Occupational Research Agenda for Northwest Forestlands



THE DISEASES AND INJURIES experienced in forestland work range widely in type, severity, and frequency. The incidents experienced by those in forestry and logging can be tragic or disabling. A great strength of the forestry industry, demonstrated through this project and in previous work conducted by industry and government, is the willingness to share information and learn from experience to prevent future occurrences.

Participants identified five priority research areas in this category including hearing loss, heat and cold stress, musculoskeletal disorders, skin disorders, and traumatic injuries.


Hearing loss is one of the most common occupational diseases in the United States, and once the loss is acquired, it is irreversible. Noise induced hearing loss, while widespread, is completely preventable. Although hearing loss may result from an acute traumatic injury, it is more likely to develop gradually as a result of chronic exposure to agents which damage the ear or hearing process. Noise is the most important occupational cause of hearing loss, but solvents, metals, asphyxiants (causing illness or death from lack of oxygen), and heat may also play a role.

[NIOSH NORA: Hearing Loss]


Noise Induced Hearing Loss (NIHL) is a great concern for those who work in the forest industry as it is one of the most common occupational diseases in the United States and is irreversible once acquired. Hearing loss hinders personal communication, which can negatively affect social interactions and present a safety hazard. Temporary, reversible hearing loss may result from short term exposure; however, prolonged occupational exposures, lasting 40 years or more, can gradually produce permanent damage. Noise is the most important occupational cause of hearing loss, but solvents, metals, asphyxiants and heat may also play a role. Exposure to noise, combined with other forces or substances, can result in hearing losses greater than those resulting from exposure to noise or other agents alone.

A Center-funded study on vibration and noise exposure in western Washington state found that forestry workers have substantial over exposures to noise (by OSHA and NIOSH criteria) and, with continued exposure, these workers will likely experience noise induced hearing loss.10 While this condition is irreversible once acquired, it can be prevented through the use of personal protective equipment, engineering, and administrative controls. Recommended strategies include:

  • enclosure of operator cabs and engine compartments on heavy equipment
  • active noise control headsets, incorporating communications capability
  • effective hearing conservation and training programs
  • consistent and proper use of appropriate hearing protection devices
  • increased distance between workers and equipment producing high noise levels
  • purchase and use of quieter equipment
Project participants expressed general concern about noise induced hearing loss among forest workers frequently exposed to noise from chain saws and other machinery. Many participants advocated proper use of hearing protection among workers.

  • Define and gather more data on noise induced hearing loss risk associated with various forestry and logging tasks
  • Develop new methods and technologies for controlling noise and improving hearing protector effectiveness
  • Define the prevalence of noise exposure and the risk of occupational hearing loss in the forest industry
  • Examine the relationship between middle ear function and visual perception
  • Aggregate and assess currently available databases
  • Correlate worker performance with communication ability
  • Investigate the relationship between noise and non-auditory effects such as hypertension and psychological stress
  • Define hazardous parameters of impulsive versus continuous-type noise exposures
  • Analyze ear damaging properties of industrial chemicals and agents and their interaction with noise
  • Develop methods for determining nonoccupational contributors to hearing loss
  • Train clinicians, physicians, and nurses on noise induced hearing loss, including how to refer patients for hearing tests
  • Educate workers on a regular basis regarding the causes of noise induced hearing loss and appropriate preventative measures
  • Use behavioral survey tools to develop training and education programs that address workers' beliefs, attitudes, and intentions about hearing loss prevention
  • Develop materials and programs that involve the worker in the hearing conservation and noise control processes
  • Refine strategies to overcome barriers to wearing hearing protection

Berger E. Noise and Hearing Conservation Manual. 4th edition. Akron, OH: American Industrial Hygiene Association, 1986.

Royster JD, Royster LH. Hearing Conservation Programs: Practical Guidelines for Success. Chelsea, MI: Lewis Press, 1990.

Siebens D. Noise and hearing loss in agriculture, forestry, and fisheries. In: Safety and Health in Agriculture, Forestry, and Fisheries (Langley RL, McLymore, RL, Meggs WJ and Roberson GT eds). Rockville: Government Institutes, Inc, 1997. pp. 59-65.

Suter AH, Franks JR. A Practical Guide to Effective Hearing Conservation Programs in the Workplace. DHHS 90-120. Cincinnati, OH: NIOSH, 1990.

US NIOSH. Occupational Noise Exposure, Criteria for a Recommended Standard. DHHS 98-126. Cincinnati, OH: NIOSH, 1998.

