Farming 3: Chemical Exposures Portal
Anhydrous Ammonia
Anhydrous ammonia is a colorless, non-flammable, liquefied gas most commonly used to fertilize crops. Its odor is similar to household ammonia. Anhydrous means without water. The vapor of anhydrous ammonia seeks to attach to water sources, such as oral mucosa, eyes, respiratory tracts, and skin. It is stored in specially designed tanks and injected into the ground. Farmers can be injured when hoses break or leak, or there is a valve leak on the tank. Anhydrous ammonia under pressure in a holding tank can spray out, often injuring eyes, face, respiratory tracts, and skin. Patients develop severe chemical burns and often complain of burning and stinging sensations. Many vomit from the exposure. The smell can be detected at 3 parts per million (ppm), and the dangerous level is 300 ppm. In high concentrations, anhydrous ammonia may cause respiratory spasms and uncontrolled coughing.
Other potential ways someone can be exposed to anhydrous ammonia:
- Methamphetamine recipes where anhydrous ammonia may be included
- Train derailments with anhydrous ammonia spillage
- Leakage at plant or tanks where anhydrous ammonia is stored
- Ingestion
Four Mechanisms of Anhydrous Ammonia Injuries
- Dehydration of body tissue—Anhydrous ammonia pulls water from tissues.
- Caustic burning—Anhydrous ammonia combined with water forms ammonium hydroxide. Ammonium hydroxide is very caustic to body tissues, resulting in burns to any tissue that it comes in contact with. This may result in blindness, skin burns, and damage to the respiratory tract and lungs.
- Freezing—Body tissue freezes almost immediately when exposed to the liquid form of anhydrous ammonia. Anhydrous ammonia comes out of pressurized tanks at minus 60ºF. As it combines with water, its coldness freezes the tissue. Heat is pulled from the surrounding tissues. Frostbite-like injury then occurs.
- Ingestion forming methemoglobinemia—High concentrations of ammonia can leach from the soil into the farm water supplies. When consumed, this can give rise to high nitrate levels that may produce life-threatening methemoglobinemia, especially in infants.
Signs and Symptoms
- Respiratory distress and coughing, mucosal burns, pulmonary edema, laryngospasm, chemical pneumonitis
- Increased blood pressure and pulse
- Lacrimation, iritis, and temporary blindness (Eyes may have a sensation like ice picks or acid being stuck into them.)
- Nausea and vomiting
- Burns and frostbite
Treatment
- Rescuers and health care providers need to be protected from the liquid and vapor ammonia.
- Remove the patient from the anhydrous ammonia source.
- Remove all contaminated clothing.
- Administer humidified oxygen to help injured airway passages replace water.
- Irrigate with water for a minimum of 20 minutes to decontaminate the skin and mucous membranes as needed.
- For respiratory distress, intubate with O2 at 100%; give bronchodilators.
- Separate affected digits by gauze and elevate.
- Patients shouldn’t bear weight on affected extremities.
- Prehospital workers who may have been exposed need decontamination and may need treatment.
- If methemoglobinemia develops in a patient who has ingested the ammonia, the treatment of choice is methylene blue, 1 to 2 mg/kg as a 1% solution given slowly over 5 minutes.
Organophosphates
Farmers frequently utilize herbicides, rodenticides, fungicides, and insecticides. These chemicals are used to destroy, prevent, or control weeds, rodents, fungus, and insects to protect valuable crops. These chemicals often contain organophosphates. Fatal exposures have resulted from ingestions, inhalation, and dermal absorption. Toxicity is expressed in terms of lethal dose (LD). LD50 is one way to measure the short-term poisoning potential or acute toxicity of a chemical. LD50 is the amount of chemical given at once, which causes death in 50% of a group of test animals.*
Life-threatening exposure to organophosphates may occur even during simple
tasks. An example would be a farmer burning herbicide bags, inhaling fumes, and then suddenly collapsing. All
types of clothing absorb organophosphates, so remove and decontaminate
clothing to prevent further exposure.
PEDS: Remember, many exposures involve children.
Presenting symptoms may occur from within just a few minutes to 12 hours post exposure. Organophosphates are lipid soluble so patients will develop muscarinic symptoms first and then progress to nicotinic and CNS symptoms. Hypersecretion occurs due to hyperactivity of the gut and the bronchial muscles. Patients secrete copious amounts of fluids from e very orifice. See mnemonic DUMBBBELS under Symptom Recognition Effects on the brain may produce staggering gait, severe tremor, and a psychosis that may be mistaken for alcohol intoxication.
Quick recognition of symptoms is necessary to reverse cholinergic effects. Sudden unconsciousness may be attributable to heat exhaustion, but may potentially be a result of organophosphate exposure. Miosis and muscle twitching are symptoms not seen with heat exhaustion but seen with organophosphate exposure.
Symptom Recognition for Organophosphate Toxicity
To recognize symptoms, use the mnemonic DUMBBBELS
Muscarinic Symptoms—DUMBBBELS
- Diarrhea
- Urination
- Miosis
- Bronchorrea
- Bronchospasm
- Bradycardia
- Emesis
- Lacrimation
- Salivation
As the chemical gets deeper into the tissue, the patient will develop nicotinic symptoms.
Nicotinic Symptoms (note the Monday - Friday memory trigger)
- Mydrias
- Tachycardia
- Weakness, smooth muscle paralysis
- tHypertension
- Fasciculations
The tachycardia and bradycardia may manifest to look like a sick sinus syndrome on the monitor or on ECG.
As weakness and diaphragm paralysis develops, the lungs will pool with fluids and oxygen exchange will decrease so that intubation may be necessary.
CNS Symptoms – Headaches, Ataxia, Confusion, Seizures, Coma
With any chemical exposure, contact the Regional Poison Control System @ 1-800-222-1222. Provide necessary information, such as chemical trade name, brand name, or common name.
Other useful information from labels
- Classification of what chemical is used for
- Active ingredients and container contents
- Warning signs and child, animal, environmental and physical hazard warnings.
- Precautionary statements
- Practical treatments and first aid
- EPA registration number if established.
Initial Treatment
- Protect yourself
- Remove the patient’s clothes.
- Decontaminate the patient.
- Intubate the patient, if needed.
- Obtain IV access.
- Obtain an ECG.
- Medications. Atropine blocks the action of acetylcholine. 2-PAM treats the muscle weakness and blocks the action of acetylcholine but atropine is cheaper and more readily available to start treatment. Atropine may be given up to 1 to 2 grams in severe cases. Give until mucus membranes are dry.
For more information on treatment, see Vol III—TOX18 Organophosphates.
References
- Minnesota Department of Agriculture, Agronomy and Plant Protection Division. Hazards of Anhydrous Ammonia When Used in the Illegal Production of Methamphetamine, January 2000. Available at: www.mda.state.mn.us Accessed on: January 17, 2005.
- Toxic Effect of Agriculture, Emergency Medicine, February 15, 1989, p. 151-161.
- Shutske, John M. Using Anhydrous Ammonia Safely on the Farm. Available at: http://www.extension.umn.edu/distribution/cropsystems/DC2326.html. 2002 Accessed on: January 17, 2005.
- Vasil, EF. Pesticide Poisoning, Emergency Medical Services, Volume 18, Number 8, September 1989, p.58.