A six-year saga, in which Syngenta sought to overturn Thailand’s ban on the herbicide paraquat and the insecticide chlorpyrifos, has been decided at first instance. The Court upheld the state’s power to impose the ban and found that it had acted lawfully. In a parallel case, however, the same court ordered the Department of Agriculture to pay out more than 116 million baht of public money to compensate the company.

What the case is about

For more than three decades, two agricultural chemicals were used extensively across Thailand.

In 2019 the Hazardous Substances Committee resolved to withdraw both substances from use, reclassifying them from “Type 3 hazardous substances” (permitted under licence) to “Type 4 hazardous substances” — a category under which production, import, export and possession are prohibited outright.

Syngenta Crop Protection Limited, the principal importer, contested the decision and brought two separate actions before the Administrative Court. The litigation ran for six years.

Timeline of key events

• 23 May 2018 The Hazardous Substances Committee resolves to adopt “restricted use” measures for three substances — paraquat, chlorpyrifos and glyphosate. This falls short of a ban.
• 30 June 2019 The Department of Agriculture ceases to authorise further imports of the two substances.
• 22 October 2019 At its 41-9/2562 meeting, the Hazardous Substances Committee resolves to reclassify all three substances as Type 4 with effect from 1 December 2019, and directs that a draft notification be prepared and put out for public consultation.
• November 2019 A 15-day online public consultation draws 48,789 respondents: 12,143 (24.89 per cent) support the ban; 36,656 (75.11 per cent) oppose it.
• 27 November 2019 The decisive vote. At its 1-1/2562 meeting, the Hazardous Substances Committee resolves that paraquat and chlorpyrifos be designated Type 4 hazardous substances with effect from 1 June 2020. Glyphosate is to remain subject only to restricted-use measures.
• 15 May 2020 The Ministry of Industry issues the Notification on the List of Hazardous Substances (No. 6) B.E. 2563, published in the Royal Gazette on 19 May 2020.
• 25 May 2020 The Director-General of the Department of Agriculture issues Department of Agriculture Order No. 750/2563, setting out the recall procedure. Clause 8 states in terms that “the Department of Agriculture shall bear no expense whatsoever” — the provision that would become the central point of dispute.
• 1 June 2020 The ban takes effect. Farmers must return stock to retailers within 90 days; retailers must return it to manufacturers and importers within 120 days; and manufacturers and importers must submit a disposal plan within 270 days (by 25 February 2021).
• 18 August – 1 September 2020 The Foundation for Consumers and the BioThai Foundation apply to join the proceedings as interveners, and the Court grants leave — a welcome precedent in Thai environmental litigation, allowing civil society organisations to place evidence directly before the Court.
• 15 February – 4 March 2021 The company files its disposal plan and Department of Agriculture officials certify the quantities held. In total, 1,169,840 litres of paraquat are consigned for incineration at Akkhie Prakarn Public Company Limited.
• 7 July 2026 The Central Administrative Court holds its first hearing in the compensation case.
• 31 July 2026 The Central Administrative Court delivers judgment in both cases on the same day.

Case 1 — The Court upholds the ban as lawful

1The notification was issued through a proper procedure

The company argued that because a clear majority of consultation respondents (75 per cent) opposed the ban, the state ought not to have proceeded. The Court rejected the argument, holding that a public consultation is “merely an opportunity for the public and relevant sectors to participate by submitting information for the consideration of the responsible agencies. The views of the public and of the various sectors have no binding legal effect … such that a decision must be taken in accordance with the opinion of the majority of respondents.”

2The Court applies the precautionary principle — the most significant element of the judgment

The precautionary principle holds, in essence, that where there is sufficient indication that something is likely to be harmful, the state need not wait for conclusive proof before acting. To wait for complete certainty is to risk allowing irreversible damage to occur in the meantime.

Notably, the principle is not codified in Thai law. The Court nonetheless read it into the statutory scheme by way of the Constitution.

