Japan completed a procedure with the United Nations last month to ratify the Minamata Convention on Mercury. The convention is named after the city in Kumamoto Prefecture where industrial wastewater containing methyl mercury released by Chisso Corp.'s chemical factory into the sea caused birth defects and neurological diseases — known as Minamata disease — among thousands of people. Having experienced the dreadful results of mercury poisoning, Japan has a responsibility to help other countries in their efforts to prevent environmental pollution caused by mercury and mercury compounds. This is the aim of the convention.

Countries taking part in a U.N.-led conference held in the city of Kumamoto in 2013 adopted the convention, which describes mercury as a "chemical of global concern." So far 128 countries have signed the convention and 24 of them have ratified it. Japan is the 23rd country to ratify the convention, which needs to be ratified by at least 50 countries to take effect.

The convention prohibits the export and import of mercury except for certain kinds of use. Signatory countries must stop the production, export and import of products containing mercury such as thermometers, batteries and fluorescent lights by 2020 in principle. They also have a duty to reduce the release of mercury into the environment and to properly store and dispose of it. Japan needs to faithfully carry out the promise it made at the Kumamoto conference — to provide funds to developing countries and assist their governments in human resources development in their endeavor to minimize damage caused by mercury pollution.