions of Dr. Robert G. Radwin to support their position that 

the plug times did not reasonably compensate them. He relied primarily on videos of 

plant operations that included two full daily shifts. To obtain his time measurements, he 

used a video-analysis software program to calculate the time that employees actually 
12 

spent on various activities. Comparing his measurements to the pre-2010 plug times, Dr. 

Radwin concluded that JBS owed Plaintiffs from 1.7 to 14.6 minutes per day beyond the 

plug times for work on different shifts on different production lines. 

JBS countered with the testimony and report of Dr. Paul S. Adams. Dr. Adams 

relied on the same videos and evidence as Dr. Radwin, but he used a different method to 

calculate the times. He broke the relevant activities into elements that corresponded to 

articles—that is, single items of clothing or personal equipment. The element times were 

then added to develop estimates for the full set of articles worn by various workers. He 

excluded avoidable delays, such as personal phone use or socializing. Ultimately, his 

walk times were very similar to the walk times JBS began paying in 2010. For instance, 

he concluded that the pre- and post-shift walk time for slaughter employees was 1.46 

minutes, compared to the plug time of 1.43 minutes, and that pre- and post-shift walk 

time for fabrication employees was 3.25 minutes, compared to the 3.21-minute plug time. 

Some of his remaining measurements were greater than the plug times under the 

collective-bargaining agreements, and some were less; but overall his times were slightly 

longer. 

Dr. Adams also challenged Dr. Radwin’s videos (and, implicitly, Dr. Adams’s 

own calculations based on that evidence). He noted that “[t]he video[s] . . . were 

apparently taken for demonstrative purposes and were not taken to facilitate time study”; 

“[t]he poor camera angles and lines of sight in the supplied videos prevented the proper 

capture of many beginning and ending points”; “[t]he obtrusive camera crew was 

obviously noticed by many subjects and their behaviors were affected”; and “[m]any 
13 

activity areas were not included in the videos.” Id. at 1883–84 (Report of Dr. Adams at 

7–8). One consequence was that there were “insufficient sample sizes for a scientific 

study.” Id. at 1884. In addition, Dr. Adams expressed numerous criticisms of Dr. 

Radwin’s use of the videos. He complained that Dr. Radwin measured the time 

employees chose to take to complete an activity rather than the time the employee was 

actively engaged in the activity; did not follow established scientific methodology for 

time studies; failed to account for differences among workers in what personal protective 

equipment they wore; failed to account for workers who did not wait in line; assigned 

times to employees who did not actually perform the activity assigned; and used a walktime methodology that “resulted in double counting and inflated values due to improper 

geographical weighting of calculated times.” Id. at 1893 (Report of Dr. Adams at 17).

After considering the expert testimony and reports, the district court rejected Dr. 

Radwin’s opinions and concluded that Plaintiffs had failed to meet their burden of 

proving that the plug times did not reasonably compensate them for work time not 

included in the gang time. The district court also rejected Plaintiffs’ claim that the entire 

meal period was compensable. It said that it had incorrectly assumed in its first order that 

a 30-minute meal break was required under the FLSA. On reconsideration, it concluded 

that the predominant benefit of the meal break was for the employees because the 

“predominant purpose of the 30 minute break is to provide an opportunity to eat and the 

company provides cafeteria services for that purpose.” Aplt. Add. at 20 (Final Order – 

Doc. 231). To the extent that Plaintiffs were entitled to compensation for work 

performed during the meal break, it ruled that they had not shown that the work time 
14 

exceeded the plug time they had been accorded in the collective-bargaining agreement. 

The court entered judgment in favor of JBS and dismissed the case. 

Plaintiffs’ briefs are not clear about what specific relief they are seeking on appeal. 

