Chlorine Toxicity Treatment & Management

Updated: Apr 11, 2022
  • Author: Gerald F O'Malley, DO; Chief Editor: Zygmunt F Dembek, PhD, MS, MPH, LHD  more...
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Approach Considerations

The most important aspect of treating patients exposed to chlorine gas is the provision of good supportive care. No antidotes are available. Emergency department (ED) personnel are at low risk for cross-contamination in cases of exposure to chlorine gas. However, the patient’s clothing should be removed if it has been contaminated with liquid chlorine. Wear appropriate protective gear during decontamination, especially if the exact toxin is not identified.

Evaluate the airway, breathing, and circulation. Provide supplemental oxygen (humidified if possible) as necessary; depending on the patient’s oxygen requirements, it may be delivered by nasal cannula, face mask, nonrebreather mask, noninvasive positive pressure ventilation, or intubation. Severe respiratory distress indicates the need for endotracheal intubation. Because of the risk of laryngospasm, several back-up modalities should be available at the time of intubation (ie, fiberoptic laryngoscope, cricothyrotomy tray).

Positive pressure ventilation with positive end-expiratory pressure (PEEP) set at 5-10 mm Hg may improve oxygenation in patients with noncardiogenic pulmonary edema and allow for lower fraction of inspired oxygen (FIO2) settings. An FIO2 greater than 50% for longer than 24 hours may result in oxygen toxicity.

Closely monitor the patient's fluid input and output because of the potential of pulmonary edema. Fluid restriction may be required and diuretics may be used to treat impending pulmonary edema.

Treat initial bronchospasm with beta agonists such as albuterol. Ipratropium may be added. Poor responses may require terbutaline or aminophylline. Nebulized lidocaine (4% topical solution) may provide analgesia and reduce coughing.

Other medications that may be used in the treatment of chlorine gas exposure include nebulized sodium bicarbonate and inhaled or systemic corticosteroids; however, evidence of efficacy is mixed. No evidence supports the use of prophylactic antibiotics.

Patients with skin or eye exposure to chlorine require copious irrigation with saline. Consider ophthalmologic consultation for patients with significant ocular involvement.

Consider admission and observation for the following patients, even if they are initially asymptomatic, as they are at increased risk of progression to respiratory failure:

  • Patients exposed to large concentrations in an enclosed environment
  • Patients with underlying respiratory or cardiovascular disease
  • Children

Cases of chronic reactive airway disease after acute exposures to chlorine gas are described in the literature. Consider referring patients for pulmonary function testing.


Prehospital Care

Prehospital care providers should take necessary precautions to prevent contamination. The use of a chemical cartridge respirator or self-contained breathing apparatus with full face mask should protect against the effects of chlorine gas on the upper and lower airways. This corresponds to Occupational Safety and Health Administration (OSHA) level A or level B personal protective equipment (PPE), with positive pressure self-contained breathing apparatuses with full face plates as well as protective overgarments. [25, 34]

Chemical-protective clothing should be worn because chlorine gas can condense on the skin and cause irritation and burns. [7] Staging areas should be situated upwind of the chlorine gas site.

Care at the site consists of the following:

  • Remove the individual from the toxic environment
  • Bring the container (double-bagged and sealed) or material safety data sheets (MSDS), if applicable, so medical personnel can identify the toxic agent; a digital photo of the product label (if possible) is preferred over the product itself to limit healthcare facility contamination
  • Commence primary decontamination of the eye and skin, if necessary
  • Real-time measurement of chlorine gas, both quantitative and qualitative, is possible through the use of mobile equipment

Chlorine gas is denser than air and accumulates close to the ground. Therefore, during chlorine-related accidents, people should be instructed to seek higher altitudes to avoid excessive exposure.

For related information, see Medscape's Disaster Preparedness and Aftermath Resource Center.


Hospital Admission

Patients who are asymptomatic on presentation and remain asymptomatic 6 hours after exposure may be discharged with appropriate instructions and in the presence of reliable family members. They should be advised that pulmonary edema may present in a delayed fashion after chlorine gas exposure.