US OSHA. Occupational Noise Exposure: Hearing Conservation Amendment - Final Rule. Federal Register 48:9736-84 (1983).

US OSHA. Occupational Safety and Health Standards, National Consensus Standards and Established Federal Standards. Federal Register 36:10518 (1971).

Noise and Hearing Loss. NIH Consensus Statement Online. Jan 22-24, 1990. Online: http://consensus.nih.gov/1990/1990NoiseHearingLoss076html.htm.

US NIOSH review site covering noise and hearing conservation. Online: http://www.cdc.gov/niosh/topics/noise/.


Working under hot or cold conditions is part of the normal routine of any outdoor occupation in the Northwest. These temperature extremes can affect both worker performance and health. Cold extremes can cause hypothermia, while hot temperatures can lead to heat exhaustion. Both heat and cold are known to decrease manual dexterity, increase discomfort, and in some cases, affect cardiovascular health. Heat stress can be aggravated by the use of personal protective equipment. Other contributing factors to negative health effects from heat and cold stress include level of hydration, duration of exposure, degree of physical demand, age of worker, and worker health. Injury and illness associated with heat and cold stress are generally underreported.



The Northwest has a diverse geography and is affected by all types of weather. The western coastline and mountainous regions generally experience milder temperatures with heavy rainfall, while the inland northwest and lowland areas are typically dry and hot. Alaska stands out from the lower northwest, with greater temperature extremes, heavy winds, and snowfall.

Cold extremes can cause hypothermia, frostbite, and immersion foot (from cold water immersion). Hypothermia occurs at temperatures as high as 65 degrees Fahrenheit, especially when conditions are wet or the worker has been sweating. General risk factors for cold-related illnesses include inadequate or wet clothing, drug use, another illness, gender (male death rates are greater than female), age and immobilization. In the Northwest, Alaska hosts one of the most hazardous environments for cold–related injury with its low temperatures, great distances, seasonal darkness, heavy rains, high winds and icing. This is reflected in the Alaska Trauma Registry for the period 1991 to 1995 where 327 persons were hospitalized from cold-related injuries, of which 40 were injured while working.11

Hot temperatures can impact a worker’s performance by reducing strength, accuracy, alertness, and mental capacity. Specific health problems include heat exhaustion, heat cramps, fainting, heat rash, and heat fatigue. In addition, hot weather can promote incidents from slick, sweaty palms or fogged safety glasses. Heat stress can be aggravated by the use of personal protective equipment that is commonly used in logging occupations. Heat stress can be reduced by the following interventions:
  • adopting work-rest cycles
  • improving air flow
  • using engineering controls (i.e., enclosed cabs)
  • providing cool rest areas and water
  • ensuring workers are acclimatized and in good physical condition

  • Examine the relationship between cold and vibration
  • Assess the impact of temperature extremes on the body (i.e., hypothermia, frostbite, immersion foot, heat exhaustion, and heat stroke)
  • Assess the impact of temperature extremes on injuries (i.e., back injuries)
  • Examine the role of hydration on heat and cold injuries
  • Investigate the role of sleep on heat and cold injuries
  • Train workers and supervisors about the risk factors for injury and illness when exposed to hot and cold environments
  • Develop training programs targeting prevention and mitigation of injury and disease from the heat and cold

Cohen BA. Injuries associated with cold and hot environments. In: Safety and Health in Agriculture, Forestry, and Fisheries (Langley RL, McLymore RL, Meggs WJ and Roberson GT eds). Rockville: Government Institutes, Inc., 1997. pp. 67-75.

Conway G, Husberg B. Cold-related nonfatal injuries in Alaska. Amer J Indus Med Suppl 1:39-41 (1999).

Rutgers Cooperative Extension. Preventing cold related illnesses in agricultural workers. Online: http://njaes.rutgers.edu/pubs/publication.asp?pid=FS677.

US EPA. A Guide to Heat Stress in Agriculture. EPA-750-b-92-001. Washington, DC: US Government Printing Office, 1993.

US NIOSH. Working in hot environments. DHHS 86-112. Cincinnati, OH: NIOSH, 1999.

US OSHA. Heat Stress. Online: http://www.osha.gov/SLTC/heatstress/index.html.


Work-related musculoskeletal disorders are common in the forest industry and can be quite costly. Existing scientific evidence identifies some work activities and awkward postures as significant contributors to the problem. The prevalence of back injuries and strains and sprains among forestland workers appears high in the Northwest. Tasks that are strenuous or require repetitive motion are of particular concern. The scientific field that evaluates and finds solutions to such problems is known as ergonomics. Ergonomics is the study of the interaction of people and their work environments, and requires a sound understanding of human factors engineering, work physiology, biomechanics, and mechanical and production engineering.