As best we can understand: (1) they are seeking walk time before and after their 

production-line shifts to the extent it has not been properly compensated by plug times 

paid by JBS; and (2) although they are no longer contending that the meal break is not a 

bona fide meal period, they do seek payment for the time during their break engaged in 

walking, washing, donning, and doffing not properly compensated by plug times. We 

reject Plaintiffs’ arguments. We therefore need not address JBS’s alternative grounds for 

affirmance—that it acted in good faith (which can excuse noncompliance with the FLSA, 

see 29 U.S.C. § 259), and that Plaintiffs failed to present testimony representative of all 

the various types of employees included as Plaintiffs, see Reich v. S. Md. Hosp., 43 F.3d 

949, 951–52 (4th Cir. 1995). We note, however, that those alternative grounds for 

affirmance were not properly raised as a cross-appeal; an answer brief is the proper 

vehicle to raise arguments that do not seek greater relief than that afforded by the districtcourt judgment. See Jennings v. Stephens, 135 S. Ct. 793, 798 (2015); United States v. 

Madrid, 633 F.3d 1222, 1225 (10th Cir. 2011) (“The office of a cross-appeal is to give 

the appellee more than it obtained by the lower-court judgment.”) 

II. ANALYSIS 

“When a party appeals from a bench trial, we review the district court’s factual 

findings for clear error and its legal conclusions de novo.” Gallardo v. United States, 

752 F.3d 865, 870 (10th Cir. 2014). “If the district court’s account of the evidence is 
15 

plausible in light of the record viewed in its entirety, [we] may not reverse it even though 

convinced that had [we] been sitting as the trier of fact, [we] would have weighed the 

evidence differently.” Anderson v. City of Bessemer City, N.C., 470 U.S. 564, 573–74 

(1985). 

A. Issues Decided Summarily 

We begin by quickly disposing of several of Plaintiffs’ arguments on appeal. 

First, they complain that the district court did not impose the relief required by its initial 

decision after the liability stage of the trial. But that decision did not bind the court. It 

was an interlocutory decision, which the court could revise at any time before final 

judgment. See Rimbert v. Eli Lilly and Co., 647 F.3d 1247, 1251 (10th Cir. 2011). The 

court recognized that it had changed its mind on some matters. The opinion after the 

second stage of trial states: “It must be admitted that the result now reached is contrary 

to the expectations generated by the previous Order. It is, however, the result of careful 

reflection on the evidence in this case and the court opinions cited above.” Final Order at 

10. We review only that second opinion, not the one superseded by it. 

Second, Plaintiffs complain that the district court’s findings of fact and 

conclusions of law do not satisfy Fed. R. Civ. P. 52(a), which governs findings and 

conclusions. But a court’s findings and conclusions are satisfactory if they enable the 

appellate court to conduct a proper review of the decision below. See OCI Wyo., L.P. v. 

PacifiCorp, 479 F.3d 1199, 1203–04 (10th Cir. 2007). Plaintiffs’ brief fails to explain 

how the findings or conclusions in this case fall short on a material issue. Indeed, the 

argument on this point in their opening brief is so vague and general that we could 
16 

properly rule that the issue is waived. See Baca v. Berry, 806 F.3d 1262, 1276 (10th Cir. 

2015). In any event, the district court’s findings and conclusions are adequate for our 

review. 

Third, Plaintiffs argue that the district court improperly found that JBS could 

avoid liquidated damages because it acted in good faith. But that issue is moot because 

we affirm the decision that JBS did not violate the law in the first place. 

That leaves two issues to resolve: the adequacy of compensation (1) for walk 

times before and after the employee is engaged on a production line and (2) for meal 

breaks. 

B. Walk Time at Beginning and End of Shift 

In district court Plaintiffs challenged the adequacy of the plug times paid by JBS 

for walk time by employees between the locker rooms and the production floors at both 

ends of their shifts. The district court rejected the challenge because it refused to credit 

the findings by Dr. Radwin, Plaintiffs’ expert on that matter. The court’s rejection was 

based largely on the opinion of Dr. Adams, the JBS expert. See Final Order at 8 (“On 

balance, this Court accepts the opinions of Dr. Adams.”). Dr. Adams expressed the view 

that even using Dr. Radwin’s questionable data, the plug times were reasonably close to, 

and sometimes greater than, the times necessary to perform the various activities. The 

court concluded that Dr. Radwin’s calculations did “not adequately account for all of the 

variations involved” in the time it takes different employees to perform the same activity. 

