Hydrogen phosphide poisoning results from inhalation of fumigants, causing a severe intoxication reaction. Hydrogen phosphide (PH3) is found mainly in pesticides used to control pests, along with magnesium phosphide and aluminum phosphide.
What is hydrogen phosphide poisoning?
Synonyms are phosphine poisoning and phosphorus poisoning. Other names include monophosphine and phosphane. Technically impure acetylene and ferrosilicon are considered the main sources of poisoning. Both agents, when combined with moisture, form hydrogen phosphide and arsine, which cause irritation of the lungs and act as a central neurotoxin. Inhalation causes hydrogen phosphide to form in the body, which can lead to hydrogen phosphide poisoning. PH3 develops in metabolism through magnesium phosphide or aluminum phosphide, blocking important enzyme systems in the body. A high concentration of PH3 results in meta-hemoglobin formation of up to thirty percent. In low doses, the body breaks down the unwanted toxin via phosphorous acid or phosphate.
Causes
Hydrogen phosphide is a severe metabolic poison with inhibition of vital cellular enzymes. Poisoning occurs by inhalation. Repeated episodes of poisoning occur, especially with improper use of pesticides or PH3-containing acetylenics. Phosphoric acid residues can also be found in plasticizers, paints, varnishes, solvents, warfare agents, and plastics. Some workers also come into contact with hydrogen phosphide through the performance of their job duties. However, hydrogen phosphide poisoning happens regularly due to improper use of the hazardous materials. Another cause can be poisoned groundwater due to improper disposal of hazardous substances by companies. Hydrogen phosphide is used in Germany as a fumigant to kill stored food pests in containers and storage areas, and to treat dry foods such as spices, coffee, cocoa, oilseeds, dried fruit, and stored grains. The use of PH3 is not permitted for organic land-based production. Therefore, small amounts of phosphine residues may be present in conventionally produced foods. No poisoning illness in the acute or secondary sense has occurred to date as a result of the consumption of foods contaminated with phosphine residues. The dose contained in the contaminated foods is too low to have a lethal effect. Chronic illnesses clearly attributable to phosphine residues have also not been demonstrated to date. Chronic poisoning due to long-term exposure is not known, since the small doses that people may ingest through their environment are too small to cause acute symptoms of poisoning. These small amounts are excreted by the organism after some time. There are different phosphorus substances: red, considered relatively non-toxic, black, also not highly toxic, white, lethal dose from 0.05 grams of poison absorption through the skin. The substance is colorless, but not odorless. It emits an extremely unpleasant odor reminiscent of rotten meat, garlic and carbide.
Symptoms, complaints and signs
Intoxication symptoms are divided into acute and subacute poisoning. If a patient suffers from acute symptoms of poisoning from hydrogen phosphide, they can lead to death immediately. These severe concomitant symptoms lead to exitus within 24 to 48 hours due to asphyctic manifestations and pulmonary edema, accompanied by respiratory failure and maximally dilated pupils. The symptoms of subacute poisoning are often not immediately apparent. Often, the focus is on complaints of the gastrointestinal tract, such as nausea, vomiting, and diarrhea. Other symptoms of poisoning affect the central nervous system with dullness, headache, abdominal pain, fainting, ringing in the ears, dizziness, sweating, and numbness. But also disturbances of consciousness, unsteady gait and states of agitation can occur. At times, cyanosis, heart failure, tachycardia, high-grade shortness of breath with difficult inspirium (inhalation phase), feeling of pressure and burning pain behind the sternum, in the diaphragm area and in the back are noted. Fumigants primarily have a lasting effect on the respiratory system.Metabolism is secondarily affected by exposure to hydrogen phosphide with negative effects on the brain, kidneys and liver. 0.01 mg/liter of air is lethal to the human organism after six hours of exposure. Amounts of hydrogen phosphide that are not dangerous in themselves may well have a more cumulative effect with repeated inhalation.
Diagnosis and course of the disease
The complete picture of poisoning is not characteristic at first, but occurs in many forms. Often, hydrogen phosphide poisoning is confused with food poisoning because the accompanying symptoms are similar. The findings on dissection are uncharacteristic. There are patients who show no pathologically-anatomically recognizable symptoms. Cardiac dilation, pulmonary edema, blood overfilling in the liver and kidneys are the main signs of poisoning by PH3. The blood is more fluid than normal and very dark. Except for hyperemia of the lungs, kidneys, brain, and trachea, only occasional minor hemorrhages occur in the myocardium. The kidneys show opacified swelling of the renal tubules. The clinical findings of phosphorus poisoning and hydrogen phosphide poisoning are congruent.
Complications
Hydrogen phosphide poisoning often has dramatic consequences. However, it depends on the concentration of the poison that the body comes into contact with. Hydrogen phosphide can be absorbed through the skin or the respiratory tract. If a higher concentration than 0.05 grams of hydrogen phosphide enters the organism, the poisoning is always fatal after six hours of exposure. However, even at lower concentrations, life-threatening complications can occur. Acute poisoning is characterized by respiratory paralysis and severe damage to the kidneys, liver and lungs. Pulmonary edema may develop, leading to respiratory failure with fatal outcome. Other symptoms of poisoning affect the central nervous system. Cardiac arrhythmias, shortness of breath, increased pulse and impaired consciousness up to coma may occur. Acute hydrogen phosphide poisoning is always a highly life-threatening complication. However, hydrogen phosphide poisoning can also occur subacutely. In these cases, the body is indeed only exposed to low concentrations of the poison. But with frequent exposure to low concentrations of hydrogen phosphide, the poisonous effect accumulates. Eventually, even then, severe damage to the brain, liver and kidneys can occur, causing long-term health problems. Furthermore, chronic hydrogen phosphide poisoning often also results in pulmonary edema with severe breathing difficulties and heart failure, which can also lead to fatal complications.
