U.S. Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health
Page 2 Health Hazard Evaluation Report 2011-0131-3221

Contents

Highlights...............................................i

Abbreviations ..................................... iii

Introduction......................................... 1

Methods ............................................... 1

Results and Discussion........................ 3

Conclusions........................................ 17

Recommendations............................. 17

Appendix A ........................................ 22

References.......................................... 26

Acknowledgements........................... 31

The employer is required to post a copy of this report for 30 days at or near the 

workplace(s) of affected employees. The employer must take steps to ensure 

that the posted report is not altered, defaced, or covered by other material.

The cover photo is a close-up image of sorbent tubes, which are used by the HHE 

Program to measure airborne exposures. This photo is an artistic representation that may 

not be related to this Health Hazard Evaluation. Photo by NIOSH.
Health Hazard Evaluation Report 2011-0131-3221 Page i

We evaluated ergonomic, 

environmental temperature, 

and job stress concerns 

among employees at an airline 

catering facility. Employees 

used awkward postures and 

repetitive motions, stayed 

inside cold rooms for their 

entire shift, and experienced 

time pressure. We recommend 

redesigning workstations, 

rotating employees out of the 

cold rooms for part of their shift, 

and increasing teamwork and 

social support.

Highlights of this Evaluation

The Health Hazard Evaluation Program received a request from a union to evaluate an 

airline catering facility. The union was concerned about ergonomic risk factors, heat and cold 

exposure, and job stress. We evaluated the facility in September 2012.

What We Did

● We measured workstation heights and reach distances. We used this information and 

observations to determine work-related musculoskeletal disorder risk.

● We looked at logs of work-related injuries and illnesses.

● We measured air temperature and air flow inside 

cold rooms.

● We measured carbon monoxide at loading docks.

● We interviewed employees about their work, 

medical history, symptoms, job stress, personal 

protective equipment, and health and safety 

concerns.

What We Found

● Some employees used awkward postures and 

repetitive motions while doing their jobs. These 

factors increased their risk for work-related 

musculoskeletal disorders of the shoulders, 

back, and arms.

● The most common injuries reported on the logs 

were musculoskeletal strain, sprain, or pain.

● Employees reported diesel exhaust entering the 

loading docks during winter days.

● Employees reported health concerns from hot and cold temperatures.

● No confined space entry procedures were in place for cleaning the autoclave.

● Employees reported time pressure, high workload, lack of social support, and limited 

access to resources as common sources of job stress.

What the Employer Can Do

● Develop a written autoclave cleaning procedure. Follow guidelines and standards for 

confined space, lockout/tagout, and personal protective equipment.

● Design work areas to have a working height of 27–62 inches. 

● Provide work tables that have adjustable heights. 
Page ii

● Rotate employees to different job tasks after every break.

● Present all information such as training, messages to employees, and hazard 

communication materials in a manner that employees can understand. This may include 

languages other than English.

● Train employees on the health effects of exposure to hot and cold temperatures and 

ways to be more comfortable at work.

● Provide glove alternatives for employees inside cold rooms.

● Provide warm water or dry air heaters outside of the cold rooms for the employees to 

warm up their hands.

● Install horizontal baffle deflectors on all refrigerator fans located near workstations 

inside the cold rooms.

● Develop and implement a heat stress prevention program. Establish mandatory breaks 

for employees exposed to heat, including drivers.

● Ensure new trucks have air conditioning.

● Perform preventative maintenance and repair trucks promptly if heating systems are 

not working.

● Seal loading docks so diesel truck exhaust does not enter the building.

● Educate employees on musculoskeletal disorders and ergonomics.

● Explore and address issues of job stress.

What Employees Can Do

● Keep heavy loads close to your body when lifting and carrying.

● Do not wear wet clothes inside the cold room.

● Drink plenty of fluids when exposed to heat.

● Take regular breaks to recover from extreme temperatures.

● Take part in safety and ergonomic committees.

● Report symptoms and injuries to supervisors and medical staff as soon as they occur.
Page iii

Abbreviations

ACGIH® American Conference of Governmental Industrial Hygienists

CFR Code of Federal Regulations

MSD Musculoskeletal disorder

NIOSH National Institute for Occupational Safety and Health

OEL Occupational exposure limit

OSHA Occupational Safety and Health Administration

PPE Personal protective equipment

SOP Standard operating procedure

TLV® Threshold limit value

WBGT Wet bulb globe temperature
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Page 1

Introduction

The Health Hazard Evaluation Program received a request from a union representing airline 

catering employees. The union was concerned about musculoskeletal disorders (MSDs), 

extreme hot and cold temperatures, job stress, and employees being injured while working 

in the kitchen and loading docks. In September 2011, we evaluated a facility in Michigan. 

We provided an interim letter detailing our evaluation and preliminary recommendations 

in November 2012. In January 2013, we evaluated a second facility in New York with 

employees represented by the same union. The concerns at the second facility were similar 

to those at the first. Additionally, concerns were raised about language barriers because 

most employees spoke a primary language other than English. This report covers the 2011 

evaluation of the Michigan facility. The results from the evaluation at the New York facility 

will be reported separately.

At the time of our September 2011 visit to the Michigan facility, production took place in 

a 213,000-square foot building that was constructed in 1981 and renovated in 1991. The 

facility had approximately 500 employees and operated two shifts. The company catered for 

one major airline at the airport and serviced 16 international flights and 220–260 domestic 

flights per day. Employees prepared food, beverages, and nonfood amenities (e.g., napkins, 

sugar packets, and stir sticks) and placed them in drawers. The drawer content varied by 

aircraft type and capacity. The drawers were then placed on food service carts. The carts were 

loaded onto trucks and delivered to the plane. Employees typically worked 8-hour shifts with 

a 30-minute lunch break and an additional 20-minute break. This work schedule covered 

most employees except drivers whose breaks varied depending on delivery schedules. 

Occasionally, employees worked voluntary overtime.

Methods

Ergonomics

We observed workplace conditions, processes, and practices. We measured workstation 

heights and reach distances and noted the availability of antifatigue mats and personal 

protective equipment (PPE). A full description of the criteria we used to determine risk 

factors for work-related MSDs is provided in Appendix A. We reviewed a report prepared by 

the company’s insurance provider in 2009 on their evaluation of musculoskeletal risk factors 

for employees pushing airline service carts. We reviewed training materials and standard 

operating procedures (SOPs) provided to employees upon hire. 

Cold Exposure

We evaluated cold exposures by sampling two cold rooms where employees routinely 

worked for varying periods throughout the day (3 to 8 hours per 8-hour shift). We collected 

information on factors that can influence an employee’s response to cold, including air 

temperature, air velocity, humidity, physical activity, work/rest schedule, and type of 

protective clothing worn [Canadian Centre for Occupational Health and Safety 2008]. We 

measured temperature and relative humidity with a HOBO H08-032-IS Pro Series Relative 
Page 2

Humidity/Temperature Data Logger. The temperature and relative humidity measurements 

were taken simultaneously in different locations within the cold rooms to determine 

variability. We estimated air velocities inside the cold rooms with a TSI VelociCalc® Plus 

with articulated arm (model 8386A). Air velocities were measured at a typical standing chest 

height to capture what employees were experiencing at their workstations. We reviewed the 

company’s daily temperature records for the cold room, and obtained temperature records for 

one summer month and one winter month for each of the past 2 years. This information was 

compared to available guidelines for working in cold environments [ACGIH 2014]. 

Heat Stress

We evaluated hot environmental conditions in the autoclave and hot food area by measuring 

temperature and wet bulb globe temperature (WBGT) with a QUESTemp°36 instrument. In 

the autoclave area, we placed the WBGT monitor on the autoclave controls near the operator. 

In the hot food area, we placed the monitor by one of the cutting workstations near the ovens. 

