Q. Is paraquat poisonous to people? With which substances can paraquat be compared?
A. Like many readily available chemicals, paraquat is harmful and fatalities have occurred when the concentrated product has been swallowed in sufficient quantity, usually in an attempt to commit suicide. The label for products containing paraquat states that the product should always be kept in its original container and never stored in food, drink, or other containers. Products containing paraquat should also be locked away when not in use.
In order to ensure that people handling paraquat are aware that it contains chemicals that should be used exclusively for the control of weeds, paraquat formulations manufactured by Syngenta (the leading manufacturer of paraquat) have been given three 'safening' agents to avoid accidental ingestion and to deter misuse: a blue dye, an alerting agent (a strong and deterring odor), and an emetic (to induce vomiting). It is widely believed that these developments have contributed to a reduction in accidents.
The WHO International Program for Chemical Safety classification system of pesticides classifies over 500 chemicals.
| Class | Number of AIs |
|---|---|
| “Extremely hazardous, class Ia” | 29 |
| “Highly hazardous, class Ib” | 61 |
| “Moderately hazardous, class II” | 123 |
| “Slightly hazardous, class III” | 122 |
| “Unlikely to present acute hazard” | 246 |
Paraquat is classified as “moderately hazardous” (WHO class II) along with more than 100 other AIs. Information about the full classification system is available here: