Avoiding Heat Stress: Guidelines for Pesticide Workers

Avoiding Heat Stress

Now that PPE has been discussed, it is time to examine heat stress and its relation to PPE. Heat stress is an illness that occurs when the body builds up more heat than it can cope with. Heat stress is not caused by exposure to pesticides, but may affect pesticide handlers who are working in hot conditions. Wearing PPE, clothing and devices that protect the body from contact with pesticides can increase the risk of heat stress by limiting the body's ability to naturally cool itself.

Several factors work together to cause heat stress. Before beginning a pesticide handling task, think about whether any of these factors are likely to be a problem. Consider making adjustments in the task itself or in the workplace conditions, including:

• heat factors - temperature, humidity, air movement, and sunlight;
• workload - the amount of effort a task takes;
• personal protective equipment (PPE);
• water drinking, and scheduling.

Heat and Workload Factors

Heat and Workload: High temperatures, high humidity, and sunlight increase the likelihood of heat stress. Air movement, from wind or fans, should provide cooling. Because physical work causes the body to produce more heat, a person is more likely to develop heat stress while working upright, such as lifting or carrying heavy containers, than someone sitting while driving a vehicle or flying an aircraft.

Cooling Systems and Shade

Cooling Systems and Shade: When indoors use fans or ventilation system, and shade whenever possible outdoors. A work area or vehicle can sometimes be shaded with a tarp, canopy, awning, or provided with fans or air conditioners. Consider wearing cooling vests - garments with ice or frozen gel inserts that help keep the body cool.

Adjusting to Heat and Workload

Allow Time to Adjust - Allow time to adjust to the heat and workload. People who have become used to working in the heat are less likely to be affected by heat stress. To adjust to a hot working environment, allow two hours of light duty per day in the heat for several days in a row; then gradually increase the work period and the workload for the next several days. An adjustment period of at least seven days is recommended. If warm weather occurs gradually, handlers may adjust naturally by working in the increasing temperatures.

Level of PPE for Pesticide Use

Level of PPE:

Select a level of PPE that is appropriate for the pesticide being used. The pesticide label will indicate the minimum PPE to be used. Use personal experience and PPE selection guides to help decide whether more protection is needed. Do not over-protect if heat stress is a concern, but wear at least the minimum required PPE. Generally, the more protective the equipment, the more it adds to the heat load.

• Select Coolest Possible PPE - Choose PPE that is designed to be as cool as possible or that provides a cooling effect, such as a powered air-purifying respirator or, when appropriate, back-vented coveralls. Whenever practical, choose coveralls 48that allow air to pass through them. Woven fabrics (cotton, or cotton-polyester blends) allow air to pass through fairly easily. Rubber or plastic fabrics and fabric with chemical-resistant barrier layers allow almost no air to pass through. Non- woven polyolefin (Tyvek®) fabrics allow little air to pass through. Depending on how they are constructed, non-woven polypropylene and polyester/wood pulp fabrics vary in their resistance to airflow.

Drinking Water Intake

Drinking Water Intake:

Evaporation of sweat cools the body. Under the conditions that lead to heat stress, the body produces a large amount of sweat. To help maintain a normal body temperature, the water lost in sweat must be replaced.

• Drink Enough Water - During periods of high temperature, drink plenty of water before, during, and after work. Do not rely on thirst. A person can lose a dangerous amount of water before feeling thirsty, and the feeling of thirst may stop long before fluids are replaced.
• Maintain Weight - Be sure to keep body weight fairly constant. All weight lost due to perspiration should be regained every day. People working in heat stress conditions should weigh themselves before work every day and keep weight constant by drinking plenty of water.

Scheduling to Avoid Heat Stress

Scheduling:

When the combination of temperature, sunlight, humidity, workload, and PPE is likely to lead to overheating, use scheduling to avoid heat stress.

• Work During the Coolest Times - Schedule tasks requiring the heaviest workload or the most PPE during the coolest part of the day.
• Use work/rest cycles - When the possibility of heat stress is high, schedule frequent breaks to allow the body to cool. Consider using a work/rest cycle guide to decide how long to work before taking a break.

Remember that people differ in their ability to work in hot conditions. Most work/rest cycle guides are based on an average of many people who are adjusted to the heat and the workload. Workers who have not had time to adjust should work less time than the guide indicates.

When using recommended work/rest cycles, continue to be alert for possible heat stress problems. Anyone who gets dangerously hot should stop work immediately and cool down. If necessary, shorten the time between breaks.

Signs and Symptoms of Heat Stress

49Signs and Symptoms of Heat Stress:

Heat stress, even in mild forms, makes people feel ill and impairs their ability to work effectively. They may get tired quickly, feel weak, be less alert, and be less able to use good judgment. Severe heat stress (heat stroke) is a serious illness. Unless victims are cooled quickly, they can die. Severe heat stress is fatal to more than 10 percent of its victims, even young, healthy adults. Victims may remain sensitive to heat for months and be unable to return to the same work.