The WBGT data from the hot food area was not used because of instrument failure during 

sampling. Metabolic rates were estimated on the basis of observation of work load by job 

task. The WBGT measurements and metabolic rate estimates were compared to the National 

Institute for Occupational Safety and Health (NIOSH) heat stress recommended exposure 

limit [NIOSH 1986] and the American Conference of Governmental Industrial Hygienists 

(ACGIH®) screening criteria [ACGIH 2014]. Food delivery trucks and flight line operations 

were not evaluated for heat stress because of mild environmental temperatures during our 

visit (approximately 75°F). 

Carbon Monoxide

We measured carbon monoxide concentrations in the loading and unloading docks with a 

BW Technologies direct-reading GasAlert Extreme meter to assess whether exhaust from 

diesel powered vehicles was entering the docks. After performing spot checks around the 

loading and unloading docks, we positioned the meters approximately 5 feet above the floor 

in several locations throughout the docks for the reminder of the workday. We talked to 

managers and employees about the operation of powered vehicles and any problems they 

may have encountered with exhaust from powered vehicles.

Employee Interviews and Document Review

Prior to our visit, we requested the following information: SOPs for different departments, an 

employee roster, and copies of the Occupational Safety and Health Administration (OSHA) 

Form 300 Log of Work-Related Injuries and Illnesses for years 2007–2011. We used the 

employee roster to select every third or fourth employee for an interview. This selection 

process continued until we believed we had a representative sample of the workplace 

population on the basis of sex, job title, length of employment with the company, and work 

shift. While on site, we held confidential, voluntary interviews with selected employees to 

discuss their workplace practices, medical history, job stress, psychosocial factors at work, 

and health and safety concerns. The interviews included scaled items (e.g., a job stress scale 

from Clark et al. 2011), open-ended questions, and forced choice (i.e., yes/no) response options. 
Page 3

Results and Discussion

Ergonomics

We observed employees in the assembly areas as they prepared liquor and beverage drawers, 

food drawers, nonfood amenities drawers, and first class snack trays. Assembly tables 

throughout the facility varied in height from 29ʺ–34ʺ. Each assembly area had shelves 

that contained bulk materials for stocking the drawers. These shelves varied in height 

from 26ʺ–67ʺ. The employee safety audit had documented that the soda assembly items 

were too high and awkward for the employee to reach, which was included in the audit 

item labeled, “Equipment/materials at workstation are at or below shoulder level. Heavier 

items kept lower.” We also documented several assembly workstations where the work 

required outstretched arms in an extended reach. These kinds of tasks place stress on the 

shoulders, elbows, and back when reaching. The food production SOP recommended an 

“efficient” work area, where the employee’s “work envelope” (the maximum overall area 

where the employee works) is reduced in size to increase overall efficiency by minimizing 

the employee’s movements. However, if the work envelope is reduced too much, then 

reconfiguring the work area may require shelves that are higher or lower than recommended 

to prevent musculoskeletal problems. Because the workstations are not adjustable, higher and 

lower shelving could cause extended reaches and awkward postures for some employees.

After learning that the “lean team” was responsible for designing workstations, we spoke 

with a lean team member who clarified that its purpose was to “optimize flow and decrease 

waste.” The lean team had designed workstations for the “average” employee, which 

is not recommended because it excludes approximately 67% of the working population 

[Humantech 2009].

After the trays were assembled they were placed on flow racks used by other employees to 

complete a cart. These flow racks varied in height from 26ʺ–66ʺ on the replenish side and 

24ʺ–60ʺ on the retrieval side.

Canned and bottled beverages were stored on pallets in another area of the facility. The 

pallets were stacked next to each other directly on the floor. Employees could access the 

pallets on only one or two sides, resulting in extended reaches and the need to lift materials 

from floor level to above shoulder level. This item had been noted on a recent employee 

safety audit as an area that needed improvement; the audit recommends that “boxes, cartons, 

and equipment stored on pallets are in orderly stacks and no higher than 60ʺ from the floor.” 

The lifting and moving water SOP included only water, not soda or other items stored on 

pallets. The SOP stated that “pallets should have access from all sides, and cases should not 

be stacked above waist level.” This procedure was not being followed with other palletized 

material, such as soda.

We observed employees in the food prep cold room preparing and packaging food for first 

class meals. The tables in the food prep cold room were 35ʺ in height and had a supporting 

shelf for materials that was 48ʺ in height. Some employees did not rotate to different 

job tasks and stood at the workstations all day without an antifatigue mat. Prolonged 
Page 4

standing had been documented on the recent employee safety audit as an area that needed 

improvement; the audit recommends that “antifatigue mats are used in work areas that 

employees must stand all day. Fatigue mats are in good condition and have beveled edges so 

as not to cause a tripping hazard and for ease of cart movement.”

We observed employees preparing “napkin roll-ups” by wrapping napkins around silverware 

and then securing the napkin with an adhesive sticker. Two employees were sitting while 

performing the task; a third employee alternated between sitting and standing. Each 

employee performed a different step in the process. Employees rotated between the three 

different tasks at their discretion. The table height was 36ʺ and the reach distances for the 

napkins, silverware, and stickers ranged from 13ʺ–18ʺ. The table height is within the range 

for both seated and standing workstations. Reach distances should be within 16ʺ and should 

not exceed 22ʺ.

We reviewed a 2009 report from the company’s insurance provider on their evaluation of 

employees pushing airline carts. We verified some of the cart push forces reported by the 

provider. We agreed with the insurance provider’s recommendation that employees push a 

maximum of four loaded carts strapped together or six empty carts strapped together. We also 

reviewed the dish room SOP and the cart pushing SOP. Although the company revised their 

procedures to reflect the insurance provider’s recommendation, both SOPs still contained the 

higher maximum number of carts (four loaded carts and ten empty carts). These documents 

should be modified to reflect the existing procedures. The cart pushing SOP was also missing 

a section addressing a schedule for inspection and maintenance of cart wheels and floor 

surfaces, both of which are important to prevent injuries when pushing carts. 

Assembly employees placed carts on the dock on the basis of plane type. The procedure, 

as we observed, seemed to cause confusion among the drivers and loaders, and carts were 

moved around the dock because employees had trouble finding the correct cart for the 

particular driver. Drivers and loaders placed carts onto trucks on the basis of flight departure times.

It is important to ensure that employees understand the potential hazards in the food service 

industry and how to protect themselves. Work-related MSDs comprise most of the injuries 

in food service industries [Cal/OSHA 2003]. Most injuries, according to the OSHA Logs 

we reviewed, were work-related MSDs. Engineering, work practice, and administrative 

improvements should be made to reduce risk factors for MSDs. In the short term, 

repositioning placement of items, such as cases of water, beer, and soda, could have a big 

impact on employee injury risk. Placement should eliminate reaching overhead, eliminate 

extreme bending of the back and twisting of the trunk, and reduce the amount of lifting of 

water, soda, and beer cases. 

The new hire orientation materials we reviewed had a suggestion for stretching exercises. 

We did not see any employees performing the stretches. Stretching exercise programs should 

be part of a comprehensive ergonomic program. The Washington State Department of Labor 

and Industries has an online guide with information on how to set up an ergonomic program 

[Washington State Department of Labor and Industries 2005]. 
Page 5

Cold Exposure

The facility had two cold rooms, “food prep” (where food was prepared for trays) and “cold 

food” (where full carts were stored before being loaded onto the plane). The cold food room 

was further divided into an international section and a domestic section that were separated 

by a door. The international section was approximately six times larger than the domestic section.

Both cold rooms were climate conditioned to approximately 40°F, a temperature required 

by food safety standards. The air temperature was maintained by roof-mounted refrigerator 

units (heat pumps) located around the upper perimeter of the rooms. No outdoor air was 

introduced into the cold rooms by the heat pumps. Each refrigerator unit had two to four fans 

and a temperature control unit with no visual display. Each cold room had a thermometer 

displaying the temperature inside the cold room. The temperature was also displayed outside 

the room. Air temperature was documented daily for both shifts and the thermometer was 

checked against a primary standard once a month for accuracy.