[NIOSH NORA: Lower Back Disorders, Musculoskeletal Disorders of the Upper Extremities]


Work-related musculoskeletal disorders are common and costly for all industries. The US Bureau of Labor Statistics shows that for each year from 1994 to 1998, musculoskeletal disorders were the second most commonly reported occupational illness (next to repeated trauma), constituting 13–14% of illnesses across all industries.12 Workers’ compensation costs may significantly underestimate the actual magnitude of these disorders. The causes for such disorders are complex. Existing scientific evidence identifies some work activities and awkward postures as significant contributors to the problem. A recent employer survey in Washington state showed that, in the agriculture industry (excluding forestry), those establishments reporting musculoskeletal disorders in the previous three years reported that 16.5% of injuries were to upper extremities and 15% to the back, while 61% were sudden onset injuries.13 While these numbers suggest that traumatic musculoskeletal injuries are more prevalent than chronic injuries, Washington state workers’ compensation claim statistics indicate that the logging industry is one of the top 25 industries in terms of non-traumatic soft tissue disorders of the neck, back and upper extremity between 1990 to 1998.14 This indicates that musculoskeletal disorders resulting from chronic injury are common among Washington loggers. Tasks that are either strenuous or require repetitive motion are of particular concern for forestland workers.

A Center-funded study looking at vibration and noise exposures in western Washington state found that forestry workers are overexposed to hand/arm and whole body vibration (according to criteria from the American Conference of Governmental Industrial Hygienists [ACGIH] and International Organization for Standardization [ISO]). ISO predicts the appearance of vascular symptoms in 10% of the monitored workers after 6 years, and 50% after 14 years of exposure at the measured hand/arm vibration levels. The ACGIH and ISO whole-body standards indicate that negative health effects are likely to occur at the levels of vibration measured at logging operations in Washington state.

  • Examine chronic conditions which contribute to, or are a precursor to an acute injury
  • Establish effective risk identification procedures for forestry jobs
  • Investigate methods to reduce chronic pain
  • Assess the effects of vibration levels on health
  • Identify the causes of musculoskeletal injuries
  • Investigate long-term injuries, such as carpal tunnel syndrome or arthritis from machinery operation
  • Evaluate the regulatory impacts of Washington state's new ergonomic rule
  • Investigate ergonomic issues in saw handling
  • Instruct workers on body mechanics and proper lifting, pulling, climbing, and jumping techniques
  • Focus training on prevention strategies
  • Conduct a back school similar to those provided to other professions, such as nursing home employees
  • Train workers to think ahead when faced with known hazards, such as uneven terrain, soft soil, falling trees and limbs

Anderson GBJ, Fine LJ, Silverstein BA. Musculoskeletal disorders. In: Occupational Health (Levy B, Wegma D, eds). Boston: Little, Brown and Co., 1995. pp. 455-489.

Silverstein B, Kalat J. Work-Related Disorders of the Back and Upper Extremity in Washington State, 1990-1997. Technical Report 40-2-2000. Olympia, WA: Department of Labor and Industries, 2000.

Silverstein B, Viikari-Juntura E, Kalat J. Work- Related Disorders of the Neck, Back, and Upper Extremity in Washington State, 1990- 1998. Technical Report 40-4a-2000. Olympia, WA: Department of Labor and Industries, 2000.

US NIOSH. Criteria for a Recommended Standard: Occupational Exposure of Hand-Arm Vibration. DHHS 89-106. Cincinnati, OH: NIOSH, 1989.

US NIOSH. Vibration Syndrome. Current Intelligence Bulletin 10. Washington, DC. pp. 83-110.

WISHA. Fitting the Job to the Worker: An Ergonomics Program Guideline (F417-110-000). Online: http://www.wa.gov/lni/wisha/veg/ vegtoc.htm.


Work in the forest results in frequent exposure to sun, plants, and chemicals. Contact with plants and some chemicals can produce allergic and irritant dermatitis, otherwise known as contact dermatitis. Contact dermatitis is the most important cause of occupational skin diseases nationally, and accounts for 13–14% of all reported occupational diseases. Sun exposure can cause additional irritation and over time can lead to skin cancer, the incidence of which has steadily increased over the last half century. Foresters and loggers’ chronic exposure to ultraviolet rays and their demographic characteristics (primarily white males) identifies them as a high risk group for skin cancer.

