Heat-Related Deaths Among Crop Workers

[Guest guest]

June 20, 2008 / 57(24);649-653 http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5724a1.htm?s_cid=mm5724a1_e

Heat-Related

Deaths Among Crop Workers --- United

States, 1992--2006

Workers

employed in outdoor occupations such as farming are exposed to hot and humid

environments that put them at risk for heat-related illness or death. This

report describes one such death and summarizes heat-related fatalities among

crop production workers in the United

States during 1992--2006. During this

15-year period, 423 workers in agricultural and nonagricultural industries were

reported to have died from exposure to environmental heat; 68 (16%) of these

workers were engaged in crop production or support activities for crop

production. The heat-related average annual death rate for these crop workers

was 0.39 per 100,000 workers, compared with 0.02 for all U.S. civilian

workers. Data aggregated into 5-year periods indicated that heat-related death

rates among crop workers might be increasing; however, trend analysis did not

indicate a statistically significant increase. Prevention of heat-related deaths

among crop workers requires educating employers and workers on the hazards of

working in hot environments, including recognition of heat-related illness

symptoms, and implementing appropriate heat stress management measures.

Information

for the illustrative case described in this report was collected by the

Agricultural Safety and Health Bureau of the North Carolina Department of

Labor. For the nationwide analysis, fatality data were obtained from the Bureau

of Labor Statistics (BLS) Census of Fatal Occupational Injuries (CFOI) (1).* A heat-related death was identified

in CFOI as an exposure to environmental heat (BLS Occupational Injury and

Illness Classification System [OIICS] event/exposure code 321), with the nature

of injury attributed to effects of heat and light (OIICS nature code 072). A

crop worker death was indicated where the industry in which the decedent worked

was crop production or support activities for crop production.† Fatality

rates were calculated as an average annualized rate per 100,000 workers during

the 15-year study period for civilian noninstitutionalized workers aged >15

years. The numerator was the total of all fatalities during the 15-year period;

the denominator was the total of the annual average worker population during the

same period. Estimates of the number of workers employed were derived from the

U.S. Current Population Survey (CPS) (2).§

To examine trends in fatality rates during the study period, data were

aggregated in 5-year periods because the numbers of fatalities for several

individual years in the study period were too low to meet BLS publishing

criteria. Poisson regression was used to estimate confidence intervals for

these aggregate rates.

Case

Report

In

mid-July 2005, a male Hispanic worker with an H-2A work visa (i.e., a

temporary, nonimmigrant foreign worker hired under contract to perform farm

work) aged 56 years was hand-harvesting ripe tobacco leaves on a North Carolina farm. He

had arrived from Mexico

4 days earlier and was on his third day on the job. The man began work at

approximately 6:00 a.m. and took a short mid-morning break and a 90-minute

lunch break. At approximately 2:45 p.m., the employer's son observed the man

working slowly and reportedly instructed him to rest, but the man continued working.

Shortly thereafter, the man's coworkers noticed that he appeared confused.

Although the man was combative, his coworkers carried him to the shade and

tried unsuccessfully to get him to drink water. At approximately 3:50 p.m.,

coworkers notified the employer of the man's condition. At 4:25 p.m., the man

was taken by ambulance to an emergency department, where his core body

temperature was recorded at 108°F (42°C) and, despite treatment, he died. The

cause of death was heat stroke. On the day of the incident, the local high

temperature was approximately 93°F (34°C) with 44% relative humidity and clear

skies. The heat index was in the range of 86°--101°F (30°--38°C) at mid-morning

and 97°--112°F (36°--44°C) at mid-afternoon.¶ Similar conditions had

occurred during the preceding 2 days.

The man

had been given safety and health training on pesticides but nothing that

addressed the hazards and prevention of heat-related stress. He reportedly only

spoke Spanish. Fluids, such as water and soda, were always available to the

workers in the field; however, whether the man drank any of these fluids is

unknown.

Heat-Related

Fatalities, 1992--2006

During

1992--2006, a total of 423 worker deaths from exposure to environmental heat

were reported in the United States, resulting in an average annual fatality

rate of 0.02 deaths per 100,000 workers. Of these 423 deaths, 102 (24%)

occurred in workers employed in the agriculture, forestry, fishing, and hunting

industries (rate: 0.16 per 100,000 workers), and of these, 68 (67%) occurred in

workers employed in the crop production or support activities for crop

production sectors, resulting in an average annual fatality rate of 0.39 deaths

per 100,000 crop workers (Table).

Analysis of fatality rates by 5-year periods suggests an increase in rates over

time; however, those rates were based on small numbers of deaths, and the

increase over time was not statistically significant (Figure).

