In a joint report with advocacy group Pure Health published earlier this week, it said one in three children in the world aged up to 19, or around 800 million in all, suffer from lead poisoning, with blood lead levels (BLL) at or above 5 micrograms per deciliter (µg/dL), which can cause irreparable harm to the brain.

Vietnam has more than 3.24 million children with BLL more than 5 μg/dL, with 22,775 having a level of over 10 μg/dL.

In Southeast Asia, it has fewer cases than Myanmar (over 4.69 million), Indonesia (over 8.27 million) and the Philippines (over 20 million).

In East Asia and the Pacific, there are 77.67 million children with BLL of more than 5 μg/dL.

According to the report, children living in poor nations are exposed to lead, a potent neurotoxin, when inhaling dust and fumes from mines, smelters and recycling operations of lead-acid batteries (ULABs) which can be found in cars, trucks and other vehicles.

They can also get contaminated by other means such as eating food contaminated by lead-glazed pottery and lead-infused spices (turmeric and other), living in homes with peeling lead paint and being near lead-laced electronic waste dumps.

Other common sources of exposure mentioned in the report are lead in water from the use of leaded pipes, lead-based paint and pigments, leaded gasoline, lead solder in food cans, and lead in cosmetics, traditional medicines, toys, and other consumer products.

China has over 31.23 million kids with lead poisoning while India, the second most populous country, has over 275.56 million.

The metal can cause serious damage to children's brains, especially if they are under five years old, and lifelong neurological, cognitive and physical impairment.

Lead exposure also increases the risk of kidney damage and cardiovascular diseases in later life.

The report said there are over 900,000 premature deaths each year attributed to lead exposure.