Chlorine Gas Exposure

First aid: what to do right now

1. Get out to fresh air immediately. Go upwind and uphill, because chlorine is heavier than air and collects in low areas.
2. Call for help: call 911 or your local emergency number for any breathing difficulty. For mild symptoms, call Poison Help at 1-800-222-1222 (US) for advice.
3. Remove contaminated clothing and seal it in a plastic bag. Cut off clothing that would have to be pulled over the head.
4. Rinse skin with plenty of water for at least 15 minutes.
5. Rinse the eyes with clean, lukewarm water for 10 to 15 minutes. Remove contact lenses if they come out easily.
6. Stay upright and rest. Exertion increases the dose and the strain on the lungs.
7. Do not re-enter the area to rescue others unless you have proper protection.

How chlorine harms the body

Chlorine is a yellow-green gas with a sharp bleach smell that most people notice at very low levels. Once inhaled, it dissolves in the moisture of the airways and forms hydrochloric acid and hypochlorous acid, and releases reactive oxygen. These damage the cells lining the airways and the air sacs.

Because chlorine is moderately water-soluble, it irritates both the upper airways (eyes, nose, throat) and the deeper lungs. Higher doses reach the air sacs, making them leak fluid into the lungs. This is pulmonary edema and can lead to acute respiratory distress syndrome.

How bad the injury is depends on concentration, duration, how enclosed the space is, how hard you were breathing, and whether you already have lung disease.

Sources of exposure

• Home: mixing bleach with acidic cleaners, vinegar or ammonia, especially in a small bathroom
• Pools: adding pool chemicals incorrectly, chlorinator malfunctions, or poorly ventilated indoor pools
• Work: water treatment, paper and plastics manufacturing, cleaning industries
• Accidents: railway or truck tanker spills, which can expose whole communities
• Chemical attacks: chlorine has been used as a weapon

Symptoms

Immediate symptoms

• Burning, watering, red eyes and blurred vision
• Burning of the nose, throat and mouth
• Coughing, choking and a feeling of chest tightness
• Wheezing and shortness of breath
• Nausea, vomiting and headache
• Skin redness or burns where liquid chlorine or very high gas levels touched

Delayed symptoms

After heavy exposure, symptoms can worsen over 2 to 24 hours as fluid builds up in the lungs: worsening breathlessness, rapid breathing, crackles in the chest and frothy sputum. This is why anyone with more than minor symptoms should be observed in a hospital.

Diagnosis

Diagnosis is based on the history of exposure and symptoms. In the ER, doctors check:

• oxygen levels with a pulse oximeter, and blood gases if breathing is labored
• a chest X-ray, which may be normal at first and show edema later
• lung function (peak flow or spirometry) if you are wheezing
• the eyes, with a dye test for corneal burns if they remain painful

Treatment

There is no specific antidote for chlorine. Treatment supports the lungs while they heal:

• Humidified oxygen for low oxygen levels
• Inhaled bronchodilators such as albuterol for wheezing
• Nebulized sodium bicarbonate is used in some centers to neutralize acid in the airways, although the evidence is limited
• Corticosteroids may be given for severe wheezing or in people with asthma
• Breathing support with CPAP or a ventilator for severe pulmonary edema or ARDS
• Eye care with irrigation and lubricating or antibiotic drops for corneal injury
• Observation for at least 6 hours, and often overnight, after significant exposure

People who only had brief upper-airway irritation and recover fully in fresh air are usually sent home with advice on symptoms to watch.

Complications and outlook

Most people with mild to moderate exposure recover fully within a few days. After heavy exposure, possible long-term effects include:

• reactive airways dysfunction syndrome, an asthma-like condition with cough and wheeze that starts within 24 hours of a single high exposure and can last months to years
• worsening of existing asthma or COPD
• bronchiolitis obliterans (scarring of the small airways), which is rare
• chronic cough and reduced lung function

Anyone with ongoing breathlessness, cough or wheeze after exposure should have follow-up lung function testing.

Prevention

• Never mix cleaning products. Use one at a time and rinse surfaces between them.
• Clean in well-ventilated rooms with windows open and a fan running.
• Store pool chemicals dry, separately and according to the label, and add chemicals to water, never water to chemicals.
• Follow workplace safety rules and use respirators where required.
• During a community chlorine release, follow emergency instructions to evacuate or to shelter indoors on a higher floor with windows and vents closed.

Frequently asked questions

How long do chlorine gas symptoms last?

Mild eye and throat irritation usually clears within a few hours of fresh air. Coughing and chest tightness after moderate exposure can last a few days. After heavy exposure, lung injury may take weeks to recover, and some people develop long-lasting asthma-like symptoms.

What happens if you mix bleach and ammonia?

Bleach and ammonia react to release chloramine gases, which irritate the eyes, throat and lungs much like chlorine. Mixing bleach with acids such as vinegar or toilet bowl cleaners releases chlorine gas itself. Leave the room, open windows if it is safe, and call Poison Help for advice.

Can chlorine gas exposure be delayed?

Yes. After a heavy exposure, fluid can build up in the lungs over 2 to 24 hours, even if you felt only moderately unwell at first. Anyone with more than mild, quickly resolving symptoms should be checked in an ER and watched for several hours.

Is smelling pool chlorine dangerous?

The usual chlorine smell at a pool is mostly from chloramines and is not dangerous for most people, although it can irritate eyes and trigger asthma. Exposure becomes dangerous when chemicals are mixed incorrectly or a chlorinator fails, releasing a strong cloud of gas.

What should I do after inhaling bleach fumes?

Move to fresh air right away and rinse your eyes and skin if they sting. Mild throat and eye irritation should settle within an hour. If you have breathing difficulty, wheezing, chest pain or a persistent cough, get emergency care.