Stinging Insects

Every crew has the man who gets stung and shrugs. He has been stung on this site, on the last one, and on his own roof, and nothing has ever happened. That reputation is what gets used to make the decision when somebody else gets stung — if he was fine, this will be fine. It is the wrong lesson drawn from the right observation. This Stinging Insects Toolbox Talk (Safety Talk / Tailgate Talk) is about why.

Here is the distinction that carries this whole talk: an allergic reaction to a sting requires that you have been stung before — so a history of being stung without trouble is not evidence of safety, it is the precondition. The Merck Manual puts it plainly: hymenoptera venoms cause local toxic reactions in all people, and allergic reactions only in those previously sensitised. The first sting does not usually hurt you. It teaches your immune system the venom. The reaction that kills is somebody's first allergic reaction, not their first sting — which is exactly why it arrives with no warning and lands on a man everybody thought was fine.

Where the boundary of this talk sits#

The first aid response system — the three-to-four minute window, trained-person availability, AEDs — belongs to the first aid and AED talk. What is in the kit and how the crew is familiarised with it belongs to the first aid kit talk. Skin reactions to plants and chemicals belong to the skin hazards talk, and urushiol specifically to the poison ivy talk. This talk owns the sting itself: what the venom does, who is at risk, and what the crew does in the first thirty minutes.

The numbers#

Small percentages, but a crew is a lot of people over a lot of summers.

Systemic allergic reactions to insect stings occur in roughly 3% of adults and about 1% of children. In adults those reactions more commonly involve airway obstruction or low blood pressure; in children they are more often limited to the skin.

At least 50 fatal reactions to insect stings are reported each year in the United States, and published guidance notes that many sting fatalities are probably not recognised as such — sudden deaths during sting season have been found on postmortem to carry the markers of anaphylaxis.

And the timing is the operational number: up to 96% of fatal reactions begin within 30 minutes of the sting. Severe reactions can progress to shock, cardiac arrest and unconsciousness in ten minutes or less. Laryngeal swelling and circulatory failure are the most common causes of death.

Who is actually at risk#

Nobody on the crew can be cleared by history alone, but some histories raise the number sharply.

A previous large local reaction — a limb that swelled up over a day or two — carries a 5 to 10% risk of a systemic reaction to a future sting.

A previous systemic reaction carries a variable risk on the next sting: as low as 10 to 15% for the mildest reactions and in some children, but as high as 70% in adults who have had the most severe recent reactions.

Read those together. A man who once had a bad swollen arm is not in the same category as a man who has never reacted, and a man who has had a systemic reaction is in a different category again. That information is only useful if somebody has asked for it before the sting happens.

The other route: too much venom, no allergy#

There is a second, entirely separate way a sting event kills, and it does not involve allergy at all.

Venom is toxic to everybody in sufficient dose. The Merck Manual gives the tolerance as about 22 stings per kilogram of body weight in an unsensitised person — so an average adult can survive more than 1,000 stings, while 500 stings can kill a child.

Those numbers sound absurd until you remember how sites generate them. Yellowjackets nest in the ground, in dirt mounds, in old logs and in wall voids. A strimmer, a mower, an excavator bucket, a compactor or a boot through a rotten stump does not produce one sting. It produces a defending colony. Mass stinging is a construction hazard specifically because of the machinery.

What to do, in order#

Get the person away from the nest first. Vespids can sting repeatedly and will pursue. Move indoors or into a vehicle; do not stand and swat.

Remove a honeybee sting immediately. A honeybee leaves the sting and venom sac behind, and it continues to inject. Speed matters far more than technique — scrape it, flick it, pull it, but get it out now rather than looking for a credit card. Wasps, hornets and yellowjackets do not leave a sting.

Then watch the person, not the sting. Local pain, redness and swelling are normal. What you are looking for is anything away from the sting site: hives elsewhere on the body, swelling of the lips, tongue or throat, difficulty breathing, wheeze, tight chest, dizziness, faintness, nausea, vomiting, or a sense of impending doom.

If any of that appears, this is anaphylaxis. Epinephrine is the treatment of choice, and it is the only thing that treats it. An antihistamine may reduce itching but it does not treat anaphylaxis — reaching for one instead of calling for help has killed people. Call emergency services, use the person's auto-injector if they have one and you are trained and permitted to, keep them lying down, and do not let them stand up or walk to the vehicle.

Do not send them back to work and do not let them drive. Even where symptoms settle, reactions can return.

What the crew needs before the season, not during it#

Ask who carries an auto-injector. This is the single highest-value thing in this talk and it costs one question at induction. Somebody who has had a systemic reaction usually knows it and usually carries a device — but nobody knows where it is, and it is often in a van at the other end of the site.

Then agree where it lives and who can fetch it. A device locked in the wrong vehicle is not a control.

Check whether your kit can carry one. OSHA's own guidance notes that several states have passed laws allowing entities, rather than only individuals, to hold auto-injectable epinephrine in their first aid kits — so the answer depends on where you are working. Kit contents and classes are covered in the first aid kit talk.

