5,000 Tonnes of Mercury in Teeth: The Hidden Environmental Time Bomb

For environmental regulators and climate advocates, the mercury stored in dental fillings represents a diffuse and persistent pollutant released through cremation, wastewater, and landfill. The WHO workshop signals a regional effort to close this pollution pathway, linking oral health policy directly to ecosystem protection and public health safety.

On July 13, 2026, the World Health Organization’s South-East Asia Regional Office convened a two-day workshop in Bangkok, bringing together health and environment policymakers to accelerate the phase-out of dental amalgam, a mercury-containing filling material. This gathering follows the landmark decision at the Sixth Conference of the Parties (COP6) to the Minamata Convention on Mercury in 2025, which shifted the global approach from merely 'phasing down' amalgam to a complete phase-out by 2034. The workshop signals an intensified regional commitment to translate that international legal obligation into national action plans across the 11 countries of WHO South-East Asia—a region home to over two billion people and a rapidly growing demand for dental services.

“

Dental amalgam, a durable and inexpensive material used in restorative dentistry for over 150 years, consists of approximately 50% elemental mercury mixed with a powdered alloy of silver, tin, and copper.

Dental amalgam, a durable and inexpensive material used in restorative dentistry for over 150 years, consists of approximately 50% elemental mercury mixed with a powdered alloy of silver, tin, and copper. Mercury, however, is classified by WHO as one of the top ten chemicals of major public health concern due to its neurotoxic and nephrotoxic effects, particularly to fetuses and young children. Throughout its lifecycle—from manufacture, chairside placement, and removal to waste disposal—amalgam releases mercury vapor and particulate into the environment, contaminating air, soil, and water. Ultimately, this mercury methylates in aquatic ecosystems and bioaccumulates in the food chain, especially in fish, posing long-term health risks to communities that rely on fish as a dietary staple. According to the United Nations Environment Programme (UNEP), between 3,000 and 5,000 metric tonnes of mercury are currently stored in the teeth of people worldwide, a slowly leaching reservoir that demands both environmentally sound management of existing fillings and a definitive stop to new placements.

The 2025 Minamata COP6 decision was a culmination of mounting scientific evidence and advocacy, expanding an earlier phase-down objective from the Convention’s 2019 amendment. The 2034 deadline gives countries a clear time-bound target, but also triggers immediate necessities: national regulations to prohibit amalgam use, procurement and subsidy shifts toward mercury-free alternatives, retraining of dental professionals, and establishment of protocols for safe amalgam removal and waste separation. The WHO workshop in Bangkok directly addressed these challenges, with Dr Catharina Boehme, Officer-in-Charge of the WHO Regional Office, highlighting the dual benefits of protecting population health while advancing 'prevention-oriented, minimally invasive and more sustainable oral health care.'

The transition to alternatives is central to the health argument. Mercury-free filling materials—such as resin composites, glass ionomer cements, and ceramics—not only avoid mercury exposure but often align with modern minimally invasive techniques that preserve more natural tooth structure. However, these alternatives currently come at a higher material cost and require different skill sets and equipment, raising questions of affordability and accessibility in low- and middle-income countries that dominate the South-East Asia region. The workshop explored strategies to expand access to safe, effective, and people-centred oral health services without perpetuating a two-tier system where only wealthier populations benefit from mercury-free dentistry. International financing, technology transfer, and local manufacturing of alternative materials were likely on the agenda, though details remain sparse from the initial statement.

From an environmental perspective, the phase-out addresses a significant but often overlooked source of global mercury emissions. Cremation, which is practiced widely in parts of South-East Asia, releases vaporized mercury from dental fillings directly into the atmosphere, contributing to global mercury cycling and deposition even far from the source. Dental clinics’ wastewater can carry amalgam particles into municipal sewage, eventually reaching water bodies. Effective implementation requires parallel investment in amalgam separators in dental chairs and centralized waste treatment facilities—areas where policy and infrastructure are currently inadequate in many regional countries. The workshop thus represents a 'whole-of-government' approach, linking health ministries with environmental protection agencies, an integrated effort that has been relatively rare.