Summarising the substance of the principle, the Court held that the state is under a duty to exercise care to minimise adverse effects on the public, on communities, on the environment and on biological diversity “even where there is not yet scientific data conclusively establishing the cause and degree of the harm that may befall the public, animals, plants, property or the environment.”

The Court further emphasised that Section 18, paragraph two, of the Hazardous Substances Act “is not directed solely at safeguarding human life and physical safety, but is also intended to protect the animals, plants, property and the environment that exist within that environment alongside human beings.”

3Restricted use was not enough; only withdrawal would do

Before the ban, the state had issued a 2019 Ministry of Agriculture and Cooperatives notification restricting the use of paraquat, prohibiting its application in areas under vegetable or medicinal-plant cultivation, in watershed areas, in public spaces, and in sensitive locations such as schools, hospitals and childcare centres.

The Court found those measures insufficient, since they prohibited use only in certain areas.

4The public interest outweighs the loss to private parties

The Court accepted that the ban would inevitably affect manufacturers, importers, retailers and farmers. Weighing the competing interests, however, it concluded that “the benefit to be derived from such action is the greater.” The exercise of discretion by the Minister, with the concurrence of the Hazardous Substances Committee, was accordingly lawful.

The Court also recorded that “illness among the population resulting from exposure to paraquat and chlorpyrifos will affect the national public health system, which must care for and treat those who fall ill … whether directly or indirectly.”

The evidence of harm recorded in the judgment

The judgment sets out the scientific evidence in considerable detail, drawing on the report of the Extraordinary Committee of the House of Representatives on the Study of Approaches to Controlling the Use of Chemicals in the Agricultural Sector. This is the portion of the ruling most likely to be cited in future proceedings.

Case 2 — The Court orders the state to pay 116.98 million baht

The dispute turned entirely on Clauses 6, 7 and 8 of Department of Agriculture Order No. 750/2563, which required licensed manufacturers and importers to collect stock returned by retailers and farmers nationwide, to store it and to incinerate it, while providing that the Department “shall bear no expense whatsoever.”

The Court’s reasoning: the state had no power to make such an order

Having examined Sections 41, 43 and 52 of the Hazardous Substances Act B.E. 2535 (1992), the Court concluded:

The Court further observed that Section 52, on which the state relied, applies to operators who have contravened the law. This company, by contrast, had operated lawfully throughout, having been incorporated on 26 January 1981. The burden it faced arose not from any wrongdoing but from the state’s decision to eliminate a danger in the public interest. Accordingly, “the plaintiff, having acted in good faith and having been required to bear a burden arising from action taken to preserve the public interest, is entitled to protection by the state. The state may not treat the plaintiff as though it were a person who had contravened the provisions of the law.”

Since the state was well aware that large quantities remained in circulation and that disposal would be costly, yet made no provision for assistance of any kind, the Court held that this imposed an undue burden upon the plaintiff.

How the Court arrived at the figure

Notably, the company had claimed 127,054,070.02 baht, a sum that included transport, storage, packaging and outstanding customer receivables. The Court awarded disposal costs alone, applying the Department of Agriculture’s own estimate on the ground that it constituted “an estimate prepared by state officials directly responsible for the matter, drawn from a database grounded in technical principles and therefore carrying evidential weight.”

Why civil society is concerned

1. A double burden — the public pays coming and going

Prokchon Usap, coordinator of the Thailand Pesticide Alert Network (Thai-PAN), explains that without a ban society bears the external costs of these substances, in medical treatment and environmental damage alike. With the ban in place, taxpayers are now being asked to fund the disposal as well. “It amounts to a double burden,” she said. “That cannot be the right principle.”

Amarin Saichan, a lawyer with the EnLAW Foundation, adds that private companies profited from these sales without contributing to the costs borne by society, and that when the time came to dispose of the stock, public money was called upon. “We lose coming and going,” he observed.

