Paraquat or Gramaxone

The Profile of Toxic Danger

Philippe Descamps



Paraquat, one of whose commercial names is Gramaxone, is the number one cause of pesticide poisoning in the country.


Pesticides kill more than just pests: according to the World Health Organization (WHO), every year some 220,000 people around the world die of pesticide poisoning, while another three million suffer acute pesticide poisoning. Although 80% of the pesticides produced are used in developed countries, poisoning cases are proportionally higher in developing countries.

Costa Rica is not immune to this problem: 827 cases of acute pesticide poisoning were reported in 1997. Paraquat, better known here by its brand name Gramaxone, is responsible for the single greatest number of these poisonings. Nationally, 23% of the total of pesticide poisonings is due to this product. Moreover, if we analyze the data from the Atlantic coast province of Limon, we find the incidence of accidents with Paraquat is even higher – 91 cases of a total of 305 – or 30% of all poisonings.

It is an unquestionable fact that Paraquat is the pesticide which causes the largest number of poisonings in Costa Rica. Paradoxically, this herbicide, which is most commonly used nationally in agriculture as well as in the patios of homes, schools, churches and other public places, is classified as "moderately toxic" - yellow label- and is considered not very dangerous to the general population. Considering this reality, it is very pertinent to dedicate a space to discuss Paraquat and to point out the danger that it signifies to the health of the population.


Paraquat’s profile

Paraquat is one of the "Dirty Dozen": a list of dangerous pesticides whose use should be prohibited according to the World Health Organizations (WHO) and the Pesticide Action Network (PAN). This pesticide is prohibited in various Scandinavian countries, and its use is restricted in the United States. In the U.S., the Environmental Protection Agency (EPA) has classified it among the products that are possibly carcinogenic for human beings.

Paraquat is a highly toxic product for human beings. Many cases of acute poisoning and death have been reported caused by Paraquat. When Paraquat is ingested, burns are produced in the mouth and throat; this is followed by a serious irritation of the gastro-intestinal tract which provokes abdominal pain, nausea, vomiting and diarrhea. Other symptoms are thirst, shortness of breath, an accelerated heart rate, lesions in the kidneys, liver, and heart and bleeding in the lungs. Generally, healthy skin doesn’t absorb this product, but bruised or irritated skin can absorb it very easily.

There are two reasons why poisonings from Paraquat are very serious. First, there is no known antidote or effective treatment for poisoning from this product. Secondly, some symptoms can appear a number of days after contact with the pesticide.

In spite of the statistics, Zeneca (the product’s manufacturer), agrochemical distributors, as well as many agronomists and other scientists continue to say that Paraquat isn’t dangerous if it is used correctly. They affirm that due to Paraquat’s blue color, its unpleasant odor and the additive which provokes vomiting when swallowed, that accidental poisoning with the product is impossible.

In Costa Rica, Katherina Wesseling, a scientist from the Regional Institute for Research on Toxic Substances (IRET), of the National Autonomous University (UNA), has carried out a number of investigations on accidental poisonings caused by this herbicide. These investigations have pointed to important findings, among those the fact that slight wounds to the skin, including those that are barely perceptible, can allow for penetration of the pesticide into the body, which can cause grave consequences, including death. Another important observation from these studies is that protective clothing does not impede contact between the pesticide being applied and the skin. Dr. Wessling underlines that even diluted in solution, Paraquat can cause fatal accidental poisonings, and that the only way to eliminate the risks of such poisoning is to not use this product.

The Foro Emaus shares this opinion and is promoting a campaign for the prohibition of Paraquat’s use in Costa Rica. Paraquat is not a substance essential to agricultural production. Thousands of organic and traditional producers farm effectively without the use of herbicides since simple and inexpensive weed control alternatives already exist. As far as conventional agriculture is concerned, this product may be substituted by others that are less dangerous -although, always representing a danger to health. Many agricultural businesses no longer use Paraquat.


18 Reasons (with scientific support) to not use Paraquat

  1. Paraquat has caused the accidental death of many agricultural workers in Costa Rica and worldwide.
  2. No antidote or effective treatment exists to reverse poisoning by Paraquat.
  3. Paraquat causes death after an agony that is sometimes long and always painful.
  4. Paraquat is the agrochemical responsible for the greatest number of poisonings in Costa Rica.
  5. Compared to other agrochemicals, poisonings by Paraquat require long and very costly medical recuperation.
  6. Due to the manner that Paraquat is used in agriculture, it can cause death even when used in small doses and low concentrations. Moreover, it is virtually impossible to take all the necessary precautions to avoid contact with the product.
  7. However sophisticated and clean the protective equipment, it can not guarantee that there will be no exposure to the product.
  8. Paraquat belongs to the "Dirty Dozen" list published by the global "Pesticide Action Network" (PAN). Because of the hazards involved, its use is prohibited in various countries while other countries have put significant restrictions on its use.
  9. Almost 70% of the Paraquat sold in Costa Rica is used by small and medium producers. This is the sector of the population that is most vulnerable:
  1. Scientists in Costa Rica and other parts of the world have come to the conclusion that the use of Paraquat in banana plantations can not be considered safe, and that it would be in public interest to restrict its use in developing countries, including Costa Rica.
  2. There is proof that in the long term Paraquat has negative health effects, especially on the lungs.
  3. Paraquat that is absorbed into the soil has a very long half life.
  4. Public opinion is more and more concerned about the negative consequences on health and the environment which are caused by the use of pesticides.
  5. Banana companies can not achieve the "Better Banana" seal if Paraquat is used on their plantations.
  6. Poisoning with Paraquat in dilute or small doses causes symptoms that are difficult to pinpoint, and which are easily confused with benign symptoms making its treatment difficult. Due to the limited data about poisoning with Paraquat in small doses and low concentrations, the medical establishment has found it difficult to diagnose these accidents.
  7. The majority of the deaths caused by Paraquat occur in developing countries due to inadequate precautions when handled and its unrestricted sale.
  8. Paraquat can be substituted by simple, inexpensive techniques that imply minimal risks for workers.
  9. Imposition of restrictions on the sale of Paraquat is not an adequate measure for avoiding accidents.