Id. at 21. It noted that “Dr. Radwin’s calculations are based on very limited 

information.” Id. And it said: “[Dr. Adams’s] results are markedly different from those 
17 

of Dr. Radwin. These differences reflect the underlying difficulty in attempting to 

determine the realities of the workplace by those methods.” Id. at 8. In our view, the 

court’s rejection of Dr. Radwin’s plug times was reasonable; and we note that on appeal 

Plaintiffs do not contest the rejection. 

That leaves the argument raised by Plaintiffs on appeal, which relies on JBS’s 

adoption of the plug times included in the 2010 collective-bargaining agreement for walk 

time from the locker room to the production floors before the workers’ shifts and for 

walk time from the wash area to the locker room after the shifts. They argue that JBS 

essentially conceded in that agreement that those plug times are necessary to comply with 

the FLSA. They therefore claim that under their complaint filed in 2008 they can recover 

this unpaid work time beginning in 2006 (or 2005 if JBS’s violation of its duty to pay 

was willful, see 29 U.S.C. § 255(a)). Some workers have already been paid part of what 

Plaintiffs claim because in 2010 JBS agreed with the Union that the additional plug times 

would be paid to current employees for work in 2008 and thereafter (but would not be 

paid to those no longer employed by JBS in 2010). As a result, Plaintiffs contend that 

they all are entitled to back pay beginning in 2006 (or 2005), although those working in 

2010 would not receive backpay for work after 2007. The district court refused to order 

payment for those times because Plaintiffs failed to produce credible supporting evidence 

of the walk times. 

We affirm, but on an alternative ground raised by JBS. We hold that walk times 

from the locker rooms to the production floors at the beginning of the shift and from the 

wash stands to the locker rooms at the end of the shift were not compensable work before 
18 

plug times were added for that activity in the 2010 collective-bargaining agreement 

between the Union and JBS. Our analysis is as follows: First, under § 203(o), time at the 

beginning or end of the workday devoted to changing clothes is not compensable if so 

determined under a collective-bargaining agreement. Second, the Supreme Court has 

ruled that time spent donning or doffing items that cannot be described as clothing is also 

noncompensable under § 203(o) if performed at the same time as the noncompensable 

changing of clothes and the period “can, on the whole, be fairly characterized as time 

spent in changing clothes . . . .” Sandifer v. U.S. Steel Corp., 134 S. Ct. 870, 881 (2014) 

(internal quotation marks omitted). In particular, the time would still be noncompensable 

even if workers spend a comparatively small part of the time gathering or disposing of 

equipment. Third, agreeing with Sandifer v. U.S. Steel Corp., 678 F.3d 590, 595–98 (7th 

Cir. 2012), we hold that if time to perform an activity is noncompensable under § 203(o), 

then the activity is not a “principal activity” that begins or ends the workday. Therefore, 

walk time between the production floor and the locker room, where noncompensable 

donning or doffing occurs, is noncompensable under the Portal–to Portal Act. Fourth, 

agreeing with then-Judge Sotomayor’s opinion in Singh v. City of New York, 524 F.3d 

361, 367–70 (2d Cir. 2008), we hold that travel to the place where the employee performs 

a principal activity of the job, which is ordinarily noncompensable under the Portal-toPortal Act, does not become compensable just because during that travel the employee 

must carry an item necessary for performance of the work if carrying the item adds 

negligible time or inconvenience to the travel. Therefore, walk time between the 

production floor and the locker room is noncompensable even if an employee must carry 
19 

equipment on the way. Fifth and finally, because the purpose of § 203(o) is to leave 

compensability of certain activities to collective bargaining, see Sandifer, 134 S. Ct. at 

876, it follows that if collective bargaining results in providing some compensation for 

unmeasured work time, such compensation does not convert any additional otherwisenoncompensable activities into work time. Therefore, walk time after donning and before 

doffing that would otherwise be noncompensable does not become compensable just 

because the collective-bargaining agreement provides plug time for some donning or 

doffing. We proceed to explain more fully. 