2. Regulators may no longer dare to act

This is the gravest of the concerns. Should the judgment stand as a precedent without accompanying legislative reform, agencies may hesitate before banning the next hazardous substance, for fear of exposure to compensation claims.

It should be borne in mind that the Hazardous Substances Act extends well beyond agricultural chemicals. It covers industrial chemicals, substances used in households and hospitals, and those used in livestock, fisheries and the energy business — with six agencies sharing responsibility for its administration.

“The cost of dealing with banned chemicals,” Mr Amarin emphasised, “must not become a reason to delay or hesitate over which substance may need to be banned next.”

3. There is a genuine gap in the legislation

That the Court and the Department of Agriculture read the statute differently on the question of who must bear disposal costs is itself evidence that the Hazardous Substances Act is inadequately drafted. The point needs to be settled expressly, rather than left to interpretation.

Policy recommendations from civil society

• Amend the Hazardous Substances Act to cover the full process. The polluter pays principle and the principle of extended producer responsibility should be written into the statute expressly, so that they are not left to interpretation.
• Draw on international practice. In the European Union and in South Africa, once a chemical is withdrawn from use it ceases to be a “product” and becomes “hazardous waste”. The manufacturer is then obliged to recall and destroy it forthwith, without shifting the cost onto the state or the public — consistent with the product stewardship principles of the Food and Agriculture Organization of the United Nations (FAO).
• Reverse the burden of proof. At present it falls to civil society and academia to demonstrate that a substance is hazardous. The opposite should apply: an operator seeking to sell a substance should first have to demonstrate that it is sufficiently safe.
• Address the highly hazardous substances that remain. More than 200 substances classified as highly hazardous pesticides under FAO and WHO criteria remain on Thailand’s Type 3 list.
• Monitor glyphosate closely. It was not banned but made subject to restricted use, and import volumes have been rising again in recent years. If use cannot in practice be restricted, the matter should be referred back to the Hazardous Substances Committee.

What happens next

The judgment is not final. It is a decision at first instance, and all parties retain a right of appeal to the Supreme Administrative Court.

• The state. The Department of Agriculture may appeal the compensation award and, under Ministry of Finance regulations, will in all likelihood be required to do so. Civil society organisations agree that the state should contest the ruling, given that the measures were adopted to protect the public interest.
• The company. It remains entitled to appeal and to renew its application for revocation of the prohibition notification.
• The interveners. As parties to the first case, the Foundation for Consumers and the BioThai Foundation may appeal against the revocation of the Department of Agriculture Order, which forms the basis of the compensation award in the second case.

One point warrants close attention: for as long as the matter remains unresolved, interest continues to accrue. Mr Amarin therefore urges the legislature and the responsible agencies to use this opportunity to review and amend the law without delay, rather than waiting for the outcome of any appeal.

Six years on: what Thais have gained, and what they have lost

Mr Amarin concluded that the case demonstrates the ban was no impulsive act, but the product of extensive study by academics, parliamentary committees and government agencies alike. He expressed the hope that the law would be strengthened — in particular by expressly recognising the right to live in a sound environment, which the Constitution does not presently guarantee.

For her part, Ms Prokchon concluded that the task ahead is to ensure the polluter pays principle is set out clearly in the legislation, without loopholes, so that the burden no longer falls on state agencies or on the taxpayer.

Case details at a glance

Sources for this article — the panel discussion “Six Years of the Paraquat and Chlorpyrifos Ban: What Have Thais Gained, and What Have They Lost?”, broadcast live on 31 July 2026
· Kwanchai Muenying — BioThai Foundation, moderator
· Prokchon Usap — Coordinator, Thailand Pesticide Alert Network (Thai-PAN)
· Amarin Saichan — Lawyer, EnLAW Foundation
· Nattawadee Tengphanitkul — Legal Department, Foundation for Consumers

Primary sources — Judgments of the Central Administrative Court, Red Case No. Sor. 8/2569 and Red Case No. Sor. 7/2569, both dated 31 July 2026.