During

1992--2006, nearly all deceased crop workers were male,** and 78% were aged

20--54 years (Table).

During 1992--2006, the birth country was unknown for 46% of the decedents;

however, during 2003--2006, approximately 20 (71%) of the 28 deceased crop

workers were from Mexico or

Central and South America. Nearly 60% of all

heat-related deaths among crop workers occurred in July, and most deaths

occurred in the afternoon. Although 21 states reported heat-related deaths

among crop workers, California, Florida, and North Carolina

accounted for 57% of all deaths, with North

Carolina having the highest annualized rate.

Reported by: RC Luginbuhl, MS, North

Carolina Dept of Labor. LL , PhD, DN Castillo,

MPH, Div of Safety Research, National Institute for Occupational Safety and

Health; KA Loringer, ND, EIS Officer, CDC.

Editorial Note:

During

1992--2006, a total of 68 crop workers died from heat stroke, representing a

rate nearly 20 times greater than for all U.S. civilian workers. The majority

of these deaths were in adults aged 20--54 years, a population not typically

considered to be at high risk for heat illnesses (3).

In addition, the majority of these deaths were among foreign-born workers.

Persons

who work outside in hot and humid conditions are at risk for heat-related

mortality and morbidity. Heat-related illnesses range from minor heat cramps or

rash to heat exhaustion, which is more serious and can lead to heat stroke,

which can result in death if medical attention is not provided immediately.

Heat stroke is characterized by a body temperature of >103°F (>39°C);

red, hot, and dry skin (with no sweating); rapid, strong pulse; throbbing

headache; dizziness; nausea; confusion; and unconsciousness. Crop workers might

be at increased risk for heat stroke because they often wear extra clothing and

personal protective equipment to protect against pesticide poisoning or green

tobacco illness (transdermal nicotine poisoning). Employers and workers must be

aware that heat-related illness, which can have symptoms similar to pesticide

poisoning and green tobacco illness, requires immediate attention. The high

proportion of heat-related deaths among foreign-born workers indicates that

training and communications regarding the risk for heat-related illnesses

should be provided in the workers' native language.

Guidance

to help agricultural employers establish a heat-illness prevention program is

available from CDC and the U.S. Environmental Protection Agency (4,5). In addition, the Department of the

Army and Air Force has published a technical bulletin that provides strategies

for employers to control heat stress (6).

Heat-related safety materials in English and Spanish are available from several

other sources, including the California Division of Occupational Safety and

Health†† and the North Carolina Department of Labor.§§

California and Washington state have recently enacted regulations requiring

that employers take action to prevent heat-related illnesses and deaths among

their workers, including providing training to supervisors and workers and

ensuring the availability of fluids (7,8).

These regulations were prompted by deaths and illnesses in both states in

recent years.

The

findings in this report are subject to at least four limitations. First,

certain fatality rates had to be calculated as average annualized rates for the

entire 15-year study period because small numbers prevented publication

according to BLS publishing criteria. This aggregation obscured variability

between years. Second, CPS estimates likely underestimated the number of crop

workers because of the seasonal nature of the work and because the CPS relies

on stable residences for sequential interviews. An underestimate of the worker

population would have resulted in an overestimation of the fatality rates.

Third, heat-related deaths were likely underreported because heat stroke was

not recognized at the time of death, was not indicated as a contributing factor

on the death certificate (3),

or was not recognized by the state agencies as meeting the case definition for

an injury-related death in CFOI. Finally, the fatality rates for 5-year periods

were based on small numbers with large confidence intervals, and the data do

not allow an assessment of whether increased numbers over time might be a

reflection of increased awareness and reporting.

The

illustrative case described in this report and another case previously reported

by CDC (9) suggest that some employers

might not have heat stress management programs in place. Agricultural employers

should develop and implement heat stress management measures that include 1)

training for field supervisors and employees to prevent, recognize, and treat

heat illness, 2) implementing a heat acclimatization program, 3) encouraging

proper hydration with proper amounts and types of fluids, 4) establishing

work/rest schedules appropriate for the current heat indices, 5) ensuring

access to shade or cooling areas, 6) monitoring the environment and workers

during hot conditions, and 7) providing prompt medical attention to workers who

show signs of heat illness (5,6,10).

Employers and workers should be vigilant for signs of heat illness, not only in

themselves but in their coworkers, and be prepared to provide and seek medical

assistance.

Acknowledgments

The

findings in this report are based, in part, on contributions by J Myers, MS,

National Institute for Occupational Safety and Health, CDC.

