Funeral directors reacted angrily yesterday to a government plan to halve the amount of mercury emissions produced by the burning of amalgam teeth fillings, warning it could add up £100 to the cost of a cremation and was unjustifiable.

"No scientifically quantifiable study has been done and it will be the bereaved who will have to foot the bill," said Dominic Maguire, a spokesman for the National Association of Funeral Directors.

Under the scheme, to be presented today after five years of consultations, crematoriums must halve their mercury emissions by 2012.

According to the Department for Environment, Food and Rural Affairs, each dead body contains an average 2.1 grams of mercury from amalgam fillings.

Mercury emissions have been linked to birth defects, kidney disease and multiple sclerosis. Unless action was taken soon, crematoriums would become the single largest mercury polluters in the UK by 2020, Defra said.