 We begin with 29 U.S.C. § 203(o). Under that statute, “the compensability of 

time spent changing clothes or washing is a subject appropriately committed to collective 

bargaining.” Sandifer v. U.S. Steel Corp., 134 S. Ct. 870, 876 (2014). The statute 

renders those activities noncompensable if they are “excluded from measured working 

time during the week involved by the express terms of or by custom or practice under a 

bona fide collective-bargaining agreement.” 29 U.S.C. § 203(o)

1

; see Salazar v. 

Butterball, LLC, 644 F.3d 1130, 1135 (10th Cir. 2011). 

Moreover, a collective-bargaining agreement can also render noncompensable the 

donning and doffing of items that are not clothing as long as that donning and doffing 

adds relatively little time to the overall donning or doffing process. This was the holding 

 

1

 Section 203(o) states in full: “Hours Worked.--In determining for the purposes of 

sections 206 [Minimum wage] and 207 [Maximum hours] of this title the hours for 

which an employee is employed, there shall be excluded any time spent in changing 

clothes or washing at the beginning or end of each workday which was excluded 

from measured working time during the week involved by the express terms of or by 

custom or practice under a bona fide collective-bargaining agreement applicable to 

the particular employee.” 
20 

of Sandifer v. U.S. Steel Corp., 134 S. Ct. 870, 880–81 (2014). The Court did not reach 

its conclusion by applying the de minimis doctrine. It expressed doubt about the de 

minimis doctrine in the § 203(o) context, stating that it “does not fit comfortably within 

the statute at issue here, which, it can fairly be said, is all about trifles—the relatively 

insignificant periods of time in which employees wash up and put on various items of 

clothing needed for their jobs.” But the analysis is rather similar to that under the 

doctrine. Sandifer concerned employees who sought backpay for their time spent 

donning and doffing 12 items of protective gear, which they argued were not clothing 

subject to § 203(o). The district court held that the items were all clothes but that even if 

three items (hardhats, glasses, and earplugs) were not, the time spent on them was de 

minimis. See id. at 874. The Supreme Court affirmed that conclusion, but under 

somewhat different reasoning. It agreed that the employees’ time spent donning and 

doffing nine of the items qualified as changing clothes under § 203(o). See id. at 879. 

And even though the remaining three items were not clothes under § 203(o), the Court 

reasoned that on the whole the time could be characterized as changing clothes under § 

203(o). See id. at 881 (“The question for courts is whether the period at issue can, on the 

whole, be fairly characterized as time spent in changing clothes or washing.” (internal 

quotation marks omitted)). “If an employee devotes the vast majority of the time in 

question to putting on and off equipment or other non-clothes items . . . the entire period 

would not qualify as time spent in changing clothes under § 203(o), even if some clothes 

items were donned and doffed as well.” Id. “But if the vast majority of the time is spent 
21 

in donning and doffing clothes . . . , the entire period qualifies, and the time spent putting 

on and off other items need not be subtracted.” Id. 

It is unclear to us when the results under the de minimis doctrine and the on-thewhole test would differ. Perhaps the distinction is that compensation is required for 

activities that take only a short period of time if that period is nevertheless comparable to 

the time it takes to change clothes; in other words, the test is whether the time is 

relatively short, rather than whether it is short on some absolute scale. 

Sandifer seems applicable here. JBS and the Union have negotiated over the years 

whether compensation (through plug times) should be provided for activities before the 

worker arrives at the production line or after the worker departs the production line. Two 

of those activities are donning and doffing clothing and equipment in the locker room. 

