Grounds maintenance workers, including landscaping and tree care workers, may be exposed to numerous physical, chemical, and biological hazards while performing work, especially during the summer months [1,2]. According to the Bureau of Labor Statistics [3], grounds maintenance workers are more than two times more likely to be injured on the job compared with all workers across all occupations (189 injuries per 10,000 full-time employees vs. 87). The fatal injury rate for workers in grounds maintenance (20 per 100,000 workers) is 5 times the rate of all workers across all occupations (4 per 100,000 workers) [4]. BLS also reported that there were more than 1.3 million grounds maintenance workers in 2019, and that number is projected to grow by more than 10% over the next 10 years, which is much faster than the average employment growth for other occupations [5]. Adequate training and appropriate personal protective equipment are vital in protecting workers’ safety and health.

Background

Landscaping workers perform tasks such as mowing and edging grass, spreading fertilizers, mulching, and planting trees, flowers, and shrubs. Tree care workers trim and prune trees and shrubs, as well as diagnose and treat tree diseases. Grounds maintenance crews often work on short timelines, to maximize the amount of work performed during day light hours. If employers have staffing issues, heavy workloads may be more likely as fewer workers are available to complete job tasks.

Hazards associated with heat and muscle exertion during landscaping and tree care work

Grounds maintenance workers often work long hours outside in the heat and in direct sunlight. These conditions can lead to heat exposure and heat stress. Heat stress (an increase in the heat stored in the body [6,7] can result in heat-related illnesses, such as, heat stroke, heat exhaustion, heat cramps, or heat rashes. Heat stress may also be increased by the metabolic heat (created by the body internally) from physical exertion. Examples of physical exertion include landscaping and tree care work that may require workers to lift or carry heavy equipment, especially when unloading equipment from transport vehicles. In addition, workers may carry backpack blowers and lift bags of dirt, shrubs, trees, and decorative rocks. Muscle damage from doing strenuous work in a hot environment can also lead to rhabdomyolysis or rhabdo [1,5,8].

What is rhabdo?

Rhabdo is the rapid breakdown of muscle and can be caused by many different things including increased core body temperature and overworking the muscles. [7]. Once muscle cell contents are released into the blood, they can cause damage to many parts of the body including the heart and kidneys [6,7,8]. If not treated promptly, rhabdo can result in death or permanent disability [7].

Symptoms of rhabdo include the following:

• Muscle cramps, aches, or pains worse than expected for the exertion done
• Dark (tea- or cola-colored) urine
• Feeling weak or tired
• Inability to complete routine physical job tasks or finish routine work.

If you suspect you might have rhabdo increase fluid intake and seek medical attention immediately [8].

Preventing Rhabdo and Other Heat-related Illnesses

Employers should take the following steps to reduce the risk of heat-related illnesses:

• Have a heat stress management policy to decrease risk of heat-related illness that could lead to rhabdo. Follow the guidelines presented in the NIOSH Heat Stress recommendations.
• Make annual medical evaluations available to workers and ensure pre-employment screening includes assessment of heat stress and rhabdo risk factors.
• Train workers in a language and vocabulary they understand to ensure they are aware of the risk factors for heat-related illnesses, including rhabdo.
• Allow workers time to acclimatize. Gradually introduce new workers or those who have been off the job for over 2 weeks (i.e. vacation, etc.) to working in the heat over a 7–14-day period.
• Provide clean, fresh water and encourage workers to drink 1 cup every 15–20 minutes. Remind workers to rehydrate with low sugar and low caffeine drinks and to avoid alcohol use in hot weather, as all these can worsen dehydration.
• During prolonged sweating lasting more than 2 hours, provide workers with sports drinks that contain balanced electrolytes to replace those lost during sweating (as long as the concentration of electrolytes/carbohydrates does not exceed 8% by volume) [6].
• Schedule regular rest breaks for workers in safe, air-conditioned, or shaded areas. If a worker develops signs or symptoms of heat stroke (confusion, trouble completing routine tasks, etc.), this should be considered a medical emergency. Other symptoms of heat stroke may include dizziness, nausea, headache, altered mental status, slurred speech, seizures, and followed by loss of consciousness.
• If you think a worker is suffering from heat stroke, take the following steps:
  • Call 911 after getting the workers out of the hot environment.
  • If the worker is alert, encourage frequent sips of cool water.
  • If the worker does not appear alert and able to follow instructions, do not attempt to give them anything by mouth.
  • If possible, start misting fans or an ice bath while waiting for 911. [6,8,9]

Additional employer recommendations for heat-illnesses, including rhabdo:

• Allow and encourage workers to seek medical care when they have heat-related illness or rhabdo symptoms. Let workers know they can return to work once they are cleared by their doctor. Advise workers whether the cost of medical care will be covered by the employer worker compensation program.
• Encourage workers to take sick leave when sick, as many illnesses increase the risk for rhabdo.
• Schedule heavy work during the coolest parts of day.
• Provide your employees with mechanical lifting devices and manual carts to prevent overexertion.
• Consult the NIOSH Safety and Health Topic Page on Rhabdomyolysis for more information about symptoms, prevention, and treatment of rhabdo. [7-9]