[NIOSH NORA: Allergic and Irritant Dermatitis]


Work in the forest results in frequent exposure to sun, plants, and chemicals. Each of these agents can cause skin injury and disease. The US Bureau of Labor Statistics shows that for each year from 1994 to 1998 skin disorders have been the second most commonly reported occupational illness, constituting 13 to 14% of reported illnesses.15 In Washington, agriculture (farming, fishing, and forestry) has the highest rate of occupational dermatitis among the major industrial sectors and it is estimated that this data under-represents the number of occupational skin disorders by more than four times.16

Contact with plants, and some chemicals, can produce allergic and irritant contact dermatitis. Susceptibility may be increased if there is exposure to broken skin (cuts and scrapes are common in forest work). Contact dermatitis is the most important cause of occupational skin disease across the nation, and accounts for 90% of all occupational dermatoses.17 Frequent skin contact with moisture, chemicals, friction, or dirt, all of which are common in forestland work, have been previously associated with an increased risk of hand eczema and contact dermatitis. Selected Northwest trees are known to cause dermatitis, particularly among workers who are exposed to airborne wood particles.18 There is additional evidence that some forest product workers who are exposed to liverwort (related to mosses) and lichens may develop irritant contact dermatitis.19 Allergic contact dermatitis is also caused by sensitizing agents and Northwest forests are abundant in two highly sensitizing plants: poison oak and poison ivy.

Sun exposure can cause additional irritation and skin cancer, the incidence of which has steadily increased over the last half century. Basal and squamous cell carcinomas are the most common malignancies, with an annual incidence of more than 600,000 cases in the US.20 These nonmelanoma skin cancers are directly related to chronic overexposure to ultra-violet rays, which makes these cancers easily preventable if workers avoid direct sun exposure and wear protection.21 Melanoma represents only about 5% of all skin cancers in the United States, but it accounts for about 75% of all skin cancer deaths, about 6,900 deaths per year.22 In the United States, the reported incidence of melanoma from 1973 to 1991 for white males rose 124%; a rate of increase that leads all other cancers.23 The increased risk for skin cancer among people who work outdoors is well documented for certain occupations. Although there are few studies specific to forest workers, forest-land work encompasses known risk factors, which place foresters and loggers at high risk for cancer.

  • Assess exposure to hydrocarbons (oil, gasoline, grease) and its relationship to dermal conditions and cancers
  • Identify the prevalence and causes of dermatitis in forestland work to improve exposure assessment and diagnostic methods
  • Develop and test efficacy of barrier lotions for poison oak and poison ivy
  • Investigate the long-term effects of chemical exposure on respiratory and dermal systems
  • Develop cost-effective screening programs
  • Develop training that emphasizes hazard identification, personal predisposition, avoidance, protective clothing, barrier creams and hygiene
  • Provide health care professionals with training in occupational-related skin disorder diagnosis
  • Conduct physician training in cutaneous malignancies, including basal and squamous cell carcinomas, melanoma, and their precursor lesions

Arndt KA, Bigby M, Coopman SA. Skin disorders. In: Occupational Health and Recognizing and Preventing Work-Related Disease. (Levy BS, Wegman DH, eds). Boston: Little, Brown, and Co., 1995. pp. 491–506.

Gloster H, Brodland D. The epidemiology of skin cancer. Dermatol Surg 22:217-226 (1996).

Kaufman JD, et al. Occupational skin diseases in Washington State, 1989 through 1993: using workers’ compensation data to identify cutaneous hazards. Am J Public Health 88: 1047-51 (1998).

Reding DJ, Rauska ML, Lappe KA, Fischer W. Cancer education interventions for rural populations. Cancer Practice 2:353–358 (1994).

Sama S, Bushley A, Cohen M, Cotey M, Park B, Kaufman J. Work-related skin disorders in Washington State, 1993–1997. Olympia, WA: Department of Labor and Industries, 1998. Online: http://www.wa.gov/lni/sharp/ derm93_7.pdf.

National Cancer Institute. Cancer Information Online: http://www.nci.nih.gov/cancerinfo/ index.html.


Injury takes a huge toll in many US workplaces, including the forestry industry. Multiple factors contribute to traumatic injuries, such as the characteristics of the workforce, job design, work organization, economics, and other social factors. Fatalities and nonfatal traumatic injuries resulting from human contact with machinery, equipment, trees, and parts of trees are common in forestry and logging. Overexertion, stress, fatigue, lack of training, and operator attitude can all serve as precursors for injuries.