We agree with Plaintiffs that not everything they don and doff can be described as 

clothing. But as we understand the district court’s findings at the end of the trial, the 

additional time for donning and doffing such nonclothing items is de minimis. Plaintiffs 

do not challenge that finding and any challenge would be unsuccessful in any event 

because the finding is a reasonable view (perhaps the only reasonable view) of the 

evidence. We conclude that the collective-bargaining agreement could therefore exclude 

the locker-room activities from compensation under § 203(o) because under Sandifer, 

134 S. Ct. at 881, the locker-room time was devoted “on the whole” to changing clothes. 

 One could nevertheless argue, however, that even though picking up (or returning) 

equipment and donning (or doffing) nonclothing items in the locker room are not 

compensable, those activities are still “principal activities” that start (and end) the 
22 

workday, so the walk times between the locker room and the production floor are 

compensable. (Recall that under the Portal-to-Portal Act, travel time is not compensated 

only if it precedes the first principal activity of the day or follows the last such activity. 

See 29 U.S.C. § 254(a).) We reject the argument. Facing the same issue, the Seventh 

Circuit explained in Sandifer: 

If [clothes-changing time] is not work time—the workers aren’t being paid 

and their union has agreed to their not being paid—how can it be one of the 

‘principal activities which the employee is employed to perform’? He is 

required to wear work clothes, and for that matter he is required to show up 

for work. But he is not employed to show up or employed to change 

clothes. Not all requirements imposed on employees constitute 

employment. An employee may be required to call in when he is sick, but 

unless he is on paid sick leave he is not paid for the time it takes to place 

the call. 

678 F.3d at 596 (internal ellipsis omitted). The court recognized that the Supreme Court 

had held in Alvarez, 546 U.S. at 37, that absent a collective-bargaining agreement on the 

matter, donning and doffing of work clothes at the workplace could be principal activities 

and walking between the locker room (where the donning and doffing occur) and the 

work station is not exempted from compensability by the Portal-to-Portal Act. But, said 

the court: 

Section 203(o) permits the parties to a collective bargaining agreement to 

reclassify changing time as nonworking time, and they did so, agreeing that 

the workday would not start when the workers changed their clothes; it 

would start when they arrived at their work site. If clothes-changing time is 

lawfully not compensated, we can’t see how it could be thought a principal 

employment activity, and so [the Portal-to-Portal Act] exempts the travel 

time in this case. 
23 

Sandifer, 678 F.3d at 596–97. The Eighth Circuit was persuaded, see Adair v. ConAGRA 

Foods, 728 F.3d 849, 852–53 (8th Cir. 2013), and so are we. But see Franklin v. 

Kellogg, 619 F.3d 604, 619 (6th Cir. 2010). After all, in enacting § 203(o), 

Congress was trying to eliminate the disruptions that the [Supreme] Court’s 

interpretation of the Fair Labor Standards Act had caused, and to allow the 

determination of what is compensable work in borderline cases (is changing 

into work clothes ‘work’? is walking from a locker room to a work station 

‘work’?) to be settled by negotiation between labor and management. 

 

Sandifer, 678 F.3d at 597–98; see also id. at 598 (quoting preamble to the Portalto-Portal Act in support). 

 What about the fact that Plaintiffs carried their tools of the trade (knives or hooks) 

between the locker room and the production floors? The travel from the locker room to 

the production floor (and back) is excluded from FLSA coverage by the Portal-to-Portal 

Act unless it follows (or precedes) a principal activity; and we have just held that 

Plaintiffs’ locker-room activities are excluded from being principal activities by § 203(o) 

and the parties’ collective-bargaining agreement. We do not believe that Plaintiffs’ 

carrying knives or hooks converts what would otherwise be noncompensable walk time 

into compensable walk time. The decision closest in point is the Second Circuit opinion 

in Singh, written by then-Judge Sotomayor. The plaintiffs in Singh, city fire-alarm 

inspectors, argued that they were entitled to compensation for all or part of their time 

spent commuting to and from work because their employer required that they “carry and 

keep safe necessary inspection documents during their commutes.” Singh, 524 F.3d 

at 364. The Second Circuit rejected their argument. Relying on the Supreme Court’s 

holding that whether time is work time depends on whether the “time is spent 
24 

predominantly for the employer’s benefit or for the employee’s,” Armour & Co. v. 