We estimated the activity level for most cold room employees as light to moderate, 

depending on the job tasks for the day. The company provided mandatory PPE to protect the 

food from contamination (e.g., lab coat, hairnet, plastic sleeve guards, plastic or polyvinyl 

chloride gloves, and apron) and optional PPE for warmth (e.g., coat, hat, and liner gloves). 

Employees also reported wearing additional personal clothing for comfort.

Some employees were concerned about drafts inside the cold rooms and believed that some 

areas were colder than others. Metal deflectors were installed on some of the refrigerator 

units several years ago because of employees’ concerns with drafts at their workstations. The 

deflector design (Figure 1) seemed to have decreased some of the drafts in the cold rooms but 

we noticed condensation from the cold air striking the metal deflector. The condensate water 

collected inside the deflector; creating the potential for microbial growth.

Figure 1. Fan refrigerator unit assembly with deflectors. Figure by NIOSH.
Page 6

The food prep cold room had food storage areas containing shelves, carts, and tables. The 

room had 12–16 workstations, three strip curtain doors, one solid door, and six refrigerator 

units with a total of 12 fans. Depending on the production demands, 7–25 employees worked 

in the room and the workstations varied depending on the type of task performed at each 

table. Some of these employees went in and out to retrieve supplies; therefore, they spent 4–6 

hours inside the cold room per shift. Food prep employees assembled meals individually or 

in teams of two or three.

Some of the assembled meals required fine motor skills (e.g., decorating with small 

garnishes, picking shrimp with toothpicks, cutting very thin slices of fish). Employees 

performing these tasks stated that they could only wear plastic gloves as additional layers 

would limit dexterity. In some instances, the food they were handling was frozen, and 

employees reported that their hands were cold and numb.

The cold room temperatures, relative humidity, and air velocities we measured are presented 

in Tables 1 and 2. The three food prep workstations we evaluated included two in opposite 

corners and a middle workstation near a door. The temperatures averaged 43.1°F. At any 

given time, the three workstations had a maximum temperature difference of +/−2°F.

Table 1. Temperatures and relative humidity measured inside cold rooms on September 21, 2011

Work area Sampling time %RH Temperature at workstations (°F)

#1 #2 #3 Average

Food prep 9:06 a.m.–5:04 p.m. 67–95 Average 41.6 43.8 43.9 43.1

Minimum 40.2 42.5 43.2

Maximum 43.9 45.4 46.8

International

cold food

9:06 a.m.–4:45 p.m. 59–89 Average 40.4 39.4 NS 40.8

Minimum 38.0 37.2 NS

Maximum 44.6 41.0 NS

NS = not sampled 

RH = relative humidity

In contrast, we measured a wide range of air velocities inside the food prep cold room. All 

job sites had room average air velocities below the ACGIH cold stress threshold limit value 

(TLV®) of 200 feet per minute for job sites inside refrigerated rooms [ACGIH 2014]. Cold 

room temperatures approached the 40°F lower operating limit of the air velocity instrument. 

It is possible that instrument limitations could have contributed to the fluctuations in the air 

velocity readings.
Page 7

Table 2. Air velocities measured inside cold rooms on September 21, 2011

Work area Shift Number of

samples

Air velocity*

(feet per minute average and range)

Food prep Day 7 59.3 (14–116)

Night 7 53.3 (24–105)

International cold food Day 6 146.3 (30–240)

Night 6 103.4 (25–259)

Domestic cold food Day 2 89.5 (70–109)

Night 2 33.8 (2–51)

*A range of air velocities was noted instead of a single value when the instrument displayed 

unstable readings due to turbulent flow conditions. We used the average of the minimum and 

maximum from several readings within the cold room to calculate the reported average. 

Table 3. Cold rooms air temperature records

Air temperature averages (°F)

Food prep* International† Domestic†

Month and year Day

shift

Night

shift

Day

shift

Night

shift

Day

shift

Night

shift

February 2010 40.6 40.7 40.8 40.3 40.0 40.2

February 2011 41.7 40.9 42.2 41.8 41.3 40.5

July 2010 40.8 40.9 40.5 38.1 37.5 36.9

August 2011 42.9 42.3 43.4 37.7 34.7 36.6

*Data from company records. Some temperature data (< 5%) were illegible and were not included 

in the data analysis. 

†Data from company records. Some temperature data (< 20%) were illegible and were not included 

in the data analysis.

We analyzed the company’s daily air temperature records for 2 months each in 2010 and 

2011 (Table 3). Air temperatures were fairly uniform between the months and work shifts 

and were similar to our September 2011 measurements (Table 1).
Page 8

International Cold Food

Up to three employees worked in the international cold food room. The room had food 

shelves and carts, two strip curtain doors, two solid doors, and eight refrigerator units with 

a total of 24 refrigerator fans. Four of the refrigerator fans did not have deflectors. We 

observed employees prepping food; job tasks required mobility and included stocking food 

and organizing or checking food carts. Employees remained inside the room for most of 

their shift (up to 6 hours) but in some instances left to transport carts. Temperatures around 

two workstations at opposite ends of the room averaged 40.8°F (Table 1). The maximum 

temperature variability between the two measurement locations at a given time was 5°F.

We analyzed the company’s daily temperature records from the international cold food room 

for 2 months each in 2010 and 2011 (Table 3). No difference was noted between the average 

recorded temperatures for the day and night shift. Temperatures were less variable in the 

international cold food room than in food prep cold room.

Air velocities measured during the day and night shifts in the international cold food room 

are listed in Table 2. The average air velocities, 146 feet per minute during the day shift 

and 103.4 feet per minute during the night shift, were below the cold stress ACGIH TLV 

of 200 feet per minute [ACGIH 2014]. However, some of the maximum air velocities in 

the international cold food room were above the guideline. The higher air velocities in the 

international cold food room could be due to the lack of deflectors on some of the refrigerator units.

Domestic Cold Food

The domestic cold food room had three solid doors and two refrigerator units with a total of 

six refrigerator fans. None of the refrigerator fans had deflectors. Employees only entered the 

domestic cold room briefly to leave carts in storage.

We analyzed the company’s daily temperature records for the domestic cold food room 

for 2 months each in 2010 and 2011 (Table 3). Temperatures were slightly more variable 

than in the food prep cold room (< 8% coefficient of variation for domestic cold food room 

compared to < 3.5% coefficient of variation for food prep, Table 3). Differences in the 

recorded temperatures for the day and night shift were minimal.

Air velocity measurements taken during the day and night shifts in the domestic cold room 

are listed in Table 2. The average air velocities, 89.5 feet per minute during the day shift and 

33.8 feet per minute during the night shift, were below the cold stress ACGIH TLV of 200 

feet per minute [ACGIH 2014]. 

The food prep cold room employees were exposed to cold temperatures and drafts from vents 

and fans blowing directly on them. Approximately 130 employees worked in the cold food 

department as food preparers at the time of our evaluation. Cold exposure has a negative 

impact on human performance, particularly for those with certain pre-existing medical 

conditions such as certain infectious diseases, cardiovascular and metabolic disorders, or 

musculoskeletal problems [Holmer et al. 1998]. A cold environment may also increase the 

chances of an injury or aggravate an existing injury [Cal/OSHA 2003]. Cold storage work 

is an artificial cold exposure that is characterized by a controlled climate. Employees can 
Page 9

preserve body heat, particularly in their hands, by wearing appropriate protective clothing 

such as thin cotton gloves worn underneath metal gloves when cutting meat. In many cool 

workplaces, preservation of manual dexterity poses challenges for the employees [Holmer et 

al. 1998]. Some cold room employees reported cold fingers and reported that putting on gloves 

reduced dexterity. The ACGIH recommends establishing special provisions to keep hands 

warm for employees doing fine work with bare hands for more than 10–20 minutes in an 

environment below 60.8°F [ACGIH 2014]. The company provided gloves and long insulated 

coats and allowed employees to wear hats but lacked a written cold room safety policy or SOP.