Workers should take the following steps to reduce the risk of heat-related illnesses:

• Drink 1 cup of water every 15–20 minutes.
• Take periodic rest breaks.
• Use heat-protective clothing (e.g., wetted overgarments).
• Wear wide-brimmed hats to protect against sun (heat) exposure.
• Do not drink alcohol before or after a work shift; alcohol may lead to dehydration. [6,7,9]

Additional worker recommendations:

• Stay home from work when you’re sick with any illness. Many illnesses (such as the flu) and medications (including over the counter medication like cold and/or allergy meds, prescription meds, and dietary supplements) may increase your risk for rhabdo. Staying home when sick will also protect your coworkers from getting sick.
• If you start experiencing any rhabdo or other heat-related illness symptoms, stop your current activity right away, cool down, start drinking fluids, and seek immediate care at the nearest medical facility.
• Use mechanical lifting devices and manual carts when possible and provided by your employer. [7,8]

Sarah Hughes, MPH, is a Research Health Scientist in the NIOSH Division of Science Integration.

Susan Afanuh, MA, is a Technical Information Specialist in the NIOSH Division of Science Integration.

More Information

Heat Stress Resources:

• NIOSH Heat Stress
• NIOSH Rhabdomyolysis
• OSHA Safety and Health Topics: Heat Stress
• OSHA Technical Manual Section III: Chapter 4 – Heat Stress

NIOSH Resources in Spanish

• NIOSH Fast Facts: Protecting Yourself from Heat Stress
• Preventing Heat-related Illness or Death of Outdoor Workers
• OSHA-NIOSH INFOSHEET: Protecting Workers from Heat Illness

Resources on Landscaping and Outdoor Work

• OSHA Campaign to Prevent Heat Illness in Outdoor Workers
• NIOSH FACE reports on landscaping services
• CDC – NIOSH Fatality Assessment and Control Evaluation (FACE) Program: Investigation Reports

NIOSH Resources in Spanish

• Landscaping topic page
• Outdoor workers topic page

NIOSH lifting equation

Ergonomics and musculoskeletal disorders: NIOSH Lifting Equation App: NLE Calc. Safety and Health Topic Page

Lifting and Awkward Postures (non-NIOSH resources)

• Safety Tips Sheet No. 2: Reducing the Risk of Lifting Injuries in the Landscape and Horticultural Industries (National Association of Landscape Professionals (NALP) (formerly Professional Landcare Network (PLANET)) Also available in Spanish
• Backs & Lifting Training Guide. Electronic Library of Construction Safety & Health (elcosh)
• How Much Am I Allowed to Lift? Electronic Library of Construction Safety & Health (elcosh)
• Guidelines for lifts involving trunk-twisting angle of +/- 30 degrees. Ohio Bureau of Workers’ Compensation Presents diagrams showing postures and weights that are likely to constitute an over exertion situation

Endnotes

1. NIOSH [2008]. Fatal injuries among landscape service workers. Fact Sheet. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2008–144. https://www.cdc.gov/niosh/docs/2008-144/
2. NIOSH [2015]. Hazards to outdoor workers. Safety and Health Topic Page. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. https://www.cdc.gov/niosh/topics/outdoor
3. BLS [2020]. TABLE R100. Incidence rates for nonfatal occupational injuries and illnesses involving days away from work per 10,000 full-time workers by occupation and selected events or exposures leading to injury or illness, private industry, 2019. Washington, DC: Bureau of Labor Statistics. https://www.bls.gov/iif/oshwc/osh/case/cd_r100_2019.htm
4. BLS [2020]. Table 5. Fatal work injury rates per 100,000 full-time equivalent workers by selected occupations, 2019. Washington, DC: Bureau of Labor Statistics. https://www.bls.gov/news.release/cfoi.t05.htm
5. BLS [2021]. Grounds maintenance workers. In: Occupational Outlook Handbook. Washington, DC: Bureau of Labor Statistics.  https://www.bls.gov/ooh/building-and-grounds-cleaning/grounds-maintenance-workers.htm
6. NIOSH [2016]. Occupational exposure to heat and hot environments. Criteria for a Recommended Standard. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2016–106. www.cdc.gov/niosh/docs/2016-106
7. NIOSH [2020]. Heat stress. Safety and Health Topic Page. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. www.cdc.gov/niosh/topics/heatstress
8. NIOSH [2019]. Rhabdomyolysis. Safety and Health Topic Page. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. www.cdc.gov/niosh/topics/rhabdo
9. NIOSH [2011]. Protecting workers from heat illness. OSHA NIOSH Infosheet. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2011–174. https://www.cdc.gov/niosh/docs/2011-174/