Patients who present with symptoms that continue for 6 hours after exposure should be admitted for an observation period of at least 24 hours. If they are asymptomatic at 24 hours, they may be discharged with appropriate follow-up care. [35]

Consider admission and observation for the following patients, even if they are initially asymptomatic:

  • Patients exposed to large concentrations in an enclosed environment
  • Patients with underlying respiratory or cardiovascular disease
  • Children

Request critical care or pulmonary consultation for most admissions. Toxicology or poison control center consultation is recommended.


Skin and Eye Exposure

Skin exposures require copious irrigation with saline. Duration of skin irrigation, although not well studied, should probably be from 3-5 minutes. [7] If skin exposure is significant, wash with a mild soap and water.

In cases of suspected ocular injury, determine initial pH using a reagent strip capable of measuring the ranges 0-14. Irrigate the eye with normal saline until the pH returns to 7.4. Remove contact lenses (if present) prior to irrigation. Topical anesthetics help limit pain and improve patient cooperation during initial evaluation and management. [36]

After irrigation, evaluate the cornea with fluorescein staining under a slit lamp. Treat corneal abrasions with antibiotic ointment. Measure ocular pressures. Obtain ophthalmologic consultation for patients with significant ocular involvement.


Sodium Bicarbonate

In the past, several authors advocated nebulized sodium bicarbonate for treatment of chlorine gas exposure. The mechanism of action is believed to be the neutralization of hydrochloric acid formed in the airways. Most recommendations are based on anecdotal experience, and little supporting clinical data are available. [37, 38, 39] Theoretically, an exothermic reaction may occur when bicarbonate mixes with hydrochloric acid. [1, 40, 22] Animal studies suggest that nebulized sodium bicarbonate may cause chemical pneumonitis.

In a randomized, controlled trial in 44 patients with reactive airways dysfunction syndrome (RADS) due to chlorine inhalation, forced expiratory volume in 1 second (FEV1) values at 120 and 240 minutes were significantly higher in patients treated with nebulized sodium bicarbonate (4 mL of 4.20% NaHCO3 solution) than in those who received saline. [41] Treatment of all patients included corticosteroids and nebulized, short-acting β2-agonists. No significant difference in quality of life questionnaire scores was found between the two groups.



Inhaled and parenteral steroids have been used with many patients exposed to chlorine gas, but no strong clinical evidence supports their use except in patients with an exacerbation of underlying reactive airway disease. [39] Some animal studies demonstrate better lung compliance and arterial oxygen tension when inhaled steroids are initiated within 30 minutes of exposure.

Parenteral steroids are advocated by some authors to prevent short-term reactions and long-term sequelae. [42, 43] Other authors argue against this practice, because of insufficient clinical trials. [1]


Investigational Treatments

Studies in animal models have found benefit from postexposure treatment with N-acetylcysteine (NAC) [44] and a combination of ascorbate and deferoxamine. [45] Treated rats demonstrated favorable histopathological changes in pulmonary tissue compared with controls.

The role of transient receptor potential (TRP) channel inhibitors in acute lung injury secondary to chlorine and other toxic inhalational agents is becoming more clear, and TRP inhibitors have been shown to suppress pulmonary inflammation in this setting. [46]  However, caution should be used in interpreting these studies because these interventions have not been studied in humans for this condition.




Proper labeling and avoiding mixing chemicals facilitate prevention. Household cleaning products should not be mixed. Using proper precautions when handling swimming pool chemicals reduces risks. Adequate ventilation is necessary when handling any potentially noxious chemical.

As accidental occupational exposures to chlorine gas comprise a significant percentage of severe exposures, proper methods of training and supervision are beneficial. Enforcement of existing work safety regulations may lead to fewer exposures. On a larger scale, chemical warfare treaties between countries and the safe transportation and handling of industrial chlorine compounds facilitate deterrence.

Training prehospital and hospital providers in the management of chemical casualties can improve the treatment provided to exposed personnel while minimizing personal risks. Hospitals can establish mass casualty plans and perform drills to ensure that preparations are adequate in the event of a large-scale industrial accident.

Long-term exposure to small amounts of chlorine gas may contribute to pulmonary disease. [47] The current US legal limit for occupational exposure to chlorine gas enforceable by the Occupational Safety and Health Administration (OSHA) is 0.5 ppm averaged over a 10-hour day or a 40-hour work week and a short-term exposure limit of 1 ppm. [48]