[NIOSH NORA: Traumatic Injuries]


The forest resources industry is one of the most hazardous in the United States, the fatality rate of loggers in 1997 was approximately 27 times the national average (128 vs. 5 per 100,000). Nationally, nonfatal injuries between 1992 and 1996 declined from 4,537 injuries per year to 2,136 injuries per year, yet rates are still high and injuries severe, resulting in a median number of 11 days away from work.24 A study of logging fatalities in Washington state indicated that employees of smaller logging firms had a higher risk for mortality.25 This trend for small businesses is apparent on a national level, with logging in the top five of all small businesses with high risk for injury or death.26

Based on Washington state workers’ compensation claims data, the rate of nonfatal lost time injuries for loggers (13.5 per 100 full time equivalents [FTE]) is more than 3.5 times that of all industries combined (3.8 per 100 FTE).27 In Oregon, the average fatality rate by industry for 1993 through 1997 finds agriculture, forestry and fishing as having one of the highest fatality rates (19.0 per 100,000, just below construction at 19.4 per 100,000).28

In a review of the Alaska Trauma Registry for 1991 through 1995, logging had the highest average annual injury rate (2.5 for every 100 workers) of all occupations in Alaska.29 The types of injuries sustained by those individuals working in forestlands range from frequent minor injuries to very severe incidents. A review of patients examined at Harborview Medical Center in Seattle found that of 51 logging-injured patients, 67% were injured by falling or rolling trees and 16% were chain saw-related. Of these patients, 43% experienced serious head injuries (22% had major brain injury) and 30% were found to have spinal injuries (50% having neurologic deficit). Chest and extremity injuries were also common and two thirds of the patients had two or more parts of their bodies which were severely injured. In a six-month follow-up on 43 of these patients, 58% were considered permanently disabled.30

Oregon’s disabling claims indicated loggers most frequently experienced sprains and strains, struck-bys and back injuries.31 Likewise, in a review of nonfatal injuries in Alaska, struck-bys and falls led in causes of all severe injuries with fractured bone being the most common injury and most injuries impacting the lower extremities.32 In British Columbia from 1991 to 1995, serious claims in logging included strains (37%), bruises (21%), cuts (14%), and fractures and dislocations (11%).33

Project participants identified traumatic injuries as one of the top priorities for research. Concerns included both fatal and nonfatal injuries, with an emphasis on eye injuries. Traumatic incidents were attributed to struck-by injuries, slips, trips and falls. Overexertion and fatigue were also noted as predispositions to forestry-related incidents. Participants felt that research should focus on leading causes and high-risk groups and effective interventions may require collaboration among different academic disciplines and cooperation among many organizations.

  • Examine the relationship between harvesting system and injury
  • Explore relationship between fatigue and injury rate
  • Conduct epidemiological analysis of injuries to determine the leading causes and high risk groups
  • Develop reliable and valid systems to measure extent of injuries, which includes measuring the hazards
  • Conduct a quality state-by-state study of serious injury and fatality causes
  • Investigate injury timing (within a day and week) by job category
  • Describe injuries in nonfatal cases as most injury data is based on fatality data
  • Develop effective interventions through collaboration among organizations
  • Provide training in hazard recognition (recognizing snags, widowmakers [hung-up limbs and trees], etc.)
  • Instruct workers on techniques for falling with less potential for injury
  • Provide employees with medical information documenting the serious nature of chain saw cuts and when to seek medical aid

Holman R, Olsewski A, Maier R. The epidemiology of logging injuries in the Northwest. J of Trauma 27(9):1044-1050 (1987).

Husberg B, Conway G, More M, Johnson M. Surveillance for nonfatal work-related injuries in Alaska, 1991-1995. Amer J Indust Med 34:493-498 (1998).

Oregon Department of Consumer and Business Services. Logging: Disabling Claims and Inspections: Calendar years 1991 through 1995. September, 1997.

Sygnatur EF. Logging is perilous work. Compensation and Working Conditions. Winter: 3-9 (1998).

Tippens R, Landly R. Epidemiology of forestry injuries and illnesses. In: Safety and Health in Agriculture, Forestry, and Fisheries (Langley RL, McLymore RL, Meggs WJ and Roberson GT eds.). Rockville: Government Institutes, Inc., 1997. pp. 59-65.

US NIOSH. Preventing Injuries and Deaths of Loggers. DHHS 95-101. Cincinnati, OH: NIOSH, 1995.

Workers’ Compensation Board of British Columbia. Logging industry focus report. November, 1996.

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