Biological Hazards of Outdoor Summer Work

It’s important to know safety tips regarding some plants, spiders, and ticks.

By Alexandra Walsh

In addition to physical hazards associated with working outdoors in the summer heat, outdoor workers can face biological hazards as well.

Whether poisonous plants, spiders, or ticks, employers should protect their workers from the biological hazard by training them in:

  • Their risk of exposure to the hazard
  • How to identify the hazard
  • How to prevent exposure to the hazard
  • What they should do if they are exposed to the hazard.

Poisonous Plants

Many native and exotic plants are poisonous to humans when ingested or if there is skin contact with chemicals on the plant. The most common problems with poisonous plants arise from contact with the sap oil of several native plants that cause an allergic skin reaction.

Poison ivy, poison oak, and poison sumac release an oil called urushiol when the leaf or other parts of the plant are bruised, damaged, or burned. When exposed to as little as 50 micrograms of urushiol, an amount less than one grain of table salt, 80% to 90% of adults will develop a rash.

Depending on where it occurs and how broadly it is spread, the rash may prevent or completely stop a person from working.

Workers may become exposed to urushiol through:

  • Direct contact with the plant
  • Touching tools, livestock, or clothing that have urushiol on them
  • Inhaling particles containing urushiol from burning plants.
    Workers can prevent contact with poisonous plants by:
  • Wearing long sleeves, long pants, boots, and gloves
  • Washing exposed clothing separately in hot water with detergent
  • Using barrier skin creams and lotions that may offer some protection before contact. Barrier creams should be washed off and reapplied twice a day.
  • Cleaning tools after use with rubbing alcohol (isopropanol or isopropyl alcohol) or soap and lots of water. Urushiol can remain active on the surface of objects for up to five years. Use disposable gloves during this process.
  • Not burning plants that could be poison ivy, poison oak, or poison sumac. Inhaling smoke from burning plants can cause severe allergic respiratory problems.

Workers who have come in contact with poisonous plants should:

  • Rinse skin immediately with rubbing alcohol, specialized poison plant washes, degreasing soap (such as dishwashing soap) or detergent and lots of water. Rinse frequently so wash solutions don’t dry on the skin and further spread the urushiol.
  • Scrub under fingernails with a brush.
  • Apply wet compresses, calamine lotion, or hydrocortisone cream to the skin to reduce itching and blistering. Do not apply to broken skin or open blisters.
  • Take an antihistamine (such as Benadryl) to help relieve itching. Follow directions on the package. Drowsiness may occur.
  • Call 911 or go to a hospital emergency room if the worker is suffering severe allergic reaction, such as swelling or difficulty breathing, or had a severe reaction in the past.
Safety Products by NGWA Available Online
The National Ground Water Association has a product titled Safety Meetings for the Groundwater Industry consisting of 52 sheets that have talking points on a variety of industry-related topics and a place for signatures for those in attendance. Among the subjects are electrical safety on a drilling rig, lock out-tag out, shock from electrical tools, treating someone in shock, and more. It and other safety products can be found in the online store here.

Venomous Spiders

Spiders producing venom include the black widow and the brown recluse. These spiders can not only be dangerous to outdoor workers but those inside buildings as well. These spiders occasionally find their way inside structures and present risks to indoor workers.

Spiders are usually not aggressive and most bites occur because a spider is trapped or unintentionally contacted.

Workers can take the following preventive steps:

  • Inspect or shake out any clothing, shoes, towels, or equipment before using.
  • Wear long-sleeved shirt and long pants, hat, gloves, and boots when handling stacked or undisturbed piles of materials.
  • Reduce empty spaces between stacked materials.
  • Remove and reduce debris and rubble around outdoor work areas.
  • Trim or eliminate tall grasses around outdoor work areas.
  • Store apparel and outdoor equipment in tightly closed plastic bags or containers.
  • Keep tetanus boosters up-to-date (every 10 years).

Spider bites can become infected with tetanus spores.