And know how the emergency services reach you. On a large or remote site the useful number is not the sting, it is the minutes between the sting and a paramedic.

Reducing the encounters#

Survey before you disturb. Walk the area for nests before strimming, mowing, clearing, or breaking ground — particularly around stumps, logs, dirt mounds, voids, eaves and site cabins.

Mark and report nests rather than dealing with them yourself, and get them treated outside working hours by somebody competent.

Cover up. Long sleeves, long trousers, socks and boots. Light plain colours; avoid floral prints and strong scents.

Watch the food. Open drink cans and bins draw yellowjackets, and a can that has been standing is how stings end up inside the mouth and throat, which is an airway problem regardless of allergy.

Move away calmly from a single insect, and do not swat at it near a nest.

Where the duty sits#

There is no OSHA standard for stinging insects. State that plainly.

What applies is general. 1926.50 covers medical services and first aid — the availability of a person trained in first aid where no infirmary, clinic or hospital is reasonably accessible, adequate supplies, and communication for emergency transport. 1926.21(b)(2) requires the employer to instruct each employee in the recognition and avoidance of unsafe conditions, which is precisely what this talk is. 1926.28(a) and 1926.95 cover personal protective equipment. And Section 5(a)(1) of the OSH Act, the General Duty Clause, requires a workplace free of recognised hazards likely to cause death or serious physical harm.

Note that prescribing, supplying and administering epinephrine is a medical and legal question that varies by state, and it needs to be settled with your medical provider before somebody is on the ground — not on the day.

What can go wrong?#

Treating "he's been stung loads of times" as clearance, when it is the precondition for sensitisation.

Never asking who carries an auto-injector, so nobody knows on the day.

Watching the sting instead of the person, and missing hives, wheeze or throat swelling elsewhere.

Reaching for an antihistamine during anaphylaxis instead of epinephrine and an ambulance.

Letting somebody drive themselves to hospital, or walk to the gate.

Strimming, mowing or breaking ground without surveying for ground nests first.

Dealing with a nest yourself during working hours, with the crew nearby.

Sending somebody back to work after symptoms settle, when reactions can return.

How do we manage this properly?#

Ask at induction who has ever had a reaction to a sting and who carries an auto-injector, and record it.

Agree where the device is kept and who can get to it, and make sure that is not a locked van at the far end of the site.

Settle the epinephrine question with your medical provider in advance — what your kit may hold and who may use it, which varies by state.

Survey for nests before any ground disturbance or vegetation work, and mark what you find.

Have nests treated by somebody competent, outside working hours.

Cover up and keep food and drink contained, especially in late summer when colonies are largest and most aggressive.

Move a stung worker away from the nest first, then remove a honeybee sting immediately by any method.

Watch for thirty minutes, because up to 96% of fatal reactions begin inside that window.

On any symptom away from the sting site, treat it as anaphylaxis: call emergency services, epinephrine, keep them lying down, and do not let them stand.

Before you start#

• Confirm who on this crew has ever had a reaction to a sting.
• Confirm who carries an auto-injector and where it is right now.
• Confirm the crew knows the route and how emergency services reach this location.
• Confirm the area has been surveyed for ground nests before strimming or breaking ground.
• Confirm any known nest is marked and scheduled for treatment out of hours.
• Confirm sleeves, trousers and boots are being worn for vegetation work.
• Confirm food and drink are contained and bins are covered.
• Confirm everyone knows an antihistamine is not treatment for anaphylaxis.

Talk it over#

• Has anyone here ever had more than local swelling from a sting?
• Does anyone carry an auto-injector, and where is it at this moment?
• Where on this site would a ground nest be, and who is about to disturb it?
• If somebody was stung at the far end of the site right now, how long until help reached them?

The bottom line#

An allergic reaction to a sting requires that you have been stung before, so a history of being stung without trouble is not evidence of safety — it is the precondition. The Merck Manual states that hymenoptera venoms cause local toxic reactions in all people and allergic reactions only in those previously sensitised: the first sting teaches the immune system, and the reaction that kills is somebody's first allergic reaction rather than their first sting. Systemic allergic reactions occur in about 3% of adults and 1% of children, with adults more likely to have airway obstruction or hypotension; at least 50 fatal reactions are reported each year in the US, and many sting fatalities are probably unrecognised. The operational number is timing: up to 96% of fatal reactions begin within 30 minutes, severe reactions can reach shock and cardiac arrest in ten minutes or less, and laryngeal swelling and circulatory failure are the most common causes of death. History raises the odds: a previous large local reaction carries a 5–10% risk of a systemic reaction next time, and a previous systemic reaction carries 10–15% at the mildest up to 70% in adults with the most severe recent reactions. There is also a second, non-allergic route — venom is toxic in dose, with tolerance around 22 stings per kilogram, so an adult may survive over 1,000 stings while 500 can kill a child — and construction generates exactly that scenario because yellowjackets nest in the ground, dirt mounds, old logs and wall voids, and a strimmer, mower, bucket or boot releases a colony. On the day: move away from the nest, remove a honeybee sting immediately — speed matters more than technique (wasps and hornets leave none), then watch the person, not the sting, for anything away from the site — hives, lip, tongue or throat swelling, wheeze, dizziness, faintness. That is anaphylaxis, and epinephrine is the treatment of choice; an antihistamine may reduce itching but does not treat it. Call emergency services, keep them lying down, never let them drive. Before the season: ask who carries an auto-injector and where it is, and settle with your medical provider what your kit may hold — OSHA guidance notes several states allow entities, not only individuals, to hold auto-injectable epinephrine. There is no OSHA standard for stinging insects: duties run through 1926.50 medical services and first aid, 1926.21(b)(2) instruction, 1926.28(a) and 1926.95 for PPE, and Section 5(a)(1).

