The Minamata Convention, a United Nations pact launched Thursday, is designed to limit mercury use and emissions internationally. Finalized after four years of negotiations and signed by delegates of about 140 nations, the treaty includes many exemptions. (See below for news about the U.S. delegation.)

Here is what the treaty does – and doesn’t do.

1. Coal-fired plants, boilers and smelters
Nations must require best available emission-control technologies on new power plants, boilers and smelters, but they do not have to require them on older plants. Instead, they can take other steps for existing plants, such as emissions targets.

2. Light bulbs
Compact fluorescent bulbs of 30 watts or less will be banned by 2020 if they exceed 5 milligrams of mercury. Certain other halophosphate and fluorescent lamps also will be banned by 2020.

3. Mercury mining
Primary mining for mercury will be banned. Mercury mines already in operation can continue for 15 years and then will be banned.

4. Gold mining
Mercury will be allowed in artisanal and small-scale gold mining, where it is used to separate gold from rocks and sediment. The treaty encourages nations to reduce or phase out its use, but no targets or dates are included. Recent studies have documented that people in communities near artisanal mining areas in Peru and Brazil are highly exposed to mercury.

5. Dental fillings
Dental fillings are exempt from the 2020 ban. Countries agree to a phasedown of mercury in fillings by promoting alternatives, creating dental programs to minimize the need for fillings or taking other steps.

6. Vaccines
Vaccines that use mercury compounds (thimerosal) as a preservative are exempt.

7. Batteries
Mercury-containing batteries will be banned by 2020. An exception is button-cell batteries used in implantable medical devices.

8. Switches and relays
Switches and relays containing mercury will be banned by 2020.

9. Soaps and cosmetics
Soaps and cosmetics containing more than 1 part per million of mercury will be banned by 2020. Mascara and other eye-area cosmetics are exempt because of concerns that there are no safe substitutes.

10. Medical devices
Certain medical and monitoring devices – including barometers, thermometers, hygrometers, manometers and blood pressure monitors – will be banned by 2020.

11. Religious, traditional activities
Mercury used in religious or traditional ceremonies are exempt from the treaty.

12. Manufacturing
Mercury will be banned from chlor-alkali production and acetaldehyde production in 2025 and 2018, respectively. Manufacturing of polyurethane, vinyl chloride monomer and sodium or potassium methylate or ethylate are exempt although emissions must be reduced.

The Minamata Convention will go into effect 90 days after it has been ratified by at least 50 nations, which is expected to take several years. To ratify it, the nations first must enact their own domestic laws.

Editor's Note:

The United States sent a small delegation to Japan for the UN meeting to launch the treaty. But all of them left before signing it, reportedly because of the government shutdown.

“The U.S. delegation was recalled on Tuesday and returned to the U.S., apparently due to the government shutdown. No one from the U.S. is here and no one from the U.S. government will walk to the front of the room and sign the treaty in front of the global community,” said Joseph DiGangi, senior science and technical advisor at IPEN, an international consortium of environmental groups involved in the treaty negotiations.

Thursday’s event was mostly ceremonial; each nation has a year to sign the pact.

This article originally ran at Environmental Health News, a news source published by Environmental Health Sciences, a nonprofit media company.