Some 44 million tons are produced worldwide, much transported by road and rail. In the last decades most acute exposures have been from industrial spills, chemical mixing errors and industrial accidents, and these have led to injuries and deaths. Chronic exposure to lower levels has occurred in workplace and public spaces such as swimming pools. Domestic exposure has often resulted from the mixing of chlorine bleach with acidic washing agents such as acetic, nitric and phosphoric acid [ 5 , 6 , 7 ].
Chlorine was first used as a weapon during World War I [ 8 ]. It was initially lethal to large numbers of troops at Ypres in Respiratory protection was swiftly developed but did not protect most civilians. At one point it was so prevalent on the Western front that respirators were developed for horses and carrier pigeons.
Its use in war was subsequently banned by consensus at the United Nations UN [ 9 ]. The widespread use of chlorine in industry means that production and storage cannot be banned, even in regimes where chemical weapons have been surrendered.
Therefore, it is available to those seeking to weaponise it. Its re-emergence in recent decades has been widely reported in conflict zones, including Sri Lanka, Iraq and Syria, and many incidents have been verified by the UN. Chlorine gas has been used recently in besieged urban areas, where it seeps down into cellars and drives the population out into the open.
Its widespread storage and transportation also make it susceptible to terrorist attack, leading to spills, as has occurred several times in Iraq. Doctors in and beyond conflict zones therefore need to be aware of the management of chlorine gas exposure. Humans can detect very low levels of chlorine gas. The threshold concentration for detection of the odour is around 0. Immediate symptoms relate to concentration:. Chlorine gas is classed as a pulmonary agent or choking agent others include phosgene, diphosgene and chloropicrin.
Once inhaled, it diffuses into the respiratory epithelium, where most damage is initiated by its dissolution into hydrochloric and hypochlorous acids. Further damage occurs with activation of inflammatory cells and subsequent release of oxidants and proteolytic enzymes. Hydrochloric and hypochlorous acids also target the epithelia of the ocular conjunctivae, leading to acid injury to the eye [ 11 ]. The intermediate water-solubility of chlorine means it is mostly absorbed in the conducting compartment of the respiratory tract, from the nose to the level of the bronchi, and higher exposure is needed to cause alveolar damage.
High concentrations of chlorine ppm or more cause mixed airway and alveolar damage. Where alveolar damage occurs its contribution to the clinical picture is usually less pronounced than that of upper airway damage, with a high prevalence of signs of obstructive impairment.
The upper airways and eyes are irritated at low levels of exposure. At higher levels, the nasopharynx and larynx are injured. At very high levels, alveolar damage occurs rapidly. Pulmonary oedema is the most significant life-threatening effect.
The level of harm is influenced by victim factors age, current lung health, presence of bronchospasm response, exertional state and metabolic rate, history of smoking and environmental factors intensity and duration of exposure, quality of ventilation in the space in which exposure occurs. Greater exposure is associated with greater potential harm [ 11 ].
This depends on the level of exposure. During or immediately after exposure to dangerous concentrations of chlorine, the following signs and symptoms are typical:. These symptoms are not specific for chlorine; many are also features of exposure to other chemical agents such as phosgene and tear gas, and to some neurological agents.
For those exposed, the most obvious clues to chlorine as the causative agent are the characteristic smell of chlorine and the sight of the yellow-green, dense gas at ground level. The presence and speed of development of pulmonary oedema depend on exposure intensity. Patients present with worsening respiratory distress. If pulmonary oedema is to develop, it usually does so within hours, although after very high exposure it can develop in minutes with extremely poor prognosis.
Oedema fluid, usually frothy, is secreted from the bronchi, and may leak from the mouth and the nostrils. At very high levels of exposure, death occurs in minutes to hours from respiratory failure, hypoxaemia, hypovolaemia, acute respiratory obstruction, alveolar destruction or a combination of these.
Acute pulmonary hypertension, pulmonary vascular congestion, and burns of the upper and proximal lower airways contribute. Hypoxia and hypotension indicate a poor prognosis, as does development of pulmonary oedema within four hours of exposure.