Heat Stress

Autoclave Operators

The highest air temperature measured in the autoclave area was 87.0°F (average 80.1°F), and 

the highest calculated indoor WBGT reading in the autoclave department was 79.4°F with an 

average of 74.8°F. The WBGT results indicate that most surfaces in the autoclave department 

were warm and served as radiant heat sources. 

The autoclave operators’ activities included pulling large carts of trash, loading and 

unloading the autoclave, operating the autoclave, moving trash, and cleaning the autoclave. 

We estimated the operators’ metabolic rate as moderate, defined as “sustained moderate hand 

and arm work, moderate arm and leg work, moderate arm and trunk work, or light pushing 

and pulling and normal walking” [ACGIH 2014]. No clothing adjustment factor [ACGIH 

2014] was needed because the employee was lightly clothed in an undershirt, short sleeve 

shirt, and pants. Leather protective gloves were worn for handling trash and working with hot 

surfaces. No safety glasses were worn.

We compared the WBGT results and metabolic rate estimates to those listed in the 

NIOSH recommended exposure limits to determine a work/rest schedule [NIOSH 1986]. 

The comparison yielded a recommendation of continuous work for employees when 

environmental conditions are similar to those on the day we evaluated.

We also compared our WBGT measurements and metabolic rate estimates to the ACGIH 

screening criteria [ACGIH 2014] to determine a work/rest schedule. These criteria suggest a 

continuous work schedule is acceptable for acclimatized employees with moderate workloads 

in environments with a WBGT between 77°F and 82.4°F. The maximum WBGT (79.4°F) 

we measured in the autoclave department was within this range, but was above the ACGIH 

action level (77°F) for a moderate workload and without a clothing factor adjustment 

[ACGIH 2014]. When WBGT values are above the action level, ACGIH recommends 

implementing precautionary general controls to avoid heat strain, especially in the summer 

months when outside temperatures are expected to rise significantly above those we 

measured. ACGIH recommends a heat stress management program including monitoring of 

the environmental temperature in the area of concern [ACGIH 2014].

The NIOSH recommended exposure limit and ACGIH TLV assume a 5-day workweek and 

an 8-hour workday with short morning and afternoon breaks (approximately 15 minutes 

each) and a longer lunch break (approximately 30 minutes). 
Page 10

Truck Drivers

Although we did not evaluate heat stress conditions in the food delivery trucks, we talked 

to several employees and management representatives about temperatures in the trucks. 

Employees reported that the trucks were poorly maintained (e.g., some trucks had no air 

conditioning or had windows that did not open or close). Employees reported that the heating 

system in some of the trucks could not be turned off so it operated throughout the year.

Managers reported that a typical delivery job took about 2 hours and included loading the 

truck at the dock, driving approximately 25 minutes to the airport, going through airport 

security, driving to the plane parked on the tarmac, unloading carts from the truck to the 

plane, and then driving back to the dock. The delivery could take longer if the plane was not 

ready to receive the carts. Employees were expected to do three or four deliveries during 

their shift. Employees could take a break between deliveries in an air conditioned room at 

the airline catering facility. However, managers said that on busy days employees sometimes 

skipped these breaks to keep up with job demands. Some employees also reported that they 

skipped breaks to shorten their shift so they could leave work early.

Drivers, loaders, and sanitation (i.e., autoclave operators, dishwashers) employees were 

potentially exposed to hot temperatures. Although conditions were cool during our visit, the 

potential exists for delivery truck drivers and the autoclave operator to work in hot conditions 

during the summer months. Heat measurements in the autoclave area suggest a continuous 

work schedule is acceptable for acclimatized employees with moderate workloads when 

outdoor temperatures are in the mid-70s. For the temperatures we measured in these work 

areas, acclimatization for most people occurs in 4 days by exposing them to progressively 

longer periods in a hot work environment [NIOSH 1986]. We reviewed the heat-related 

disorders training materials provided by the company. The training included sources of heat, 

symptoms of heat-related disorders, and recommendations for preventing heat stress, such 

as taking breaks in a cool area and drinking one glass of water every 20 minutes. However, 

breaks were limited to two per 8-hour shift, and beverages were prohibited in most work areas.

Carbon Monoxide

We did not detect carbon monoxide in the loading and unloading docks (limit of detection 

was 1 part per million), which together with field observations during our visit suggests 

that truck exhaust was negligible in these areas during our evaluation. However, employees 

reported diesel odors in the docks, especially in the winter months. Appendix A provides 

a brief description of occupational exposure limits (OELs) and provides specific health 

information about diesel exhaust and carbon monoxide.

Although the employer required delivery trucks to be turned off during loading and 

unloading, company policy required trucks to be left running at other times during the 

winter months to avoid difficult startups. During a typical winter day trucks were warmed 

up and kept idling for several hours in a parking lot adjacent to the loading and unloading 

docks. Depending on the prevailing wind direction, truck exhaust may enter the building. 

Employees mentioned that truck exhaust sometimes entered the building through the open 
Page 11

dock doors. Employees reported transient eye and throat irritation and headaches that were 

possibly associated with truck exhaust. Because of the transient irritation experienced by 

employees and the potential risk of cancer from occupational exposure to diesel exhaust 

emissions [NIOSH 1988; IARC 1989; Garshick et al. 2004; Attfield et al. 2012; Silverman 

et al. 2012] efforts to reduce exposure to truck emissions are needed. During our visit, the 

employer communicated to us plans to address truck exhaust concerns in the near future.

Other Observed Hazards

The autoclave operator cleaned the approximately 5 × 20 foot autoclave weekly. To remove 

debris, the employee had to physically enter into the autoclave after it cooled. The company 

had no written procedures for entering and cleaning the autoclave, and no lockout/tagout or 

confined space program. The autoclave operator usually worked alone, even when cleaning 

the autoclave.

Entering the autoclave without proper precautions regarding work in a hot environment 

or in an oxygen deficient atmosphere poses serious risks to employees. The water vapor 

used during autoclaving can displace oxygen inside the autoclave, possibly leading to 

asphyxiation. Entrapment is also a possible hazard. The autoclave might be considered a 

permit-required confined space on the basis of the OSHA confined space standard (29 CFR 

1910.146), because it had “limited entry and exit” through the 5-foot-wide door [OSHA 2007]. 

The company could best manage entry into the autoclave by following the OSHA standard 

for permit-required confined spaces (29 CFR 1910.146) [OSHA 2007] or the NIOSH 

recommendation to treat all confined spaces as permit-required confined spaces [NIOSH 

1979]. An autoclave operator, at a minimum, would need to follow lockout/tagout procedures 

and verify safe oxygen levels before entry. If the atmosphere was oxygen depleted (< 19.5% 

by volume), proper ventilation would be needed to eliminate the hazard. Alternatively, 

cleaning procedures could be developed that would not require the operator to enter, such as 

cleaning the autoclave from the outside with a large rake or high-pressure water.

Employee Interviews

We confidentially interviewed 55 of approximately 500 employees using a structured 

interview form. Of the 55 employees who completed interviews, 64% were male; the average 

age was 26 years (range: 20–62 years). Seventy-seven percent of interviewed employees 

spoke English as their primary language. Some interviews were not completed due to 

language barriers which prevented us from effectively communicating with the employee. 

Job titles included 23 liquor beverage assemblers, 11 cold room food preparation employees, 

11 drivers, 7 sanitation employees, and 3 others. Most interviewed employees reported 

working approximately 40 hours a week. About half of the participants responded that they 

rotated job tasks daily. The average time employed at the facility was 9 years (range: 1–23 years). 