Symptoms associated with spider bites can vary from minor to severe. Although extremely rare, death can occur in the most severe cases.

Possible symptoms resulting from a spider bite include:

  • Itching or rash
  • Pain radiating from the site of the bite
  • Muscle pain or cramping
  • Reddish to purplish color or blister
  • Increased sweating
  • Difficulty breathing
  • Headache, fever, chills
  • Nausea and vomiting
  • Anxiety or restlessness
  • High blood pressure.
    If bitten by a spider, workers should:
  • Stay calm. Identify the type of spider if possible to do so safely. Identification will aid in medical treatment.
  • Wash the bite area with soap and water.
  • Apply cloth dampened with cold water or filled with ice to the bite area to reduce swelling.
  • Elevate the bite area if possible.
  • Do not attempt to remove venom.
  • Notify your supervisor.
  • Seek professional medical attention immediately.

Tick Bites

Ticks can be infected with bacteria, viruses, or parasites. Tick-borne pathogens can be passed to humans by the bite of infected ticks.

Some of the most common tick-borne diseases in the United States include Colorado tick fever, Lyme disease, Powassan encephalitis, Rocky Mountain spotted fever, Southern tick-associated rash illness, and Tick-borne relapsing fever.

Lyme disease is the most commonly reported tick-borne disease. Each year, approximately 30,000 cases of Lyme disease are reported to the Centers for Disease Control and Prevention (CDC) by state health departments and the District of Columbia. The number of reported cases of Lyme disease in the United States has tripled since the late 1990s.

Outdoor workers are at risk of exposure to ticks and diseases if their worksites are anywhere near woods, bushes, high grass, or leaf litter. Outdoor workers in most regions should be extra careful and protect themselves in the spring, summer, and fall when ticks are most active. Ticks can be active all year in some regions with warmer weather.

Employers should protect their workers from tick-borne diseases by taking these steps:

  • Recommend workers wear light-colored, long-sleeved shirts, long pants, socks, and hat when possible; if worker uniforms are provided, long-sleeved shirts and long pants.
  • Provide workers with repellents (containing 20% to 30% DEET) to use on their skin and clothing for protection against tick bites.
  • Provide workers with repellents (such as Permethrin) to provide greater protection. Permethrin kills ticks on contact. It can be used on clothing but not skin.
  • When avoiding woody or leafy areas is not possible, personal protective measures are particularly important.

If work in higher-risk sites must occur, remove leaf litter and mow or cut back tall grass and brush.

To protect themselves from tick bites, workers should:

  • Follow repellent label directions for use.
  • Reapply repellents as needed.
  • Use Permethrin on clothing but should not be used on skin.
    -One application of Permethrin to pants, socks, and shoes typically stays effective through several washings.
    -Pre-treated clothing is available and remains protective for many washings (up to 70).
  • Check skin and clothes for ticks every day. Immature forms of ticks are very small and may be hard to see.
    -Shower or bathe as soon as possible after working outdoors to wash off and check for ticks.
    -Remember to check your hair, underarms, and groin for ticks.
    -Immediately remove ticks from you body using fine-tipped tweezers.
    -Grasp the tick firmly and as close to your skin as possible.
    -Pull the tick’s body away from your skin with a steady motion.
    -Clean the area with soap and water.
    -Removing infected ticks within 24 hours reduces your risk of being infected with the Lyme disease bacterium.
  • Wash and dry work clothes in a hot dryer to kill any ticks present.
  • Learn the symptoms of tick-borne diseases.
  • If you develop symptoms of a tick-borne disease, seek medical attention promptly. Be sure to tell your health care provider you work outdoors in an area where ticks may be present.


Working outdoors can be a tremendous perk for many professionals in the groundwater industry. But at the same time, remembering to be safe from some of the biological hazards around you is a must.

OSHA Quick Card
An OSHA Quick Card on biological outdoor hazards can be found here.

Alexandra Walsh is the vice president of Association Vision, a Washington, D.C.–area communications company. She has extensive experience in management positions with a range of organizations.