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Summer Hazards

Summer Hazards for Outdoor Workers

By Ashley Seitz, summer intern at Public Entity Risk Institute

Though warm summer months usually lead to thoughts of merriment and outdoor activity, employees who work outdoors must be well informed about possible injuries and illnesses related to outdoor exposure.  The risks of Heat-Related Illnesses, Lightning Strikes, and Insect-Borne Diseases such as Lyme Disease and the West Nile Virus all reach their peak during the summer.  Local governments often employ workers who spend much of their summer working time outdoors.  Public works, street and sidewalk repair, refuse collection and parks and recreation are just a few of the local government operations that expose public employees to increased risk from summer hazards.  Local governments whose employees work outside during summer months can reduce these risks by taking some simple and low cost precautionary measures, and making their employees aware of these potential hazards and how to minimize their risk.

Heat-Related Illnesses

Heat-related illnesses are a hazard whenever a job requires long periods of outdoor exposure in the summer heat.  Heat stroke, heat exhaustion, heat cramps, heat rashes, and heat syncope are all variations of heat related illness that can affect outdoor workers.  Heat stroke is a medical emergency that can lead to death without treatment.  Heat exhaustion is very serious because, if left untreated, it can progress to heat stroke.  Heat syncope, which is heat-related dizziness and fainting, can also be very serious for workers who work in places where they may suffer a physical injury if they become dizzy or pass out. Heat-related illnesses therefore pose a risk of serious physical injury to outdoor workers, and deserve serious consideration as outdoor temperatures climb.

Heat-related illnesses occur when internal body temperature increases and the body cannot cool itself effectively.  Humidity and lack of air circulation reduce the evaporation of sweat, which is the body’s natural cooling mechanism.  High temperatures, humidity, sunlight, and physical labor increase the likelihood of heat-related illness.  Workers who are older, obese, dehydrated, sleep deprived, alcohol and drug users, users of certain medications, pregnant, using personal protective equipment such as respirators and body suits, or have certain pre-existing medical conditions are all more susceptible to heat related illnesses. Even without serious physical illness, intense heat increases the chance that employees will lose their concentration, become fatigued and irritable, and suffer a work related injury.

Sudden extended periods of exposure to heat are more likely to cause heat-related illnesses if the worker has not had a chance to acclimate him or herself to the new environment.  The acclimation process, which slowly increases tolerance to heat exposure, can take from a few days to a few weeks.

To avoid heat related illness, OSHA recommends that workers acclimate themselves to the heat; perform the heaviest work during the coolest part of the day; limit exposure to heat by taking frequent short breaks in cooler areas; drink plenty of cool water – one small cup every 15 to 20 minutes; wear light, loose fitting clothing that keeps the body cool but prevents sunburn; avoid eating large meals before working in hot environments; avoid caffeine and alcoholic beverages, which make the body lose water; and work in pairs, so employees can watch out for the well being of each other.

Employees who take medication, including over the counter medications and dietary supplements, should check with their physicians to determine whether those medications may contribute to heat-related illness.  The Centers for Disease Control and Prevention says that "the risk for heat-related illness and death may increase among people using the following drugs: (1) psychotropics, which affect psychic function, behavior, or experience (e.g. haloperidol or chlorpromazine); (2) medications for Parkinson’s disease, because they can inhibit perspiration; and (3) tranquilizers such as phenothiazines, butyrophenones, and thiozanthenes."[1]  The National Institute for Occupational Safety and Health recommends that people who take blood pressure control, diuretics, or water pills ask their physicians whether their medications may cause side effects during excessive heat exposure.[2]  And questions have been raised about the possibility that ehpedra or ephedrine, an ingredient in some dietary supplements and over the counter nasal decongestants, may increase the risks of succombing to a heat-related illness.[3]

Employers should train their outdoor employees each year about the signs and symptoms of heat related illnesses and how to respond, schedule work to provide breaks from the heat, provide easy access to plenty of cool water for employees working in the heat, ensure that their employees have the means to summon help if necessary, and provide employees with other means of cooling off – such as misting bottles.  Although employers usually cannot ask their employees about medications they take, they should warn employees of the potential risks of certain medications in a hot work environment, and encourage them to talk to their physician.