Wantok, 323 U.S. 126, 133 (1944), the court held that the predominant benefit of the 

commute was for the employees, not the employer: “Carrying a briefcase during a 

commute presents only a minimal burden on the inspectors, permitting them freely to use 

their commuting time as they otherwise would have without the briefcase. . . . While the 

city certainly benefits from the plaintiffs’ carrying these materials, it cannot be said that 

the City is the predominant beneficiary of this time.” Singh, 524 F.3d at 368–69. The 

court concluded that “the mere carrying of inspection documents does not transform 

plaintiffs’ otherwise non-compensable commute into compensable time.” Id. at 369. It 

added that its analysis “in many ways resembles a de minimis test.” Id. It cited the Sixth 

Circuit opinion in Aiken v. City of Memphis, 190 F.3d 753, 759 (6th Cir. 1999), which 

held that police officers need not be compensated for their commuting time even though 

they must monitor their police radios during this travel, “because ‘the amount of work 

involved in monitoring a police radio during a commute is simply de minimis.’” Singh, 

524 F.3d at 369 (quoting Aiken, 190 F.3d at 759). Then-Judge Sotomayor concluded, 

“The point is that, under either approach, when an employee is minimally restricted by an 

employer during a commute, such that his or her use of commuting time is materially 

unaltered, the commuting time will generally not be compensable under the FLSA.” Id.

In the case before us, there is no reason to believe that carrying equipment 

increased the walk time to any extent or meaningfully restricted what workers did on 

their way to the production floor. In fact, the district court noted that “employees are not 

required to move directly from their lockers to the line ... [or] to their lockers after 
25 

leaving the wash area at the end of the shift.” First Order at 10–11. (Stopping to wash 

the equipment on the way to the production floor would delay the trip but Plaintiffs are 

not challenging on appeal any failure to compensate for the wash time, which apparently 

is represented in the plug times.) Under the Singh analysis, the walk time in this case 

would not be compensable just because the worker is carrying a knife or hook. 

 There is one more possible wrinkle in this case. If the collective-bargaining 

agreement had totally eliminated compensation to employees for any of the walk time or 

clothes-changing time, the above analysis would compel the conclusion that the 

employees are not owed any additional compensation under the FLSA. But the 

agreement did provide plug times to compensate for clothes-changing time. We therefore 

may not be able to apply literally the holding in the Seventh Circuit opinion in Sandifer

that noncompensable work activity cannot be “principal activity” that marks the 

beginning or end of the workday. See 678 F.3d at 596–97.2

 Nevertheless, the 

proposition on which the reasoning in Sandifer was founded is that § 203(o) was enacted 

to leave to collective bargaining whether certain activities at the beginning and end of the 

workday off the production line should be compensated. It would make no sense to leave 

to collective bargaining whether there should be compensation for such activities but not 

 

2

 Section 203(o) excludes from employment hours the time “excluded from measured 

working time” by the collective-bargaining agreement. We assume, without 

deciding, that plug times are “measured working time” that has been adopted, not 

excluded, by the collective-bargaining agreement, even though they are not measured

during the work day (the plug time added to the worker’s time is based on one-time 

calculations incorporated in the collective-bargaining agreement). If plug times are 

not considered “measured working time,” however, then the activity covered by plug 

times is “excluded from measured working time,” and this case is identical to 

Sandifer in this respect. 
26 

how such activities are to be compensated. What possible policy rationale would require 

the negotiating parties to be limited to an all-or-nothing regime—either providing for no 

compensation for the activities or fully compensating all of them? We therefore give 

§ 203(o) the commonsense reading that it leaves to collective bargaining the extent to 

which employees will be compensated for activities that could be rendered totally 

noncompensable through that provision. 

 Applying this analysis to Plaintiffs’ claims, we conclude that (1) all the walk time 

for which they seek back pay could have been rendered noncompensable by the 

collective-bargaining agreement (through § 203(o)), and (2) therefore they were entitled 

only to compensation for walk time provided through the plug times in the collectivebargaining agreements in effect during the time at issue. We affirm the district court’s 

denial of the walk-time claims because Plaintiffs are seeking greater compensation than 

provided in the collective-bargaining agreements. 