Frequently asked questions about stinging insects#

Someone has been stung many times with no problem — does that mean they are safe?

No, and this is the most dangerous belief on site. The Merck Manual states that hymenoptera venoms cause local reactions in everyone but allergic reactions only in those previously sensitised — meaning a person must have been stung before to develop the allergy at all. Earlier stings without trouble are how sensitisation happens, not proof it did not. The fatal event is usually somebody's first allergic reaction, which is why it arrives without warning.

How quickly does a serious reaction start?

Fast. Up to 96% of fatal reactions begin within 30 minutes of the sting, and a severe reaction can progress to shock, cardiac arrest and unconsciousness in ten minutes or less. That is why the crew watches a stung worker for half an hour rather than sending them back to the face, and why the distance to emergency help matters more than anything in the first aid kit.

What are we actually watching for?

Anything away from the sting site. Pain, redness and swelling at the sting itself are normal. The warning signs are hives elsewhere on the body, swelling of the lips, tongue or throat, difficulty breathing, wheeze, chest tightness, dizziness, faintness, nausea or vomiting. Laryngeal swelling and circulatory failure are the most common causes of death, so anything involving the airway or a person going pale and weak is an emergency.

Will an antihistamine deal with it?

No. Epinephrine is the treatment of choice for anaphylaxis and is the only thing that treats it. An antihistamine may reduce itching but does not treat anaphylaxis, and reaching for one instead of calling for help has cost lives. Call emergency services, use the person's auto-injector if they have one and you are trained and permitted, keep them lying down, and do not let them stand up or walk.

Does it matter how you remove a bee sting?

Only that you do it immediately. A honeybee leaves the sting and venom sac behind and it keeps injecting, so speed matters far more than technique — scrape, flick or pull it, but do not spend time looking for a card to scrape with. Wasps, hornets and yellowjackets do not leave a sting behind and can sting repeatedly, which is why the first move with those is to get the person away from the nest.

Can a sting event kill somebody who is not allergic?

Yes, by dose. Venom is toxic to everyone in sufficient quantity, and the Merck Manual gives tolerance in an unsensitised person as roughly 22 stings per kilogram of body weight — so an average adult can withstand more than 1,000 stings while 500 stings can kill a child. Construction produces those numbers because yellowjackets nest in the ground, in dirt mounds, old logs and wall voids, and a strimmer, mower or excavator bucket releases the whole colony at once.

What should be arranged before the season starts?

Three things, and all are free. Ask who has ever reacted to a sting and who carries an auto-injector, then agree where that device is kept and who can reach it — not a locked van at the far end of the site. Third, settle with your medical provider what your first aid kit may hold and who may use it; OSHA guidance notes that several states have passed laws allowing entities, rather than only individuals, to hold auto-injectable epinephrine.

Download the stinging insects toolbox talk PDF#

Get this stinging insects toolbox talk as a print-ready PDF — available in English, Spanish, Portuguese, and Turkish. Print it, hand it to the crew, and collect signatures on the included attendance sheet.

Download the PDF — free account required. New members get 5 free downloads.

Related toolbox talks#

• First Aid & AED
• First Aid Kit Familiarization
• Poison Ivy, Oak & Sumac
• Emergency Response

Sources#

• OSHA, Insect Stings (OSHA 4137): https://www.osha.gov/sites/default/files/publications/OSHA4137.pdf
• Merck Manual Professional Edition, Insect Stings: https://www.merckmanuals.com/professional/injuries-poisoning/bites-and-stings/insect-stings
• American Family Physician, Stinging Insect Allergy: https://www.aafp.org/afp/2003/0615/p2541

This talk is general awareness guidance for training purposes. It is not medical advice and nothing in it is a diagnosis or a prescription. Whether epinephrine may be held on site and who may administer it varies by jurisdiction and must be settled with a qualified medical provider in advance. Anyone with symptoms away from the sting site should be treated as a medical emergency and assessed by a qualified medical professional.

Written by FieldSafetyTalk's safety professional — a CSP, ASP, CHST and OSHA Authorized Outreach Trainer with 14+ years of international construction safety experience across federal, heavy civil, and industrial projects.

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