UPDATE 1-US to finalize stricter soot standards on Friday

WASHINGTON, Dec 14 (Reuters) - The Obama administration will finalize stronger limits on harmful soot pollution from power plants and diesel engines on Friday, two health groups said.

The new standards, which the Environmental Protection Agency was under court order to finalize, will limit annual average soot emissions to about 12 micrograms per cubic meter of air from the standard of 15 micrograms set in 1997, the groups said.

Individual states will be responsible for deciding how to limit the emissions of fine particulates, which can threaten the elderly, people with heart disease and children.

When the EPA proposed the rules in June it said only six counties in California, Arizona, Alabama, Michigan and Montana are out of compliance with the standard. It also said the reduction in health bills from the standard would far outweigh the costs to industry.