Heavy rainfall in northern Vietnam has killed 17 people and inundated major coal mines, causing concern among environmentalists about contamination of local communities and the waters of a top tourist attraction, Ha Long Bay.
Six days of rain in Quang Ninh province have displaced thousands of people, with houses and roads deluged by floodwater that environmental groups said is filled with potentially hazardous coal dust.
Hal Long Bay, with its floating villages, vast caves and green-tinged limestone rocks, is a UNESCO World Heritage site visited by millions of tourists each year. Many take boat trips for several days and often swim in its waters.
The region is also a major source of coal, thousands of tonnes of which were swept away in the floods, according to the country's top mining firm, state-owned Vietnam National Coal and Mineral Industries Corporation (Vinacomin).
Damage so far was estimated at VND2 trillion (US$91.7 million), half of which affects Vinacomin, according to the government's news website, which made no reference to any pollution threat.
Vinacomin's chairman was quoted on the firm's website as saying operations at many of its coal mines had been suspended.
Heavy rain is likely to continue until Monday and spread to other northern provinces, according to the national weather centre.
Donna Lisenby of Waterkeeper Alliance, an international environmental group campaigning for clean water resources, said the damage to coal mines could contaminate water with hazardous substances like arsenic, lead and thallium.
"Coal waste facilities are ticking time bombs if they are not properly constructed to withstand large rainfall events," she said in a statement.
"There have not been sufficient efforts to protect surrounding communities."