Chronic exposure to relatively low levels of chlorine gas tends to cause chronic low-level symptoms - particularly:. Chlorine gas is heavier than air, so it would settle in low-lying areas.
How chlorine works The extent of poisoning caused by chlorine depends on the amount of chlorine a person is exposed to, how the person was exposed, and the length of time of the exposure. When chlorine gas comes into contact with moist tissues such as the eyes, throat, and lungs, an acid is produced that can damage these tissues. Immediate signs and symptoms of chlorine exposure During or immediately after exposure to dangerous concentrations of chlorine, the following signs and symptoms may develop: Blurred vision Burning pain, redness, and blisters on the skin if exposed to gas.
Skin injuries similar to frostbite can occur if it is exposed to liquid chlorine Burning sensation in the nose, throat, and eyes Coughing Chest tightness Difficulty breathing or shortness of breath. Thesemay appear immediately if high concentrations of chlorine gas are inhaled, or they may be delayed if low concentrations of chlorine gas are inhaled.
Fluid in the lungs pulmonary edema that may be delayed for a few hours Nausea and vomiting Watery eyes Wheezing Showing these signs or symptoms does not necessarily mean that a person has been exposed to chlorine.
What the long-term health effects are Long-term complications may occur after breathing in high concentrations of chlorine. Complications are more likely to be seen in people who develop severe health problems such as fluid in the lungs pulmonary edema following the initial exposure. How people can protect themselves, and what they should do if they are exposed to chlorine Leave the area where the chlorine was released and get to fresh air.
Quickly moving to an area where fresh air is available is highly effective in reducing exposure to chlorine. If the chlorine release was outdoors, move away from the area where the chlorine was released.
Go to the highest ground possible, because chlorine is heavier than air and will sink to low-lying areas. If the chlorine release was indoors, get out of the building. If you think you may have been exposed, remove your clothing, rapidly wash your entire body with soap and water, and get medical care as quickly as possible.
Removing and disposing of clothing: Quickly take off clothing that has liquid chlorine on it. Any clothing that has to be pulled over the head should be cut off the body instead of pulled over the head. If possible, seal the clothing in a plastic bag. Then seal the first plastic bag in a second plastic bag. Removing and sealing the clothing in this way will help protect you and other people from any chemicals that might be on your clothes. If you placed your clothes in plastic bags, inform either the local or state health department or emergency personnel upon their arrival.
Do not handle the plastic bags. These symptoms may include :. Diagnosing chlorine poisoning is usually straightforward as symptoms develop rapidly after ingestion or inhalation of the chemical. If the poisoning is due to chlorine gas, leave the area immediately and move somewhere where there is clean air, which may mean going outside.
If chlorine has contaminated skin or clothing, remove the clothing and wash the entire body with soap and water. For burning eyes or blurred vision, rinse the eyes thoroughly with clean water and remove any contact lenses. If a person has swallowed chlorine, do not drink any fluids or attempt to force the chlorine out by vomiting.
Doctors usually treat people with chlorine poisoning in the hospital emergency department. There is currently no antidote for chlorine exposure. Treatment focuses on removing the chlorine from the body as quickly as possible, which may involve the use of medication or activated charcoal.
This procedure involves inserting a tube through the nose or mouth and down into the stomach. The doctor then uses suction to drain the contents of the stomach through the tube. A person with chlorine poisoning may also require further hospital care to treat symptoms and support breathing.
Chlorine poisoning can be severe, even with proper medical care. The outlook will depend on the amount and type of chlorine exposure, and how soon a person receives treatment. It is possible to prevent chlorine poisoning by handling chlorine-based products with extra care, including:. Many industrial and household products contain chlorine, including bleaches, cleaning products, and water purification tablets. Although chlorine is a highly toxic chemical, it is safe when handled correctly. Chlorine exposure can cause serious harm.
If a person shows signs or symptoms of chlorine poisoning, call the emergency services immediately and await their advice before taking further action. If possible, however, the individual should move to a safe area, remove any contaminated clothing, and wash their skin. The outlook depends on the amount and type of chlorine exposure and how rapidly the individual receives medical care. Chemicals used as cooling agents in refrigeration and air-conditioning units can be deadly if inhaled.
0コメント