Heat stroke is a medical emergency: a life threatening heat illness associated with working under extremely hot and humid conditions.  Victims of heat stroke have lost ability to control body temperature.  Warning signs of heat stroke include:

  • high body temperatures, 104 degrees Fahrenheit or over
  • hot and dry skin that appears bluish or red
  • no sweating
  • rapid heart rate
  • dizziness
  • shivering
  • nausea
  • irritability
  • severe headaches
  • mental confusion
  • convulsions
  • unconsciousness, which may result in coma or death

When heat stroke is suspected, OSHA[4] (the Occupational Safety and Health Administration) recommends that the employer or co-workers summon emergency medical help (911 or an ambulance) immediately; move the victim to a cool shaded place and place the victim on his or her back, unless there is vomiting, in which case the victim should be placed on his or her side; remove outer clothing; have the victim drink cool water (a small cup every 15 minutes) if he or she is alert and not nauseous; cool the victim by wetting the skin with water and fanning; and apply cold packs to skin – especially under the arm pits and the groin area.  If cool (not cold) water is available, the victim can be immersed in it to lower body temperature.  The victim should not be left alone at any time.

Heat exhaustion occurs when there is a decrease in body water content or blood volume.  This can happen over several days, it the worker loses more fluids through sweat than is replaced through consumption.  Heat exhaustion is very serious, because left untreated it can progress to heat stroke.

  • Heat exhaustion victims show signs of:
  • heavy sweating
  • clammy, flushed or pale skin
  • weakness
  • dizziness
  • nausea
  • rapid/shallow breathing
  • headaches
  • vomiting
  • fainting

If heat exhaustion is suspected, OSHA recommends that the victim be moved to a cool area; placed on his or her back with legs raised about six to eight inches - unless there is vomiting, in which case the victim should be placed on his or her side; co-workers should help loosen and remove heavy outer clothing to cool off the body; encouraged to drink some cool water – a small cup every 15 minutes – if not nauseous; fanned and cooled with water mist or moist cloths.  If there is any question about whether the employee has heat stroke or if the employee does not improve within a few minutes, call emergency medical help (911 or an ambulance) immediately.

Heat syncope is dizziness or fainting, caused by standing still for an extended period in a hot environment.  Blood pools in the skin and legs, decreasing blood flow to the brain.  Heat syncope is different from heat exhaustion and stroke, because there are no warning symptoms, and it is not as serious a medical condition as either heat exhaustion or heat stroke.  However, it can be very serious for employees who work in a position of risk, where fainting or dizziness can cause the employee to fall and sustain a serious physical injury.

To treat heat syncope, move the victim to a cooler environment.  Heat syncope can be prevented by acclimation to the hot environment, avoiding stationary activities and observing the other precautions recommended for avoiding heat-related illness.[5]

Heat cramps are painful cramps or spasms in the legs, arms or abdomen, accompanied by excessive sweating, either during or after exposure to heat.  Heat cramps often result from temporary fluid and salt imbalance caused by intense sweating while performing hard physical work in a hot environment.

To treat heat cramps, move the employee to a cool place, massage the area or muscle, and encourage the employee to take sips of salt water (one teaspoon of salt to a quart of cool water) or another fluid that replaces electrolytes.[6]

Heat rash occurs when skin remains damp because of unevaporated sweat, causing red bumps on skin because of the built-up sweat underneath.  Heat rash can cause damage to the skin and sweat glands, the ruptured bumps can become infected, and in extreme cases can progress to heat exhaustion.  After the skin heals, sweat production may be compromised, and not return to normal for another four to six weeks. 

Lightning Strikes

Summer also increases the likelihood of thunderstorms the risk of injuries to outdoor employees from lightning strikes.  An average of 73 people per year have been killed by lightning strikes over the past 30 years, and another 300 people are injured every year.  Though it doesn’t seem very likely, lightning has the second-highest death toll per year of all natural disasters, behind flooding. For those who survive, being struck by lightning can cause debilitating and ongoing health problems.

Lightning strikes have two components: the visible flash from the clouds to the ground, and a subsequent current that travels along the ground.  The current that travels along the ground causes the most injuries.  High winds, rain, and dark clouds are all warning signs of thunderstorms, and therefore of potential lightning strikes.  Lightning may pose a threat even if it does not appear to be close.  If the time delay between seeing lightning and hearing thunder is less than 30 seconds, then the National Oceanic and Atmospheric Administration says there is danger of being struck by lightning.

During thunderstorm season, outdoor employees and their employers should carefully monitor weather forecasts.  Employers should adjust activities as necessary to avoid their employees being stranded in a dangerous area during thunderstorms.  Employers should also establish appropriate emergency plans for their employees in the event the employees are unexpectedly caught in a thunderstorm, and employees should be trained about those plans, and how to seek shelter in an emergency.  Outdoor employees should work in pairs or teams, and should always have a means of summoning emergency help.    