Not all employees interviewed answered all questions. Thirteen of 55 employees (24%) 

reported having one or more health problems they believed were work-related. These 

included mostly musculoskeletal problems such as tendonitis, foot pain, arthritis, carpal 

tunnel syndrome, and back and shoulder pain. Thirty-two of 54 employees (59%) reported 
Page 12

discomfort with temperatures at work. Of these employees, 14 (44%) reported that extreme 

temperatures made them experience symptoms such as migraines, heat rash, fever, nausea, 

dizziness, lightheadedness, or other symptoms (e.g., sore throat, cough, runny nose) in the 

dishwashing area, on the dock, or in cold rooms. 

Employees were asked to respond “yes” or “no” to a question regarding injury or illness. 

Twenty-one of the 55 employees (38%) reported they had missed work, required treatment, 

or been reassigned to other duties because of an injury or illness. 

Health and Safety Concerns

We asked employees an open-ended question regarding what, if any, health and safety 

concerns they had about their job or how it was performed. Thirty-three of 55 employees 

(60%) reported health and safety concerns. The most frequently reported concerns were 

about injuries due to repetitive motions (n = 7), unsafe or unsanitary behaviors of coworkers 

(n = 5), truck maintenance issues (n = 5), and exposure to truck exhaust (n = 4). The 

remaining concerns were reported by three or fewer employees and are not listed.

Job Stress and Psychosocial Factors

NIOSH defines job stress as the harmful physical and emotional responses that occur when 

job demands do not match the capabilities, resources, or needs of employees [NIOSH 

2009]. We asked employees to rate their level of job stress over the past week on a scale from 

0 (as good as it can be) to 10 (as bad as it can be) [Clark et al. 2011]. Fifty-three employees 

answered this question, with the average response being 4.2. Figure 2 shows the distribution 

of responses to this question. Forty-nine percent of scores were between 0–3 (low job stress), 

19% were between 4–6 (moderate job stress), and 32% were between 7–10 (high job stress) 

[Clark et al. 2011].

Figure 2. Reported job stress level over the past week (N = 53).
Page 13

We asked employees an open-ended question regarding what, if any, stressors were present 

on the job. Forty (74%) employees reported one or more job stressors. Job stressors reported 

by five or more employees are listed in Table 4.

Table 4. Reported job stressors among employees (N = 54)

Job stressor Number of employees (%)

No stressors reported 14 (26)

Time pressure 12 (22)

High work load 9 (17)

Equipment missing or unavailable 8 (15)

Understaffed/No help when needed (e.g., from runners) 8 (15)

Lack of respect from management 5 (9)

Interviewed employees were also asked to rate their level of perceived personal control in 

how they do their jobs on a scale from 0 (none) to 10 (very much). Fifty-three employees 

answered this question; the median response was 6.8. Figure 3 shows the distribution of 

responses to this question. Twenty-one percent of scores were between 0–3 (low perceived 

personal control), 21% were between 4–6 (moderate perceived personal control), and 58% 

were between 7–10 (high perceived personal control) [Clark et al. 2011].

Figure 3. Reported perceived personal control in completing one’s job (N = 53).
Page 14

We also asked about the following psychosocial factors during the interviews: time 

pressure, being yelled or cursed at by managers, social support among coworkers, and 

whether managers were perceived as approachable for reporting health and safety concerns. 

Employees were asked to respond “yes” or “no” to each question, and to explain their 

answer. Table 5 describes the results of the yes/no portion of these questions.

Table 5. Responses to yes/no questions about psychosocial factors 

Question Number (%) of “yes” 

responses

Do you have enough time to do your job? (N = 53) 37 (70)

Do you feel your coworkers are supportive of one 

another? (N = 55)

39 (71)

Do you believe management is easy to talk to when it 

comes to reporting health concerns? (N = 50)

36 (72)

Has your supervisor ever yelled at you? (N = 55) 25 (45)

Has your supervisor ever sworn at you or cursed you? 

(N = 51)

5 (10)

Most interviewed employees (70%) indicated they had enough time to complete their job. 

The most frequently reported reasons for not having enough time to do one’s job included 

equipment not being ready, busy flight schedules, being understaffed or without necessary 

help (e.g., runners), or being “held up” by the actions (or lack thereof) of coworkers. Some 

employees reported that, sometimes, common resources were not shared or were “stolen” 

(e.g., someone takes my supplies then I have to find new ones), which interfered with their 

ability to perform job tasks efficiently.

We asked for more detail regarding the approachability of managers for reporting health 

concerns. The most frequent response from those who said their manager was not 

approachable was that the concern would not be addressed. Some employees noted that they 

felt more comfortable talking to upper managers than their direct supervisor, and several 

reported that upper managers were very empathic and helpful regarding their concern or issue.

Many of those who indicated a supervisor had yelled or cursed at them also noted that it 

was not a common practice. Several individuals said they accept the yelling as part of their 

relationship with their supervisor and are not particularly bothered by it (e.g., “we yell at 

each other”).

Our interviews revealed the most common sources of job stress included time pressure, high 

workload, and limited access to resources. Interviewed employees noted that these issues are 

not constant, which may be why the ratings of job stress were varied and low overall, with 

most employees’ ratings falling at the bottom end of the job stress scale. Nonetheless, 17 

(32%) employees rated their job stress level at 7 or greater, indicating these employees may 

benefit from changes in work organization to decrease time pressure and workload and to 

improve access to resources to complete their tasks.
Page 15

Perceived personal control was explained to employees as how much choice or control 

they have over their jobs, including things such as how to complete their tasks and in what 

order. Ratings of perceived personal control varied; most responses reported a high level 

of perceived control (rating > 7). Eleven individuals (21%) reported feeling a low sense of 

personal control (rating 0–3). Most of these individuals mentioned time pressure, high work 

load, and inconsistency in procedures as major job stressors, which may be tied to their 

feelings of low control. 

A recurring theme in the interviews included the behavior of one’s coworkers impeding 

efficiency and a lack of sense of teamwork. Some individuals thought more help would 

improve their feelings of job stress, either in increased staff or willingness of others to 

assist during periods of high time pressure and workload. Social support from coworkers 

and supervisors is integral to a successful work environment, and improves organizational 

outcomes such as reduced turnover and burnout, and increased work engagement and 

productivity [Leiter and Stight 2009]. 

Research supports a strong association between psychosocial factors and work-related 

MSDs [NIOSH 1997; Warren 2001]. Psychosocial factors may cause chronic increased 

muscle tension, thus making soft tissues more susceptible to the effects of physical stressors. 

Psychosocial factors may also raise awareness of MSD symptoms and affect reporting 

behavior [NIOSH 1997]. For example, the interactive effects of psychosocial factors (e.g., 

high workload, low social support, and low job satisfaction) and physical stressors are related 

to the development of musculoskeletal pain in the lower back [De Beeck and Hermans 

2000; World Health Organization 2010]. A combination of ergonomic, job design (e.g., 

rotation of tasks), and psychosocial interventions may result in a decrease in job stress and 

musculoskeletal pain.

Work Practices Reported During Interviews

Most of the interviewed employees reported taking two scheduled breaks per shift, 30 

minutes for lunch and another break for 20 minutes. Some employees reported having 

problems with access to fluids on hot days because drinks were permitted only in the 

cafeteria and on the dock. Employees reported that hand washing behavior varied depending 

on the job task, but for the most part, employees washed their hands before and after shifts 

and during breaks. The company provided PPE; however, some employees brought their 

own shoes for comfort reasons and gloves because of limited availability of some glove 

types/sizes. Employees reported wearing many types of gloves for all duties including 

cloth, latex, cloth and latex, autoclave (heat resistant), leather, and cut-resistant gloves. The 

company provided the cold room employees with lab coats and winter coats. All interviewed 

employees reported that they wore slip-resistant shoes per company policy; the drivers 

wore steel-toed shoes. In addition, four employees reported wearing some type of hearing 

protection and safety glasses.
Page 16

Review of OSHA Logs

The OSHA Logs for the previous 5 years, 2007–2011, contained reports of 200 injuries and 

2 skin disorders. Musculoskeletal strain, sprain, or pain entries were the most common type 

of injury with 112 cases (56% of injuries). The number and type of injury for 2007–2011 

are described in Figure 4. Musculoskeletal strain, sprain, or pain injuries most commonly 

affected the back and shoulder and the most common causes of injuries were lifting and 

pulling/pushing equipment and falling. Other types of injuries included contusion/abrasion, 

laceration, burn, fracture, foreign object, and insect stings.