Learn the signs and symptoms of heat stress and take immediate action to cool down if they appear. Signs and symptoms may include:

• fatigue (exhaustion, muscle weakness);
• headache, nausea, and chills;
• dizziness and fainting;
• loss of coordination;
• severe thirst and dry mouth;
• altered behavior (confusion, slurred speech, quarrelsome or irrational attitude).

Heat Cramps

Heat cramps can be painful. These are muscle spasms in the legs, arms, and stomach caused by loss of body salts through heavy sweating. To relieve cramps, drink cool water or sports drinks. Stretching or massaging muscles may temporarily relieve cramps. If there is a chance that stomach cramps are being caused by pesticides rather than the bodies loss of salt, get medical help right away.

First Aid for Heat Stress

First Aid for Heat Stress:

It is not easy to tell the difference between illness brought on by heat stress and that of pesticide poisoning. The signs and symptoms are similar. Don't waste time trying to decide what's causing the illness. Get medical help right away.

First Aid Steps

First aid:

• Get the victim into a shaded or cool area;
• Cool victim as rapidly as possible by sponging or splashing skin, especially face, neck, hands, and forearms, with cool water or, when possible, immersing in cool water;
• Carefully remove all PPE and any other clothing that may be making the victim hot;
• If the victim is conscious have them drink as much cool water as possible;
• Keep the victim quiet until help arrives.

Severe heat stress (heat stroke) is a medical emergency! Cool victim immediately! Brain Damage and death can result if treatment is delayed.

Multiple Chemical Sensitivity (MCS)

50Multiple Chemical Sensitivity (MCS) Multiple Chemical Sensitivity (MCS) is one of several names used by some to explain the wide array of physical and psychological symptoms expresses by those who are, or claim to be, adversely affected by chemicals. These symptoms are extremely diverse and include headaches, fatigue, difficulty concentrating and depression. A few other terms used to describe these symptoms include:

• environmental illness;
• total allergy syndrome ;
• 20th century disease.

Often, those who believe they have MCS say their symptoms are caused by exposure to certain foods and chemicals, including low levels of household chemicals and pesticides. However, decades of medical and scientific study have failed to find evidence that MCS exists. In fact, the American Medical Association Council on Scientific Affairs, the American College of Physicians, and the American Academy of Allergy, Asthma and Immunology all reject MCS as a clinical disease and discourage its use as a diagnosis.

The symptoms ascribed to MCS can be caused by a number of diverse medical problems. People may have medical problems not yet diagnosed, suffer from allergies, experience a psychological reaction to an unpleasant odor, or have stress-related problems.

People who believe they have MCS may truly be suffering from some other physical or psychological ailment. It is understandable that people seek an explanation or name to describe their condition. As a result, the concept of MCS has spread within the popular culture, despite overwhelming medical evidence that MCS is not a clinical disease.

Indoor Air Quality

51Indoor Air Quality All applicators should have an awareness of indoor air pollution. Indoor air quality is a relatively new environmental issue. Today most Americans spend up to 90% of their time indoors, that is inside their home, office, stores, and other spaces.

Indoor air pollutants can cause long and short term health effects, especially when concentrations build up over time.

There are many potential sources of indoor air pollution in any home, apartment, office building, warehouse, restaurant, store, etc .; and yes, pesticide application and storage are on the list. Applicators should be aware that what they spray in a house, apartment, office building, warehouse, restaurant, store, etc., can affect indoor air quality.

One reason for indoor air problems is inadequate ventilation. If too little outdoor air enters a home, apartment, office building, store, etc., pollutants can build up causing discomfort or health problems. New home building techniques compound this problem because they are built "leak-free", that is they are designed for energy efficiency and minimize the amount of outside air that can "leak" in.

A number of well identified illnesses, such as Legionnaire's disease, asthma, hypersensitivity pneumonitis, and humidifier fever, have been directly traced to specific building problems. These are called building-related illnesses. Most of these diseases can be treated; nevertheless some can pose serious risk to sensitive individuals.

Pest Control Operators and Indoor Air Problems

What can pest control operators do to alleviate indoor air problems from pest control? There are two basic strategies; they are Source Control and Ventilation.

• Source Control - This is usually the most effective way to improve indoor air quality. Be Aware of Your Surroundings. If indoor air is a concern in a home, apartment, office building, warehouses, restaurant, store, etc., an applicator should limit the amount of indoor spraying. Baits, monitoring traps, gels, etc., should be relied upon more in these situations.
• Ventilation - This is another approach to lowering the concentrations of indoor air pollutants. The idea is to increase the amount of outside air entering the structure. One way of accomplishing this while conducting pest control is to open windows and doors, and by turning on bathroom and kitchen exhaust fans if they are vented to the outside. In both cases they will lower indoor air pollution by removing pesticide contaminants from the air.

It is particularly important to take as many precautions as possible when doing pest control. Pest control is a short-term activity that can generate high levels of "pollution" in a short period of time. Again, know the environment, take into consideration children's rooms, the elderly, people with allergies, etc. These people may be more sensitive to pesticides and pesticide odors. Talk with clients and look around and behind objects before spraying; and notice if the house is closed-up tight. Be observant and use senses (eyes, ears, noise) when examining a particular place.

52