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Brazil - Final Regulatory Action
Phorate CAS number:
Date circular:

Chemical name: Phosphorodithioic acid, O,O-diethyl S-[(ethylthio)methyl] ester

Final regulatory action has been taken for the category: Pesticide

Final regulatory action: The chemical is Banned

Use or uses prohibited by the final regulatory action:

All uses.

Pesticide use or uses that remain allowed:


The final regulatory action was based on a risk or hazard evaluation: Yes

Summary of the final regulatory action:

Prohibition of all technical and formulated products based on phorate active ingredient. So, the production, use, trade, import and export of phorate had been banned.

The reasons for the final regulatory action were relevant to: Human health

Summary of known hazards and risks to human health:

Phorate was an insecticide authorized in Brazil exclusively for agricultural se in cotton, potato, coffee, beans and corn. In 2008 Brazilian Health Surveillance Agency (ANVISA) initiated the toxicological reassessment of phorate due to evidences of high acute toxicity and neurotoxicity of this active ingredient of pesticides.
Brazilian law predicts that pesticides may have their registrations cancelled in the country when they fall under the following conditions related to human health: when they have no antidote or effective treatment in Brazil; if found teratogenic, mutagenic or carcinogenic; if they cause hormonal disturbances and damage to the reproductive system or if they are more dangerous to humans than demonstrated with laboratory animals.
Phorate and its metabolites are easily absorbed through skin and mucous membranes and irreversibly block the catalytic activity of acetylcholinesterase (AChE), the enzyme responsible for mediating the hydrolysis of acetylcholine in acetic acid and choline acid. Thus, they interrupt the transmission of nerve impulses in the cholinergic synapses of the central nervous system (CNS), autonomic nervous system (ANS) and neuromuscular junction. Inactivation of AChE causes cholinergic hyperstimulation by the acetylcholine accumulation in the synaptic cleft.
Phorate is considered one of the most toxic organophosphate AChE inhibitors, with mean oral LD50 for mice ranging from 1.4 to 10 mg/kg body weight.
Phorate can cause complex clinical manifestations in humans, such as encelopathy, intermediate syndrome and polyneuropathy, described by various authors (Young, Jung; Ayer, 1979; Kashyap et al., 1984;. WHO/FAO, 1988; Kusic et al.,1991; Dobozy, 1998; Das and Jena, 2000; Thanal, 2001; Jayakumar, 2002; Mission, 2006; Peter; Prabhakar; Picharnuthu, 2008 a; 2008 b).
However, in laboratory animals that received phorate there were no cases of intermediate syndrome or late polyneuropathy, what shows this pesticide is more toxic to humans than demonstrated in tests with laboratory animals, a prohibitive criterion for registration of pesticides in Brazil.
Besides its neurotoxic effects, phorate demonstrated potential to cause adverse effects to the endocrine regulation processes of steroid hormones in humans (Usmani, 2003), which may contribute to increased cancer case (Alavanja, et al., 2002; Mahajan et al., 2006; Koutros et al., 2010).
With regard to human exposure Usha and Harikrishnan (2004) reported several cases of acute poisoning in communities of Kerala, India. Among these cases, 5 of them, occurred between 1999 and 2002, are associated to exposure to phorate. According to the authors, in July 1999, about 12 people living in banana crop areas were severely poisoned by phorate.
After the product use, it rained on the region, causing the product evaporate quickly and spread to nearby area, reaching the homes. Shortly after application of the product, the symptoms appeared and the affected required hospitalization. In June 2001, a 16 year-old boy died as a result of occupational exposure to phorate for a period of one week. That same year, 40 rural women workers in a tea plantation were intoxicated during harvesting,
Symptoms appeared within 30 minutes after exposure, featured by light-headedness, dizziness, blurred vision, vomiting. Thirty seven women had more severe and remained hospitalized for two days. The authors point out that in July 2002, 31 children from an upper primary school were poisoned by phorate applied in plantation nearby school.
The children showed persistent headache, chest pain, breathing difficulty, nausea, giddiness, blurring of vision and stomach pain, and one of them showed uncontrolled muscle twitching and convulsions even after 24 hours of treatment.
On 21 July 2006, 20 residents of Salkiana village, district Jalandhar, India, had to be rushed to a hospital when neurotoxic symptoms of acute exposure to phorate were observed, the product was used in a nearby sugarcane field. The worst affected were the school children of an Elementary School. Teachers and Students started complaining of a strange smell and breathlessness, suddenly one student fell unconscious and then students started to faint. Within ten minutes, 16 students fainted after inhaling something that was toxic, In addition to difficulty breathing, the most frequent symptoms were poorly being, headache, eye irritation, dizziness, nausea, vomiting, lacrimation, salivation excessively muscle cramps and pain, Six days after exposure to phorate, several patients still had symptoms such as eye irritation, dermal reactions and general uneasiness. (Mission, 2006),
Several studies show that agricultural workers exposed to phorate are victims of poisonings and deaths related to toxicity characteristics of the active ingredient. The exposure becomes even more dangerous due to the difficulties relating to the availability and/or inefficiency of PPE, Moreover, this various social issues (low education, low income) and biological (age and gender) are factors that increase the risk and severity of poisoning caused by this organophosphate.
Therefore, from the re-evaluation of the health effects of phorate, completed in 2015, ANVISA concluded this active ingredient of pesticides has the potential to cause hormonal disturbances in humans and is more toxic to humans than demonstrated in tests with laboratory animals, which are prohibitive criteria for registration of pesticides in Brazil.
Phorate was banned in Brazil on March 16, 2014, where it was no longer marketed since 2011.

Expected effect of the final regulatory action in relation to human health:

Eliminate the risks posed by phorate.

Date of entry into force of the final regulatory action: 16/03/2015