Figure 4. OSHA Log injuries by type for years 2007–2011.
Page 17

Conclusions

Employees were exposed to a combination of risk factors for work-related MSDs including 

awkward postures, forceful exertions, and repetitive motions. Musculoskeletal strain, sprain, 

or pain entries were the most common type of injury according to the OSHA Logs. The 

potential exists for autoclave operators and delivery truck drivers to work in hot conditions 

during the summer months. Measures to reduce the potential for heat strain and confined 

space hazards in the autoclave should be implemented. Potential exposure to diesel exhaust 

for loading and unloading dock employees should be reduced. Most employees reported low 

to moderate job stress. The most common sources of job stress included time pressure, high 

workload, and limited access to resources. A lack of social support and teamwork among 

employees was also a common theme reported during interviews.

Recommendations

On the basis of our findings, we recommend the actions listed below. We encourage the 

airline catering facility to use a labor-management health and safety committee or working 

group to discuss our recommendations and develop an action plan. Those involved in the 

work can best set priorities and assess the feasibility of our recommendations for the specific 

situation at the airline catering facility. 

Ergonomics

Many of the recommendations listed below were obtained from The Handbook of Ergonomic 

Design Guidelines [Humantech 2009].

1. Design for adjustability when possible. When designing reaches, design for the 

smallest or shortest people in the working population (5th percentile female). Do not 

design for the average; it excludes most of the working population. 

a. Create a standing hand working height that is adjustable at 38ʺ–47ʺ or fixed at 42ʺ. 

b. Place part bins in front of the employee with less than 16ʺ reaching distance at 

 a vertical height of 24ʺ–70ʺ. 

c. Locate more frequently used items or heavy items 38ʺ–49ʺ above standing surface.

d. Do all work within 22ʺ of the edge of the workstation (horizontal work 

 distance guideline) to eliminate extended reaches.

2. Provide tools to aid in reaching, such as a hook to pull material closer to the employee.

3. Ensure that flow racks have the following dimensions: 38ʺ–49ʺ retrieval height 

(frequent), 38ʺ–62ʺ replenish height (infrequent), rack angles of 0°–30°, and a 

minimum 5ʺ clearance from the top of the bin to the bottom of the next shelf.

4. Cross-train employees for different jobs, and rotate employees through jobs with 

different physical demands to reduce the stress on limbs and body regions. Rotate 

every 2 hours to increase job variability. 
Page 18

5. Provide lift tables or load levelers for palletized materials such as soda, beer, or water. 

A rotating top will help reduce reach distances when access is not available on three 

sides of a pallet.

6. Keep heavy loads close to the body when lifting and carrying.

7. Provide industrial mats for employees who stand for 90% or more of their working 

hours. Mats should be ≥ 0.5ʺ thick, have an optimal compressibility of 3%–4%, have 

beveled edges to minimize trip hazards, and be placed at least 8ʺ under a workstation 

to prevent uneven standing surfaces. Mats should cover the entire area over which the 

employee moves while performing work tasks and be replaced when they appear worn 

out or are damaged.

8. Evaluate the effectiveness of the new engineering and administrative controls. 

Develop a system for employees to provide information and feedback on work 

equipment and procedure modifications.

Cold Rooms

1. Install deflectors in all refrigerator fans in the international cold room. A horizontal 

deflector design with spacers (Figure 5) should improve the volumetric flow and 

efficiency of the refrigerator unit (the less restrictive design should improve airflow 

through the cooling coils). Nonmetal spacers that create an air gap between the 

refrigeration unit and the edge of the deflector will create a thermal break, enhance 

airflow, and eliminate the condensation collection point inherent in the current 

deflector design.

2. Replace old deflectors (Figure 1) with horizontal baffle deflectors (Figure 5).

Figure 5. Suggested fan assembly horizontal deflector design with spacer. Figure by NIOSH.
Page 19

3. Install ceiling baffles in cold rooms where employees spend more than a few hours 

a day to decrease drafts without overly restricting room airflow. These baffles are 

horizontally suspended panels (free hanging nonporous surfaces) intermittently spaced 

throughout the ceiling. A trial-and-error approach can be used for determining baffle 

placement that reduces drafts in fixed work locations.

4. Evaluate using thinner, fingertip-less, or fingerless liner gloves for employees to 

wear under the required plastic gloves when performing work requiring fine manual 

dexterity. We do not recommend natural rubber latex gloves because they can cause 

Type I allergy, such as hives, rhinitis, asthma, and anaphylaxis.

5. Do not wear wet clothes inside the cold room. Dry clothes are essential to achieve 

thermal comfort.

6. Rotate employees performing work requiring fine manual dexterity between warmer 

and colder areas throughout the workday. Rotating every 2 hours will also allow for 

breaks from cold temperatures.

7. Minimize work requiring fine manual dexterity during the food preparation stage, 

when feasible. 

8. Implement a replacement schedule for gloves and other nondisposable PPE that 

includes checking for degradation of the materials, excessive wear, tears, or other 

factors that may impede its effectiveness.

9. Provide hand warmers (e.g., warm air hand dryer) outside of the cold rooms so that 

employees can warm their hands periodically.

Heat

1. Establish a written heat stress prevention program that includes regular breaks and 

access to fluids. 

2. Inform employees and supervisors of OSHA heat safety tools found at http://

www.osha.gov/SLTC/heatillness/heat_index/heat_app.html. The website provides 

information on protective measures they can take on the basis of the heat index at the 

worksite.

3. Ensure that new trucks have air conditioning and repair systems in existing vehicles.

Carbon Monoxide

1. Maintain and inspect trucks following Environmental Protection Agency guidelines 

found at http://www.epa.gov/otaq/im.html to identify high emission vehicles that need repair. 

2. Implement plans to minimize diesel exhaust entering the building during the winter 

season by installing dock-to-truck seals and rerouting truck exhaust.

3. Use air extraction fans, filters attached to tailpipes, and catalytic converters as 

recommended in the Health and Safety Executive guidance document (http://www.hse.

gov.uk/pubns/indg286.html) to reduce diesel exhaust in the workplace.
Page 20

4. Park trucks at the alternative location away from the building, especially during the 

morning start-up activities in the winter. Make sure that dock doors remain closed 

while trucks are not docked to avoid diesel exhaust entering the building.

Policies and Procedures

1. Classify the autoclave as a confined space. The OSHA standard on confined spaces is 

found at http://www.osha.gov/SLTC/confinedspaces/index.html.

2. Establish a written autoclave cleaning procedure. If entry is required for cleaning, 

address confined space requirements including lockout/tagout procedures, air 

monitoring prior to entry, and use of PPE and rescue procedures in accordance with 

the applicable OSHA standards and NIOSH recommendations.

3. Ensure good housekeeping to reduce slips, trips, and falls. The Washington State 

Department of Labor and Industries has restaurant safety materials that provide 

information on footwear, housekeeping, and general awareness tips to prevent slips, 

trips, and falls [Washington State Department of Labor and Industries 2008]. 

4. Replace or repair uneven floors as well as wheels on carts to reduce injuries caused by 

cart accidents.