References

Bureau of Labor Statistics. Bureau of Labor

Statistics handbook of methods. Washington,

DC: US Department of Labor,

Bureau of Labor Statistics; 2007. Available at http://www.bls.gov/opub/hom/homch9_a1.htm.

Bureau of Labor Statistics. Current Population

Survey, 1992--2006 (microdata files) and labor force data from the Current

Population Survey. In: BLS handbook of methods. Washington, DC:

US Department of Labor, Bureau of Labor Statistics; 2003. Available at http://www.bls.gov/cps/home.htm.

CDC.

Heat-related deaths---United States, 1999--2003. MMWR 2006;55:796--8.

CDC. Working in hot environments. Cincinnati, OH:

US Department of Health and Human Services, CDC, National Institute for

Occupational Safety and Health; 1986. DHHS (NIOSH) publication 86-112.

Available at http://www.cdc.gov/niosh/hotenvt.html.

US Environmental Protection Agency. A guide to

heat stress in agriculture. Washington,

DC: US Environmental

Protection Agency; 1993. EPA-750-b-92-001. Available at http://www.epa.gov/oecaagct/awor.html.

Department of the Army and Air Force. Heat stress

control and heat casualty management. Washington, DC:

Department of the Army and Air Force; 2003. Available at http://chppm-www.apgea.army.mil/documents/tbmeds/tbmed507.pdf.

California

Division of Occupational Safety and Health. Heat-related illness

prevention. Oakland, CA:

California

Division of Occupational Safety and Health; 2007. Available at http://www.dir.ca.gov/dosh/heatillnessinfo.html.

Washington State Department of Labor and

Industries. Outdoor heat-related illness (heat stress). Olympia, WA:

Washington State Department of Labor and Industries; 2008. Available at http://www.lni.wa.gov/safety/topics/atoz/heatstress/default.asp.

CDC. Migrant farm worker dies from heat stroke

while working on a tobacco farm---North

Carolina. town,

WV: US Department of Health

and Human Services, CDC, National Institute for Occupational Safety and

Health; 2007. FACE report 2006-04. Available at http://www.cdc.gov/niosh/face/in-house/full200604.html.

CDC. Criteria for a recommended standard:

occupational exposure to hot environments (revised criteria 1986). Cincinnati, OH:

US Department of Health and Human Services, CDC, National Institute for

Occupational Safety and Health; 1986. DHHS (NIOSH) publication no. 86-113.

Available at http://www.cdc.gov/niosh/86-113.html.

* For

this report, CDC used a CFOI research file provided by BLS, which excluded

deaths in New York City.

Because of confidentiality restrictions, individual case information from the

CFOI data cannot be reported; information for the case described in this report

was obtained solely from the North Carolina Department of Labor field

investigation.

† Because of changes to the industry

classification system in 2003, two comparable, though not identical,

classification systems were used: the Standard Industrial Classification (major

group 01 and 07, excluding industry group 078) for 1992--2002 and the North

American Industry Classification System (NAICS) (industry codes 111 and 11511)

for 2003--2006.

§ CPS labor counts included workers in

crop production industries (NAICS code 111) and support activities for

agriculture and forestry (code 115). The latter industry category includes some

workers who do not specifically support crop production activities. However,

the inclusion of a small number of animal production and forestry support

workers in the denominator value should have little influence on the crop

worker fatality rate.

¶ The heat index, an indicator of the

combined physiologic effect of air temperature and relative humidity, is

presented in this report as a range, which is estimated by using the

temperature and humidity to calculate the minimum value and then adding 15°F.

This method better reflects exposure conditions in the field under clear skies.

Additional information available at http://www.nws.noaa.gov/om/heat/heat_wave.shtml.

** Data

are not reported by sex because they do not meet BLS publication criteria.

†† Available at http://www.dir.ca.gov/dosh/heatillnessinfo.html.

§§ Available at http://www.nclabor.com/pubs.htm.

Table

Return

to top.

Figure

Return

to top.

Use of

trade names and commercial sources is for identification only and does not

imply endorsement by the U.S. Department of Health and Human Services.

References to non-CDC sites on the Internet are

provided as a service to MMWR readers

and do not constitute or imply endorsement of these organizations or their

programs by CDC or the U.S. Department of Health and Human Services. CDC is

not responsible for the content of pages found at these sites. URL addresses

listed in MMWR were current as

of the date of publication.

Amy K. Liebman, MPA

Migrant Clinicians Network

5210 River Circle

Quantico, MD 21856

410.860.9850

aliebman@...

Migrant Clinicians Network is a force for

justice in healthcare for the mobile poor.