During the winter months many municipal employees face an additional occupational hazard, exposure to the cold. Some health problems can arise including frostbite and hypothermia. This risk alert is designed to provide readers with basic information on how to prevent cold-related illnesses.
THE COLD ENVIRONMENT
How the body responds to cold. An individual gains body heat from food and muscular work, and loses it through convection, conduction, radiation and sweating to maintain a constant body temperature of approximately 98.6 degrees Fahrenheit. The body’s first response to a cold environment is constriction of the blood vessels of the skin, that reduces heat loss from the surface of the skin by decreasing peripheral blood flow, and/or shivering, that generates heat by increasing the body’s metabolic rate.
Environmental conditions that cause cold-related stresses are low temperature, cool high winds, dampness and cold water. Wind chill, temperature and wind velocity) are important factors to evaluate when working outside. For example, when the actual air temperature of the wind is 40 degrees F and its velocity is 35 mph, the exposed skin would perceive these conditions as if the equivalent still air temperature was 11 degrees F. A dangerous situation of rapid heat loss may arise for any individual exposed to high winds and cold temperatures.
OTHER MAJOR RISK FACTORS FOR COLD-RELATED STRESSES
In addition to the cold environment, other major risk factors contributing to cold-related stresses include:
- Inadequate clothing or wet clothing, the actual effects of cold on the body depends on how well the skin is insulated from the environment.
- Drug use or certain medications may inhibit the body’s response to cold or impair judgement; examples include beta blockers, alcohol and cigarettes.
- A cold or other disease, such as diabetes, atherosclerosis and hypothyroidism may increase risk.
- Gender; male death rates due to cold exposure are greater than rates for females; perhaps because of inherent risk-taking activities, body fat composition or other physiological differences.
- Susceptibility increases with age.
- Exhaustion or immobilization, especially through injury or entrapment.
HARMFUL EFFECTS OF COLD
Common harmful effects of cold include frostbite and hypothermia.
Frostbite occurs when skin tissue actually freezes and cell damage results. The freezing point of skin is approximately 30 degrees Fahrenheit and wind chill can be a significant factor in accelerating the process. Fingers, toes, cheeks, nose and ears are primarily affected. The symptoms of frostbite include an uncomfortable sensation of coldness; there may also be a tingling, stinging or aching feeling followed by numbness. Initially the frostbitten area appears white and is cold to the touch. This is followed by heat, redness and swelling. Occasionally a victim may not be aware of the frostbite.
Tissue damage can be mild and reversible or severe, resulting in scarring and tissue death. Amputation or loss of function can be an unfortunate result. First aid includes treating affected areas with warm water at 102 to 110 degrees Fahrenheit. Be careful to avoid rubbing frostbitten areas because this can lead to greater tissue injury. If there is a chance for refreezing, do not rewarm the affected areas.
Hypothermia is the progressive loss of body heat with prolonged exposure to cold. Body heat loss is accelerated more rapidly when a person is wet because of sweat or working in a damp environment. Most cases of hypothermia develop in air temperatures between 30 and 50 degrees Fahrenheit, but significant hypothermia can occur with air temperatures as high as 65 degrees (particularly when clothing is wet), or in the water at 72 degrees.
The first symptoms of hypothermia are uncontrollable shivering and feeling of cold. As the body’s temperature continues to drop, an individual can become confused, careless and disoriented. At this point a person may make little or no effort to avoid further exposure to the cold. For those working around machinery, accidental injury is an additional risk. When the core body temperature falls below 86 degrees, the body’s adaptive mechanisms for reducing heat loss become ineffective and death can occur.
PREVENTING COLD-RELATED DISORDERS
The following recommendations may help to reduce the number of cold-related disorders that municipal employees experience during winter months.
Personal Protective Clothing
- Dress appropriately. Wear at least three layers, an outer layer to break the wind and allow some ventilation; a middle layer of wool, down or synthetic material to absorb sweat and retain insulating properties when wet; and an inner layer of cotton or synthetic weave to allow ventilation and escape of perspiration.
- Layer clothing to create air pockets that help retain body heat. Layering also makes adapting to changes in weather and level of physical exertion easier.
- Keep available a change of clothing if work garments become wet.
- Pay special attention to protecting feet, hands, head and face. Keep the head covered (up to 40 percent of body heat can be lost when the head is exposed). Fingers and hands lose their dexterity at temperatures below 59 degrees.
- Wear footgear that protects against cold and dampness. Footgear should be insulated and fit comfortably when socks are layered.
- Avoid wearing dirty or greasy clothing because such garments have poor insulating qualities.
Safe Work Practices
- Allow individuals to set their own pace and take extra work breaks when needed.
- Avoid activities, whenever possible, that lead to heavy perspiration.
- Shift as many outdoor activities to the inside as feasible and when working outside, select the warmest hours of the day.
- Minimize activities that reduce circulation, such as sitting or standing in a cold environment for prolonged periods of time.
- Keep energy levels up and prevent dehydration by consuming warm, sweet, caffeine-free, nonalcoholic drinks and soup.
- Allow a period of adjustment to the cold before embarking on a full work schedule.
- Avoid working alone in very cold weather, use a buddy system.
- Seek warm shelter immediately following these symptoms, heavy shivering, an uncomfortable sensation of coldness, severe fatigue, drowsiness or euphoria.
WORKER HEALTH EDUCATION
- Older workers, or those with certain medical problems, need to be extra alert about the effects of cold stress. Check with a doctor about special needs and precautions.
- Avoid using alcohol or drugs, which may impair judgment while working in a cold environment. Hypothermia commonly occurs in association with alcohol abuse. In addition to its effects on judgment, alcohol increases heat loss through vasodilation and may impair shivering.
- Educate new workers on the hazards of working in a cold environment.
- Prevent chapped skin by the frequent use of protective lotions.
Preventing Cold-Related Illnesses was written by Gary Cauthen, OMAG Loss Control Specialist. You may contact the author at: firstname.lastname@example.org. The information in this bulletin is intended solely for general informational purposes and should not be construed as or used as a substitute for legal advice or legal opinion with respect to specific situations, since such advice requires an evaluation of precise factual circumstances by an attorney. The Oklahoma Municipal Assurance Group does not represent or endorse any group, site or product mentioned in the article. This publication supersedes the Risk Alert entitled Hazards of Working in Cold Weather published in February, 1994