5. Modify the lifting water SOP to also include soda and other palletized materials. 

Remind employees to keep heavy loads close to the body when lifting and carrying.

6. Present all information (e.g., training, messages to employees, hazard communication 

materials, etc.) in a manner that employees are able to understand, which may include 

languages other than English.

7. Educate employees on the symptoms of cold and heat stress, as well as the importance 

of using the appropriate protective clothing and staying hydrated. Train employees in 

how to appropriately reduce heat (e.g., reacclimatization, and work/rest and hydration 

schedules) and cold stress (e.g., appropriately using PPE, changing wet clothing 

immediately, and taking short breaks to warm hands).

8. Provide drinkable water and cups. Water containers must be cleaned and refilled daily 

and kept in a shaded area. Reevaluate the policy prohibiting water and other drinks in 

the trucks if employees do not have access to a break area every 30 minutes. 

9. Educate employees on MSDs and ergonomics, covering specific operations that have 

been identified by NIOSH or the company as causing or likely to cause MSDs. 

10.Explore and address issues of job stress, particularly the importance of increasing 

teamwork/social support and personal control and decreasing time pressure. An open 

discussion with employees may help identify and address barriers to these issues. 

Otherwise, hiring a consultant with expertise in organizational psychology or a related 

field may be beneficial. The Society for Industrial and Organizational Psychology 

maintains a consultant locator at http://www.siop.org/consultantlocator/search.aspx. 

The American Society of Safety Engineers also maintains directories of qualified 

consultants at http://www.asse.org/practicespecialties/consultants/. Evaluate whether 

increasing staff during peak hours would improve efficiency and lower job stress. 
Page 21

11.Encourage employees to report work-related symptoms (e.g., musculoskeletal, cold, 

and heat stress) to their supervisor. Employees with work-related symptoms should 

promptly seek medical attention from their healthcare provider. 

12.Encourage employees to seek services from their healthcare provider or a mental 

health professional if they are experiencing significant stress-related symptoms that 

are impairing their occupational, social, or other important areas of functioning (e.g., 

engagement in day-to-day tasks, hygiene, etc.). This should be communicated to all 

employees so no individuals feel singled out.

13.Improve communication between managers and employees regarding employee health 

and safety concerns. Employees should feel that managers are interested in knowing 

about their concerns and take them seriously. Employees should be informed what 

actions have been or will be taken regarding their concerns, and concerns should be 

addressed in a timely manner.

14.Encourage employees to participate in safety and ergonomics committees. These 

committees should consist of management, union, and employee representatives.

15.Use injury and illness cases recorded on OSHA Logs and other incident reporting 

systems to look for trends in type of injury or job title to target interventions. This 

may be especially helpful for MSDs since they constituted the majority of OSHA Log 

entries. Information on using OSHA Logs to improve safety and health programs can 

be found at https://www.osha.gov/recordkeeping/handbook/.
Page 22

Appendix A: Occupational Exposure Limits and 

Health Effects

NIOSH investigators refer to mandatory (legally enforceable) and recommended OELs for 

chemical, physical, and biological agents when evaluating workplace hazards. OELs have 

been developed by federal agencies and safety and health organizations to prevent adverse 

health effects from workplace exposures. Generally, OELs suggest levels of exposure that 

most employees may be exposed to for up to 10 hours per day, 40 hours per week, for a 

working lifetime, without experiencing adverse health effects. However, not all employees 

will be protected if their exposures are maintained below these levels. Some may have 

adverse health effects because of individual susceptibility, a pre-existing medical condition, 

or a hypersensitivity (allergy). In addition, some hazardous substances act in combination 

with other exposures, with the general environment, or with medications or personal habits of 

the employee to produce adverse health effects. Most OELs address airborne exposures, but 

some substances can be absorbed directly through the skin and mucous membranes.

Most OELs are expressed as a time weighted average exposure. A time weighted average 

refers to the average exposure during a normal 8- to 10-hour workday. Some chemical 

substances and physical agents have recommended short-term exposure limits or ceiling 

values. Unless otherwise noted, the short-term exposure limit is a 15-minute time weighted 

average exposure. It should not be exceeded at any time during a workday. The ceiling limit 

should not be exceeded at any time.

In the United States, OELs have been established by federal agencies, professional 

organizations, state and local governments, and other entities. Some OELs are legally 

enforceable limits; others are recommendations. 

● The U.S. Department of Labor OSHA permissible exposure limits (29 CFR 1910 

[general industry]; 29 CFR 1926 [construction industry]; and 29 CFR 1917 [maritime 

industry]) are legal limits. These limits are enforceable in workplaces covered under the 

Occupational Safety and Health Act of 1970. 

● NIOSH recommended exposure limits are recommendations based on a critical review 

of the scientific and technical information and the adequacy of methods to identify 

and control the hazard. NIOSH recommended exposure limits are published in the 

NIOSH Pocket Guide to Chemical Hazards [NIOSH 2010]. NIOSH also recommends 

risk management practices (e.g., engineering controls, safe work practices, employee 

education/training, personal protective equipment, and exposure and medical 

monitoring) to minimize the risk of exposure and adverse health effects.

● Other OELs commonly used and cited in the United States include the TLVs, which 

are recommended by ACGIH, a professional organization, and the workplace 

environmental exposure levelsTM, which are recommended by the American Industrial 

Hygiene Association, another professional organization. The TLVs and workplace 

environmental exposure levels are developed by committee members of these 

associations from a review of the published, peer-reviewed literature. These OELs are 
Page 23

not consensus standards. TLVs are considered voluntary exposure guidelines for use 

by industrial hygienists and others trained in this discipline “to assist in the control of 

health hazards” [ACGIH 2014]. Workplace environmental exposure levels have been 

established for some chemicals “when no other legal or authoritative limits exist” 

[AIHA 2014].

Outside the United States, OELs have been established by various agencies and organizations 

and include legal and recommended limits. The Institut für Arbeitsschutz der Deutschen 

Gesetzlichen Unfallversicherung (Institute for Occupational Safety and Health of the German 

Social Accident Insurance) maintains a database of international OELs from European Union 

member states, Canada (Québec), Japan, Switzerland, and the United States. The database, 

available at http://www.dguv.de/ifa/Gefahrstoffdatenbanken/GESTIS-InternationaleGrenzwerte-für-chemische-Substanzen-limit-values-for-chemical-agents/index-2.jsp, contains 

international limits for more than 1,500 hazardous substances and is updated periodically. 

OSHA requires an employer to furnish employees a place of employment free from 

recognized hazards that cause or are likely to cause death or serious physical harm 

[Occupational Safety and Health Act of 1970 (Public Law 91–596, sec. 5(a)(1))]. This is 

true in the absence of a specific OEL. It also is important to keep in mind that OELs may not 

reflect current health-based information.

When multiple OELs exist for a substance or agent, NIOSH investigators generally 

encourage employers to use the lowest OEL when making risk assessment and risk 

management decisions. NIOSH investigators also encourage use of the hierarchy of controls 

approach to eliminate or minimize workplace hazards. This includes, in order of preference, 

the use of (1) substitution or elimination of the hazardous agent, (2) engineering controls 

(e.g., local exhaust ventilation, process enclosure, dilution ventilation), (3) administrative 

controls (e.g., limiting time of exposure, employee training, work practice changes, medical 

surveillance), and (4) personal protective equipment (e.g., respiratory protection, gloves, 

eye protection, hearing protection). Control banding, a qualitative risk assessment and risk 

management tool, is a complementary approach to protecting employee health. Control 

banding focuses on how broad categories of risk should be managed. Information on control 

banding is available at http://www.cdc.gov/niosh/topics/ctrlbanding/. This approach can be 

applied in situations where OELs have not been established or can be used to supplement 

existing OELs.