C. Meal Break 

Plaintiffs’ final issue requires less discussion. They claim that they have been 

inadequately compensated for time spent donning, doffing, cleaning, and walking during 

their 30-minute meal break. Under 29 C.F.R. § 785.19(a), bona fide meal periods are not 

considered work time and are not compensable. A bona fide meal period is “[o]rdinarily 

30 minutes,” but “[a] shorter period may be long enough under special conditions.” Id. 

For a break to qualify as a bona fide meal period, “[t]he employee must be completely 

relieved from duty for the purposes of eating regular meals,” and “[t]he employee is not 
27 

relieved if he is required to perform any duties, whether active or inactive, while eating.” 

Id. 

Most courts, however, apply the predominant-benefit test to determine whether a 

meal period is bona fide. See, e.g., Reich v. S. New Eng. Telecomms. Corp., 121 F.3d 58, 

65 (2d Cir. 1997) (The “predominant benefit standard sensibly integrates developing case 

law with the regulations’ language and purpose, and more importantly, with the language 

of the FLSA itself.” (citation and internal quotation marks omitted)); Babcock v. Butler 

Cty., 806 F.3d 153, 156 (3d Cir. 2015); Roy v. Cty. of Lexington, S.C., 141 F.3d 533, 545 

(4th Cir. 1998); Hartsell v. Dr. Pepper Bottling Co. of Tex., 207 F.3d 269, 274 (5th Cir. 

2000); Ruffin v. MotorCity Casino, 775 F.3d 807, 811 (6th Cir. 2015); Leahy v. City of 

Chi., Ill., 96 F.3d 228, 230 n.2 (7th Cir. 1996); Guyton v. Tyson Foods, Inc., 767 F.3d 

754, 763 (8th Cir. 2014); Beasley v. Hillcrest Med. Ctr., 78 F. App’x 67, 69–70 (10th Cir. 

2003). But see Brennan v. Elmer’s Disposal Serv., Inc., 510 F.2d 84, 88 (9th Cir. 1975) 

(applying a completely-relieved-from-duty test under which “[a]n employee cannot be 

docked for lunch breaks during which he is required to continue with any duties related to 

his work” (emphasis added)). “The predominant benefit test[ ] asks whether the 

[employee] is primarily engaged in work-related duties during meal periods.” Babcock, 

806 F.3d at 156 (internal quotation marks omitted). If so, the employer must compensate 

the employee for the entire meal period. See Ruffin, 775 F.3d at 811. “But as long as the 

employee can pursue his or her mealtime adequately and comfortably, is not engaged in 

the performance of any substantial duties, and does not spend time predominantly for the 
28 

employer’s benefit, the employee is relieved of duty and is not entitled to compensation 

under the FLSA.” Id. (internal quotation marks omitted). 

On appeal, Plaintiffs do not contest that their meal break was a bona fide meal 

break. They challenge only the failure of the district court to compensate them for what 

they claim to be work performed during the break—donning, doffing, and walking. They 

contend that the district court denied compensation for the contested time on the ground 

that the predominant purpose of the meal break was to benefit the employees. If the court 

had rejected compensation on that ground, Plaintiffs might have a convincing argument. 

But that is not how we read the court’s decision. It discussed the predominant-benefit 

test only to resolve whether the meal break was a bona fide meal break. That discussion 

was necessary because Plaintiffs had argued (or at least the court thought that they had 

argued) that the break was not bona fide so Plaintiffs were entitled to compensation for 

all 30 minutes. After finding the meal break to be bona fide, the court examined whether 

the plug times for the meal break were adequate to compensate for work time during the 

break. It found that Plaintiffs had not met their burden of showing that the plug times for 

that period were inadequate. Plaintiffs have not challenged that ruling. And they would 

fail if they did. 

III. CONCLUSION 

For the foregoing reasons, we AFFIRM the district court’s judgment.