After eight years, the Supreme Court of Mendoza confirmed the constitutionality of the challenged Provincial Act No. 7,722 which prohibits the use of certain chemicals such as cyanide, mercury, sulfuric acid and other substances that are similarly toxic in the mining processes of exploration, exploitation and/or industrialization. This decision may be appealed to the Argentine Supreme Court.

The dispute dates back to 2007 when, following the issuance of the Provincial Act, several mining companies with interests in Mendoza began to bring individual claims in a dispute aimed at having the Act deemed unconstitutional.

In so deciding, the tribunal unanimously considered that the Act was issued within the regulatory powers of the Province of Mendoza, following the standard of reasonableness and as a complementary framework to the Federal Environmental Act.

It considered that the prohibition regarding the use of certain substances does not directly imply a general prohibition to perform mining activities, but rather it enhances the development of the mining industry in a context of the protection of the environment for present and future generations.

Among the main reasoning to declare the constitutionality, the Court stated:

• The provinces have the power to legislate on environmental protection by raising protection standards established by national standards and that the reasons of opportunity, merit or convenience taken into account by other branches of government are not subject to review and revocation through the constitutional control of legislation unless the conflict with the constitutional order ostensibly appears to noticeably affect the constitutional order or fundamental rights. Law 7,722, was the result of a vote on a consensus of all political sectors represented in the provincial legislature

• Every society defines and manages the model that it considers most suitable for its productive development, and its advantages and disadvantages in terms of growth and environmental impact it implies. Consequently, this determination is a political issue that cannot be reduced to a purely legal analysis. Rather this is a public policy determination which seeks to break down the polarization between competing sectors which cannot be exclusively addressed from a legal perspective.

• The implementation of the prevention and precautionary principle aims to foster and strengthen intergenerational responsibility and the duty of sustainability, i.e. to achieve a balance between environmental protection, economic progress and social development, without compromising the development of future generations.

• The court found that the right to a healthy environment was a human right and that it was within the court’s jurisdiction to ensure the right to protect the environment, achieve the use of renewable natural resources for sustainable development and the prevention of damage to the environment minimizing the impact of human activities.