Highly hazardous pesticides (HHPs) are defined by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) as pesticides that are acknowledged to present particularly high levels of acute or chronic hazards to health or environment according to internationally accepted classification systems such as the WHO Recommended Classification of Pesticides by Hazard, or Globally Harmonized System of Classification and Labelling of Chemicals, or their listing in relevant binding international agreements or conventions (Stockholm or Rotterdam Conventions, Montreal Protocol). In addition, under Criterion 8, pesticides that appear to cause severe or irreversible harm to health or the environment under conditions of use in a country may be considered to be, and treated as, highly hazardous.
There is no single international list of HHPs because pesticides falling under criterion 8 will differ by country according to the conditions.
Ingestion of HHPs for self-harm is much more likely to result in death than ingestion of a non-HHP pesticide.
FAO/WHO Joint Meeting on Pesticide Management. International Code of Conduct on Pesticide Management. Guidelines on Highly Hazardous Pesticides. http://www.fao.org/3/a-i5566e.pdf
Globally Harmonized System of Classification and Labelling of Chemicals http://www.unece.org/trans/danger/publi/ghs/ghs_welcome_e.html
WHO Recommended Classification of Pesticides by Hazard. http://www.who.int/ipcs/publications/pesticides_hazard/en/