“Paraquat lung” is a common term for a condition affecting the lungs after exposure to paraquat dichloride, a chemical herbicide.
Farmers use Paraquat herbicide to control weeds and grasses before planting crops. It is also used to dry up crops like cotton prior to harvest.
The herbicide is mainly used in agricultural settings, especially on crops such as corn, soybeans, and cotton. Paraquat is typically applied via an aerial crop duster, which sprays the product onto crop fields.
Although Paraquat is a very effective herbicide, it is also highly toxic if ingested or inhaled. Paraquat can even cause adverse effects through skin exposure.
The term “Paraquat lung” arose due to its chemical effects on the lungs of exposed persons.
Products Containing Paraquat
Paraquat was introduced in 1962 under the trade name Gramoxone. Over the years, manufacturers like Chevron Chemical Company, Growmark, and Syngenta have sold paraquat under a variety of brand names. Those brand names include:
- Ortho Paraquat
How Does Paraquat Work?
Paraquat is available as a liquid in various strengths, and as water-soluble dichloride salt particles.
The herbicide is relatively cheap and fast-acting on a wide range of grasses and broad-leaved weeds.
Paraquat is also rain-fast within minutes of application and is inactivated on contact with soil. This means that no biologically active residues remain in the soil, so farmers can plant or sow crops almost immediately after spraying.
Paraquat works well on plants that are resistant to glyphosate (Roundup). This has contributed to Paraquat’s popularity in the U.S.
The herbicide destroys weeds by interfering with the electron transfer process in photosynthesis. This is the process through which green plants use sunlight to synthesize foods from carbon dioxide and water, with oxygen as a by-product.
Paraquat transfers electrons to oxygen in a process known as oxidation and reduction, or “redox.”
The transfer of these electrons produces a “highly reactive superoxide free radical” that “attacks fatty acids in the cell membrane, disintegrating the membrane and tissues,” allowing water to escape from the plant material and causing the plant to die.
A similar process happens in the lungs of people with Paraquat exposure.
Types of Paraquat Exposure
Paraquat is classified by the U.S. Environmental Protection Agency (EPA) as “restricted use.” This means that Paraquat can only be purchased and used by licensed applicators.
People who mix, handle, and apply Paraquat need to wear personal protective equipment (PPE) including protective eyewear, chemical-resistant gloves, and an air-purifying respirator mask.
For safety reasons, Paraquat manufacturers and distributors include an additive that causes a strong odor and an emetic agent to induce vomiting if ingested.
Previous iterations of the chemical were brown in color and were often confused with cola and coffee drinks (leading to accidental ingestion). Newer Paraquat formulations are now a dark blue-green color.
Ingestion is the most common form of Paraquat poisoning. Due to the redox process, Paraquat is quickly absorbed into the bloodstream once ingested. As little as a teaspoon of concentrated Paraquat can result in death due to respiratory failure.
Paraquat poisoning can also occur when the product is inhaled and directly introduced into the delicate lung tissue.
The lung is actually an excellent route for the absorption and distributions of toxic gas particles because of the organ’s large surface area and good blood supply.
Paraquat is also corrosive to the skin, especially for workers who experience prolonged paraquat exposure.
Poisoning through the skin is more common if the chemical comes into contact with an existing cut, sore, or rash.
Paraquat can also severely irritate the eyes, leading to blurred vision and cornea damage.
Symptoms of Paraquat Exposure
Immediately after ingesting or inhaling a toxic amount of Paraquat herbicide, a person experiences swelling and pain in the mouth and throat.
After the initial exposure, a person may experience nausea, abdominal pain, vomiting, and diarrhea. The gastrointestinal symptoms are often severe, leading to dehydration and low blood pressure.
Additional Paraquat poisoning symptoms include:
- Extreme thirst
- Loss of appetite
- Mouth ulcers
- Muscle pain and/or weakness
- Shortness of breath
- Acute respiratory distress
- Rapid heartbeat
- Skin fissures
- Peeling, burns, and blistering
- Nail damage, including discoloration, breaking down of the nail bed, and nail loss
Ingesting a small amount of Paraquat may lead to the following adverse health effects within several days to several weeks:
- Heart failure
- Kidney failure
- Liver failure
- Lung scarring
- Holes or burns in the esophagus
- Respiratory failure
Paraquat exposure in pregnant women also affects the fetus, and is nearly always fatal. Paraquat particles enter the mother’s bloodstream and cross the placenta, affecting the fetus’s lung tissue.
Seek emergency medical attention immediately if you believe that someone has been exposed to Paraquat.
How Does Paraquat Affect the Lungs?
Once exposed, Paraquat is distributed to all areas of the body.
However, the lungs are especially vulnerable. This is because of the high concentration of oxygenated cells in the lungs.
Paraquat particles travel directly to the lung tissue through the bloodstream. In the lungs, Paraquat damages the mitochondria of the lung cells through the production of free radicals in the redox process.
This cell damage leads to oxidative stress, an imbalance between free radical activity and antioxidant activity. Once the redox cycle begins, the damage to the lung cells is difficult to interrupt.
Paraquat damage leads to edema or swelling caused by excessive fluid in the lung tissues.
A few days to a few weeks after ingesting Paraquat, the exposed person develops pulmonary fibrosis. This is when lung tissue becomes damaged and scarred with lesions that make breathing difficult.
High-resolution computed tomography (HRCT) scans are helpful to visualize the lung damage in people with Paraquat exposure.
Normal lungs appear black in an X-ray or HRCT scan. If the patient seeks medical treatment immediately after exposure, initial HRCT scans may reveal no damage in the lungs.
However, within the first few days after exposure, HRCT scans reveal a condition known as “ground-glass opacity” in the lungs. These are gray areas that indicate increased lung density, meaning that something is partially filling the air spaces inside the lungs.
Typically, this gray area is a result of lesions and damaged lung tissue – hence the name “Paraquat lung.”
Treatment and Prognosis for Paraquat Lung
If someone is exposed to Paraquat, they should seek medical treatment immediately.
The timing of treatment is especially crucial for Paraquat poisoning because of the rapid escalation of the redox process and the increased risk of lung damage.
Early medical treatment reduces the risk of permanent side effects from Paraquat poisoning.
Treatment for Paraquat Exposure
People who experience dermal Paraquat exposure, or exposure on the skin, should immediately remove any affected clothing.
They should wash the affected area gently but thoroughly with soap and water to prevent absorption through the skin. (Harsh scrubbing can create a skin abrasion that might increase Paraquat absorption into the bloodstream.)
Exposure through ingestion and inhalation is more difficult to treat. There is currently no antidote for Paraquat poisoning. Treatment options focus on eliminating the Paraquat particles from the affected person’s system.
In some cases, medical professionals will first clean out the contents of the exposed person’s stomach through gastric lavage (pumping the stomach) to reduce further Paraquat absorption into the bloodstream.
Other treatment options include activated charcoal or Fuller’s earth, either taken orally or through a nasal tube. This might help absorb the chemical particles and decrease the amount absorbed in the body.
If the Paraquat poisoning is more advanced, medical staff might attempt hemoperfusion. This is a procedure that attempts to filter blood through charcoal to remove the Paraquat from the system, especially from the lungs.
Medical staff will also provide supportive care such as intravenous fluids, medications to help with breathing and lower blood pressure, antioxidants, a ventilator to support breathing, and possibly dialysis for kidney failure.
Someone suffering from Paraquat exposure is typically not provided with supplemental oxygen. This is because excess oxygen may contribute to the redox process and increase the risk of organ damage.
Prognosis for Paraquat Poisoning
Once a person is exposed to Paraquat, the outlook for their recovery depends on several factors:
- the concentration of the paraquat mixture
- the method of the exposure
- the severity of the exposure
- their overall health at the time of the exposure
- the amount of time between ingestion and the last meal, and
- how quickly they received medical attention.
Ingesting even a teaspoon of Paraquat can be lethal in the right conditions.
Some studies suggest that those who inhale Paraquat have a better chance of survival than those who ingest Paraquat.
People who ingest large amounts of Paraquat are not likely to survive, even with immediate medical treatment.
Someone who was exposed to Paraquat and survived will likely experience breathing issues, and long-term or permanent damage and scarring of the lungs (“Paraquat lung”).
Survivors of Paraquat poisoning may also experience esophagus damage, making it difficult for the person to swallow.
Lung damage as a result of Paraquat exposure may permanently affect the person’s breathing functions.
However, some patients who survive Paraquat exposure showed an improvement in lung function over time.
The results of one study suggest that “Paraquat lung” may not be irreversible or progressive. In fact, some of the patients in this study experienced an increase in lung volume – and improved lung function – 2-3 years after Paraquat exposure.
Do You Have Lung Damage From Paraquat Exposure?
If you or a loved one were exposed to Paraquat herbicide and experienced adverse effects like “Paraquat lung,” you should contact an attorney immediately.
You may be able to seek compensation for damages, including medical costs, lost wages, pain and suffering, and declines in your quality of life.
There is a deadline to file a claim, and lawsuits against Paraquat manufacturers have already been filed in multiple states.
VanDerGinst Law is currently accepting claims against the manufacturers of Paraquat. We offer a free consultation. If you don’t win, you don’t pay. Guaranteed.
We’ll fight to get you the compensation you deserve.