Employees should avoid the following places during a thunderstorm:

  • open fields
  • isolated trees
  • unprotected gazebos
  • rain/picnic shelters
  • baseball dugouts
  • communications towers
  • flagpoles/light poles
  • bleachers
  • metal fences
  • convertibles
  • golf carts
  • water sources

Lightning usually hits the tallest object in its area, so employees who cannot find indoor shelter when thunderstorms approach should be trained to find a low area.  If caught unexpectedly in an exposed area, employees can crouch down to reduce risk of being struck by lightning.  The crouching position recommended by NOAA is to rest on the balls of the feet, similar to a catcher’s position in baseball, to minimize the ability for the body to ground electricity.  Employees must know to never hide under trees for shelter, and to stay at least six feet away from any tall object.  If trapped in a boat, employees should know to crouch down in the center of the boat, stay away from metal equipment, and to not go in the water under any circumstances.

According to the NOAA, no structure is absolutely safe during a thunderstorm, but large enclosed structures are usually safer than small, open structures.  But when inside, employees should avoid using the telephone, showering, washing dishes or hands, or touching metal doors, window frames, wiring, and plumbing.  Employees should not lean against walls or floors, since they may contain metal.  Generally, an enclosed metal vehicle provides good protection from lightning when the windows are closed.

The 30-minute rule usually applies to thunderstorms: wait 30 minutes after the last sound of thunder before going outside.  More than 50% of the deaths attributed to lightning occur after the thunderstorm has passed.  Lightning strikes can even occur when the skies are blue.

Lightning strikes result in deep burns at point of entry and exit, usually the head, neck or shoulders, and feet, but injuries from being thrown and cardiac and cardiopulmonary arrest are the usual causes of injury and death.  Lightning victims are not electrified, and rescuers can safely administer first aid.  NOAA says that 90% of all lightning victims survive the strike, especially with timely medical treatment.  Emergency Medical Assistance (911 or ambulance) should be called at once.  If the victim has no pulse, cardiopulmonary resuscitation (CPR) can be administered or an automatic external defibrillator may be used until emergency medical assistance arrives.

Insect-Borne Diseases

Diseases carried by insects, such as mosquitoes and ticks, pose some summertime hazard even though infection is unlikely from any individual insect bite.  Lyme Disease and the West Nile Virus are two insect-borne illnesses that have received a great deal of attention in recent years.  However, both diseases are regional at this time, and can be prevented through similar precautions.
Lyme Disease

Lyme disease, a tick-borne illness that affected more than 16,000 people in 1998, is on the rise for outdoor workers.  New Jersey has the highest percentage of infected ticks; about 25 to 50 percent of their deer tick population is infected with Lyme Disease.  The highest risk areas for infection with Lyme disease include the states from Massachusetts to Maryland, the north-central region including Wisconsin and Minnesota, and northern California.  The remaining states have minimal risk.

Lyme Disease is typically transmitted by the deer tick (or black-legged tick), which is found in grassy areas, open fields, and woods that have shrubby growth.  There are two stages of potentially dangerous ticks: the nymphs and the adults.  Nymphs have translucent bodies with a dark head, and are about the size of a poppy seed.  Adults are all black, and are about the size of a sesame seed.  Nymphs are most active from May to June, and adults are active all winter long, as long as the temperature is above freezing.  Most Lyme Disease infections are transmitted by bites from the nymph stage deer tick.  

To transmit Lyme Disease, it is believed that a tick has must be attached to a human for at least 12 hours, so routine checks immediately after outdoor exposure help prevent transmission.  Ticks are most likely to be found in hidden and hairy areas of the body such as armpits, groin, and scalp.  They should be removed as soon as possible with a pair of needle nose tweezers, preferably bent needle nose tweezers.  Grasp the tick by the head, close to the skin, and pull it up and out, slowly and firmly.[7]  The NASD recommends against using vaseline, matches, or nail polish, because the trauma to the tick makes transmission of the disease more likely.  The area should then be sterilized and the tick should be saved for later identification by a doctor to ensure that Lyme Disease was not transmitted.   

The symptoms of Lyme Disease include:

  • headache
  • flu-like symptoms
  • the “Bull’s-eye” rash (greater than two inches in diameter)
  • swelling and pain in the joints

About 70% of those infected with Lyme Disease develop the rash within two days to four weeks, but if left untreated the symptoms can worsen to chronic inflammatory arthritis, chronic muscle pain, heart disease, and neurological disorders, so a blood test and doctor’s care should be sought as soon as possible.  Lyme Disease is curable with antibiotics when caught early.

