Venomous spiders found in the United States include the black widow and the brown recluse. These spiders can be dangerous to outdoor workers including farmers, foresters, landscapers, groundskeepers, gardeners, painters, roofers, pavers, construction workers, laborers, mechanics, and any other worker who spends time outside. These spiders occasionally find their way inside structures or buildings and can also present a risk to indoor workers including machine operators, janitors, and cashiers ( Bureau of Labor Statistics Monthly Review - Insects bites, stings cause thousands of workplace injuries ). Spiders are usually not aggressive and most bites occur because a spider is trapped or unintentionally contacted. It is important for employers to educate their workers about their risk of exposure to venomous spiders, how they can prevent and protect themselves from spider bites, and what they should do if they are bitten.
Black widow spiders are found throughout North America, but are most common in the southern and western areas of the United States. They are identified by the pattern of red coloration on the underside of their abdomen. They are usually found in workplaces containing undisturbed areas such as woodpiles, under eaves, fences, and other areas where debris has accumulated. They may also be found living in outdoor toilets where flies are plentiful.
Black widow spiders build webs between objects, and bites usually occur when humans come into direct contact with these webs. A bite from a black widow can be distinguished from other insect bites by the two puncture marks it makes in the skin. The venom is a neurotoxin that produces pain at the bite area and then spreads to the chest, abdomen, or the entire body.
The brown recluse spider, also known as the violin spider, is most commonly found in the Midwestern and southern states of the United States. It is brown in color with a characteristic dark violin-shaped (or fiddle-shaped) marking on its head and has six equal-sized eyes (most spiders have eight eyes). Brown recluse spiders are usually found in workplaces with secluded, dry, sheltered areas such as underneath structures logs, or in piles of rocks or leaves. If a brown recluse spider wanders indoors, they may be found in dark closets, shoes, or attics.
The brown recluse spider cannot bite humans without some form of counter pressure, for example, through unintentional contact that traps the spider against the skin. Bites may cause a stinging sensation with localized pain. A small white blister usually develops at the site of the bite. The venom of a brown recluse can cause a severe lesion by destroying skin tissue (skin necrosis). This skin lesion will require professional medical attention.
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 the following:
- 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
- Nausea and vomiting
- Anxiety or restlessness
- High blood pressure
Employers should protect their workers from spider bites by training them on:
- Their risk of exposure to spiders
- How to identify spiders
- How to prevent exposure to spiders
- What they should do if they are bitten by a spider
Workers can take the following preventive steps:
- Inspect or shake out any clothing, shoes, towels, or equipment before use.
- Wear protective clothing such as a long-sleeved shirt and long pants, hat, gloves, and boots when handling stacked or undisturbed piles of materials.
- Minimize the empty spaces between stacked materials.
- Remove and reduce debris and rubble from around the outdoor work areas.
- Trim or eliminate tall grasses from around outdoor work areas.
- Store apparel and outdoor equipment in tightly closed plastic bags.
- Keep your tetanus boosters up-to-date (every 10 years). Spider bites can become infected with tetanus spores.
Workers should take the following steps if they are bitten by a spider:
- Stay calm. Identify the type of spider if it is possible to do so safely. Identification will aid in medical treatment.
- Wash the bite area with soap and water.
- Apply a cloth dampened with cold water or filled with ice to the bite area to reduce swelling.
- Elevate bite area if possible.
- Do not attempt to remove venom.
- Notify your supervisor.
- Immediately seek professional medical attention.
OSHA Spider Fact Sheets
One-page fact sheets (PDF) with information on spider identification, habitat, and bite symptoms as well as bite treatment and worker protection. From the Occupational Safety and Health Administration.
Spider Bite Medical Information
MedlinePlus web pages with descriptions of bite symptoms and hospital treatment information. From the National Library of Medicine.
General tips to prevent and treat spider bites. From the Ohio State University Extension, Agriculture Safety Program.
Summary information about the spider, its bites, first aid, and pest management. From Ohio State University.
Identification of brown recluses and text descriptions of spiders commonly confused with brown recluses. The page describes the spider’s range and characteristics. It includes a section on medical misdiagnoses (that is, injuries misattributed to spider bites) and a section on pest control. From the University of California Integrated Pest Management Program.
- Page last reviewed: July 30, 2015
- Page last updated: July 30, 2015
- Content source:
- National Institute for Occupational Safety and Health Education and Information Division