Ergonomic Evaluation Criteria

Musculoskeletal disorders are those conditions that involve the nerves, tendons, ligaments, 

muscles, spinal discs, and soft tissues of the body. They can be characterized by symptoms 

of pain, aching, numbness, or tingling that may come and go. MSDs can range in severity 

from mild and intermittent to debilitating and chronic. They are not typically the result of 

any instantaneous or acute event (such as a slip, trip, or fall) but reflect a more gradual or 

chronic development. MSDs are diagnosed by a medical history, physical examination or 

other medical tests. Work-related MSDs refer to (1) MSDs in which the work environment 

and the performance of work contribute significantly, or (2) MSDs that are made worse or 
Page 24

longer lasting by work conditions. A substantial body of data provides strong evidence of an 

association between MSDs and certain work-related factors (physical, work organizational, 

psychosocial, individual, and sociocultural). The multifactorial nature of musculoskeletal 

disorders requires a discussion of individual factors and how they are associated with workrelated musculoskeletal disorders. Strong evidence shows that working groups with high 

levels of static contraction, prolonged static loads, or extreme working postures involving the 

neck/shoulder muscles are at increased risk for neck/shoulder MSDs [NIOSH 1997]. Further 

strong evidence shows job tasks that require a combination of risk factors (highly repetitious, 

forceful hand/wrist exertions) increase risk for hand/wrist tendonitis [NIOSH 1997]. Finally, 

strong evidence shows that low-back disorders are associated with work-related lifting 

and forceful movements [NIOSH 1997]. A number of personal factors can also influence 

the response to risk factors for MSDs: age, sex, smoking, physical activity, strength, and 

body measurements. Although personal factors may affect an individual’s susceptibility 

to overexertion injuries/disorders, studies conducted in high-risk industries show that the 

risk associated with personal factors is small compared to that associated with occupational 

exposures [NIOSH 1997].

In all cases, the preferred method for preventing and controlling work-related MSDs is to 

design jobs, workstations, tools, and other equipment to match the physiological, anatomical, 

and psychological characteristics and capabilities of the employee. Under these conditions, 

exposures to risk factors considered potentially hazardous are reduced or eliminated.

Carbon Monoxide

Carbon monoxide is produced by incomplete burning of carbon-containing materials such 

as diesel fuel. In previous evaluations of employees’ exposures to diesel exhaust, NIOSH 

investigators have concluded that a potential health hazard exists when employees are 

experiencing occupational exposures that exceed ambient background levels – such as when 

diesel engines are operated close to work areas – and have recommended adopting measures 

to reduce exposures whenever feasible [NIOSH 1992, 1999]. Although these evaluations 

often have included measuring employees’ exposures to a variety of airborne contaminants, 

the basic conclusions and recommendations have applied regardless of the exposure levels 

measured. Therefore, exposure measurements may be more useful for comparing exposures 

before and after controls are established than in establishing that a potential hazard exists.

Diesel Exhaust

Diesel exhaust is a complex mixture of thousands of gases and fine particles (commonly 

known as soot) that contains more than 40 potentially toxic compounds [Environmental 

Protection Agency 2002]. The particulate fraction of diesel exhaust is composed of 

microscopic cores of elemental carbon onto which are adsorbed thousands of substances 

[NIOSH 1988; OSHA 1988]. The adsorbed material contributes 15% to 65% of the total 

particulate mass and includes compounds such as polycyclic aromatic hydrocarbons, many 

of which are possibly carcinogenic [NIOSH 1988; OSHA 1988; Air Resources Board 1998]. 

Because of their small size (< 2.5 micrometers in aerodynamic diameter) [Wichmann 2007], 

diesel exhaust particles can be inhaled deeply into the lungs where they are more difficult to 
Page 25

clear [Hinds 1999]. Some of the main toxic gases in diesel exhaust are oxides of nitrogen, 

sulfur, and carbon [NIOSH 1988; OSHA 1988].

Acute health effects of diesel exhaust exposure include irritation of the eyes, nose, throat, 

and lungs, and it can cause cough, headache, lightheadedness, and nausea [Reger and 

Hancock 1980; Gamble et al. 1987; Sydbom et al. 2001]. Exposure to diesel exhaust can 

also cause inflammation in the lungs, which may aggravate chronic respiratory symptoms 

and asthma. Chronic exposures are associated with cough, increased sputum production, and 

lung function changes [Ulfvarson and Alexandersson 1990; Sydbom et al. 2001]. Whether a 

person experiences these acute or chronic health effects depends on the magnitude of their 

exposures and on individual susceptibility.

Diesel exhaust is considered a probable human carcinogen [IARC 1989]. On the basis of 

the results of laboratory animal and human epidemiology studies, NIOSH considers whole 

diesel exhaust emissions a potential occupational carcinogen [NIOSH 1988]. Human 

epidemiology studies suggest an association between occupational exposure to whole diesel 

exhaust emissions and lung cancer [NIOSH 1988; Air Resources Board 1998; Garshick et al. 

2004; Attfield et al. 2012; Silverman et al. 2012], while studies of rats and mice exposed to 

whole diesel exhaust, and especially to the particulate portion, confirm an association with 

lung tumors [NIOSH 1988; OSHA 1988; Air Resources Board 1998]. NIOSH has stated that 

“excess cancer risk for workers exposed to diesel exhaust has not yet been quantified, but the 

probability of developing cancer should be reduced by minimizing exposure” [NIOSH 1988]. 

Federally mandated OELs exist for nitrogen monoxide, nitrogen dioxide, sulfur dioxide, and 

carbon monoxide; however, at the present time, no federally mandated OELs exist for 

diesel exhaust. 
Page 26

References

ACGIH [2014]. 2014 TLVs® and BEIs®: threshold limit values for chemical substances and 

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Keywords: North American Industry Classification System 722310 (Food Service Contractors), Michigan, airline catering, ergonomics, musculoskeletal injuries, heat, cold rooms, 

job stress
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The Health Hazard Evaluation Program investigates possible health hazards in the workplace 

under the authority of the Occupational Safety and Health Act of 1970 (29 U.S.C. § 669(a)

(6)). The Health Hazard Evaluation Program also provides, upon request, technical assistance 

to federal, state, and local agencies to investigate occupational health hazards and to prevent 

occupational disease or injury. Regulations guiding the Program can be found in Title 42, Code 

of Federal Regulations, Part 85; Requests for Health Hazard Evaluations (42 CFR Part 85).

Disclaimer

The recommendations in this report are made on the basis of the findings at the workplace 

evaluated and may not be applicable to other workplaces.

Mention of any company or product in this report does not constitute endorsement by NIOSH.

Citations to Web sites external to NIOSH do not constitute NIOSH endorsement of the 

sponsoring organizations or their programs or products. NIOSH is not responsible for the 

content of these Web sites. All Web addresses referenced in this document were accessible as of 

the publication date.

Acknowledgments

Desktop Publisher: Shawna Watts 

Editor: Ellen Galloway 

Data Analysis and Literature Review: Wei Gong

Logistics: Donnie Booher

Medical Field Assistance: John Gibbins

Engineering Drawings: Jevon Lambright

Availability of Report

Copies of this report have been sent to the employer, employees, and union at the facility. 

The state and local health department and the Occupational Safety and Health Administration 

Regional Office have also received a copy. This report is not copyrighted and may be freely 

reproduced. 

This report is available at http://www.cdc.gov/niosh/hhe/reports/pdfs/2011-0131-3221.pdf.

Recommended citation for this report:

NIOSH [2014]. Health hazard evaluation report: evaluation of ergonomic risk factors, 

thermal exposures, and job stress at an airline catering facility. By Ramsey JG, Musolin 

K, Ceballos D, Wiegand D, Mead K. Cincinnati, OH: U.S. Department of Health and 

Human Services, Centers for Disease Control and Prevention, National Institute for 

Occupational Safety and Health, NIOSH HHE Report No. 2011-0131-3221.
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