To reduce exposure to Lyme Disease, workers should:

  • Avoid tall grass and shrubs
  • Wear long pants, sleeves, closed-toe shoes, and a hat
  • Wear light colored clothing to make tick identification easier
  • Shower and wash clothing at high temperatures to kill any possible ticks
  • Widen trails through woods and always walk away from the vegetation
  • Remove brush pile habitats
  • Use effective bug repellents on shoes, socks and pants, allowing it to dry.  (Some people may be sensitive to and should avoid preparations containing DEET)
  • Apply insecticides (preferably granular) to areas that may harbor ticks[8]

The West Nile Virus originated in Africa but has now permanently established itself in the United States, primarily in the Eastern states.  No spread of West Nile Virus activity beyond Connecticut, New York, New Jersey, Maryland, and Virginia has been detected.  Transmitted to humans only by infected mosquitoes, the West Nile Virus travels through the blood and can occasionally cause encephalitis, an inflammation of the brain, and problems with the central nervous system.  The incubation period is three to fifteen days.

Infection with West Nile from an individual mosquito bite is unlikely, because only 1% of all mosquitoes carry the disease.  Only about 1% of the people infected with West Nile Virus will develop serious illness, and of the 1% who develop the serious illness, only about 3% to 15% die.  The people with the greatest risk of developing severe illness are usually 50 years of age or older.

The symptoms of a serious West Nile Virus infection are:

  • neck stiffness
  • disorientation
  • stupor
  • coma
  • tremors
  • convulsions
  • muscle weakness
  • paralysis

If symptoms observed are similar to those of a West Nile infection, a blood test will confirm if it is the virus, and treatment can begin.  There is no cure for West Nile Virus.  Severe cases are usually treated with hospitalization, intravenous fluids, respiratory management, and good nursing care.

To avoid infection with the West Nile Virus, the Center for Disease Control and Prevention recommends:

  • staying indoors at dawn, dusk, and in the early evening
  • wearing long pants and sleeves outdoors
  • spraying clothing with a repellant containing DEET or permethrin, and applying insect repellant with 35% DEET to exposed skin with 35% DEET. Always observe the manufacturer's Directions for Use, and note that some people may be sensitive to preparations containing DEET.


Although the chances of these summertime hazards affecting any one employee are rare, the effects can be devastating if they do.  As summer approaches, local governments can reduce the risk to their employees by taking some simple actions:

  • Send this information to all operations that employ outdoor workers, with a request from the mayor, county executive, town manager or other executive that each operation implement the appropriate precautions.
  • Require all supervisors of outdoor workers to incorporate the recommended precautions into their activities.
  • Direct all operations using outside workers to train those workers about these hazards, how to recognize and avoid potential problems and how to provide first aid if injuries or illness do occur.  Prepare simple handouts for workers that they can keep with them when they are away from the premises.
  • Tell employees that underlying medical conditions or medications they take may exacerbate the possibility of heat related illness.
  • Ensure that employees working outdoors in the summer have adequate access to plenty of fresh water.
  • Ensure that all employees working in the field can immediately contact emergency medical care if needed.

Following these recommendations will help reduce the number of work related injuries from summer hazards.  Training about these hazards is also a service to employees.  Summer hazards can also strike those who spend time outdoors for recreation.  Employees who are well trained about summer hazards on the job will be safer in their outdoor leisure activities as well.

Links to Other Resources

General Information
Home page for the Centers for Disease Control and Prevention
Home page for the Occupational Safety and Health Administration.

National Aeronautics and Space Administration article about electrical shocks, including those from lightning.
National Lightning Safety Institute article about lightning safety at outdoor events.
National Oceanic and Atmospheric Administration article about lightning safety.

Heat Stress
Provides entry to several OSHA sites with information on heat related illness in the workplace.
A detailed technical manual on heat stress in the workplace.
CDC Questions and answers about heat related illness.
An informational card on heat stress suitable for distribution to workers.  A Spanish version is also available.
National Institute for Occupational Safety and Health pamphlet Working in Hot Environments

Lyme Disease
Article about ticks and Lyme disease.
OSHA Hazard Information Bulletin on Lyme disease.

West Nile Virus
CDC Frequently Asked Questions about West Nile Virus.

Floor Marking
Floor marking comprehensive research, education and training; Mark floors to keep valuable lives separate from deadly hazards



5  Preventing Heat Stress in Agriculture, Zhao, Wei and Kerstig, Ann L., Rutgers Cooperative Extension,

6 Preventing Heat Stress in Agriculture, Zhao, Wei and Kerstig, Ann L.

7 Protect Yourself from Ticks and Lyme Disease, Smith-Fiola, Deborah, Rutgers Cooperative Extension,

8  Protect Yourself from Ticks and Lyme Disease, Smith-Fiola, Deborah, above.