When should you see a doctor?
If the affected person notices sudden irregularities inside the body due to inhalation of gases or other environmental factors, this is an alarming sign. If there is dizziness, malaise, or internal weakness, medical attention is needed. If loss of consciousness occurs, emergency medical services must be alerted. In case of respiratory arrest, bystanders should provide first aid if they are able. Unsteady gait, numbness, coughing, and interruptions in breathing must be presented to a physician. Sweating, hot flashes, rapid heartbeat, and a sensation of pain in the body should be evaluated by a physician. Headaches, nausea as well as vomiting are other signs of health impairment that should be clarified. Burning pain, dilated pupils as well as struggling for oxygen are worrisome. If the affected person was exposed to chemical poisons or substances, immediate attention should be paid to adequate fresh air as well as ventilation. Windows and doors should be opened if the person is indoors. Without immediate adequate medical attention, the affected person may die. Balance disturbances, a loss of the usual muscle strength as well as disturbances of the hearing are alarm signals of the organism. A doctor is needed so that treatment can be initiated. Since in the case of hydrogen phosphide poisoning the concentration of the poison is decisive for the further course, the affected person must be removed from the danger zone as quickly as possible.
Treatment and therapy
Patients exhibiting clear, as well as less clear, symptoms of PH3 poisoning should be immediately transferred to emergency medical services, who will ensure vital signs and initiate immediate decontamination measures. Prior to hospitalization, individuals at the scene initiate first aid measures. They must induce the patient to vomit and immediately give him plenty of fluids. In doing so, first aiders must ensure that they do not come into contact with the excrement, as hydrogen phosphide is also absorbed through the skin. Wetted clothing must be removed immediately. If the eyes are affected, they must be rinsed with plenty of water. In the emergency room, physicians rinse the patient’s skin and/or eyes with a three- or five-percent solution of sodium bicarbonate and chloramine T, respectively. After all emergency measures have been taken, the patient needs warmth, rest and darkness. In addition, he is ventilated.
Outlook and prognosis
The prognosis after hydrogen phosphide poisoning depends on the degree of exposure to the toxin. It is a toxic fumigant used to protect storable foods. Because of its severe toxicity, this fumigant should only be used by properly trained professionals. However, fumigant residues often occur in sea containers. Poisoning with hydrogen phosphide can occur inhalationally – for example, when a sea container is fumigated -, or through skin contamination. Inhalational hydrogen phosphide poisoning must be treated immediately as an emergency. Typical symptoms of poisoning may occur as a result of hydrogen phosphide poisoning. In case of larger inhaled quantities, or prolonged exposure, the organism can no longer excrete the ingested poison on its own. If the subsequent symptoms of poisoning, such as vomiting after nausea, sudden drowsiness and convulsions, are not immediately treated with intensive medical care, the victim of poisoning is in the worst case threatened with death. Low exposures to residues on fumigated fruits and vegetables can apparently be broken down by the body on its own. In this case, the prognosis is much better to get away without permanent damage. In Germany, only some preparations with a certain hydrogen phosphide content are approved for the fumigation of conventionally produced food. These fumigation preparations may be used, for example, for coffee or cocoa shipments, dried fruit or seeds containing fat, legumes and larger grain shipments.
Prevention
Hydrogen phosphide should only be applied by trained personnel, as it is highly toxic in its pure state, and is also corrosive, harmful to the environment, and highly flammable. In combination with oxygen, spontaneous combustion may occur. Safety regulations must be observed at all times. Prevention in the clinical sense is not possible, but only proper handling is indicated.
Aftercare
In some cases, hydrogen phosphide poisoning leads to damage of body organs. Thus, the lungs, liver, or kidneys are often affected. This results in further diseases that require treatment. Aftercare then provides suitable support in everyday life. At the end of the hospital stay, the patient is usually referred to a physician in private practice, who takes over the further follow-up. The extent of this depends on the level of symptoms. Medication is often administered. In some cases, a stay in the clinic is followed by rehabilitation. There, the patient is specifically prepared for a return to everyday life at work and at home. Aftercare also aims to prevent the recurrence of the disease. However, since hydrogen phosphide poisoning is an acute and accidental event, this aspect cannot be the responsibility of a physician. Instead, individuals must take appropriate protective measures themselves to avoid suffering hydrogen phosphide poisoning. If necessary, the physician will provide information on appropriate measures. Since hazardous contact is usually only possible in everyday working life, it is essential to comply with the safety regulations applicable there. The employer must provide protective equipment to ensure proper handling.
What you can do yourself
In everyday life, the cleaning and pest control products in your own household or garden must be checked regularly.As a matter of principle, they should be kept out of reach of children and checked for their ingredients. If existing products contain hydrogen phosphide, it must be checked whether these articles are required due to their effect on the human organism. In addition, they must be labeled accordingly so that there is no risk of confusion. If the products are needed, care must be taken in their use. Mouth protection should be worn and the affected person should take care not to handle the pesticides indoors. Affected individuals should obtain detailed information about the mode of action of hydrogen phosphide through the media or the manufacturers of the products. All people who also have access to the products should be fully educated by the owner and should be made aware of the hazards. It is also helpful to obtain information in advance about the correct behavior in the event of poisoning. If the affected person comes into contact with hydrogen phosphide as a result of an occupational activity, daily compliance with occupational safety regulations is necessary. When preparing meals, fresh fruit, vegetables or spices should always be rinsed with fresh water and cleaned before processing. Consumption of food that has not been cleaned should always be avoided.
