The U.S. Environmental Protection Agency said today it will require contractors who renovate or repair older housing, child-care facilities or schools to be trained to prevent lead contamination.

The rule will cover significant work done on buildings that were built before 1978 and are occupied by children or pregnant women. It is set to take effect in April 2010 to allow time to create training standards and programs.

Renovations can disturb old lead paint and create lead dust, which can be especially toxic to children. Such work accounts for about half of the 200 to 250 lead poisoning cases each year in Maine, although the vast majority of those cases are associated with do-it-yourself renovations.

The EPA’s training requirement applies only to professional contractors, although the federal and state government are increasing efforts to educate homeowners and others who do their own work. Maine officials, for example, plan to send lead-safe renovation advice to all families with young children this spring.

The training requirement will add about $35 to the cost of a renovation or repair job, according to EPA. It will strengthen protections for 1.4 million children, it said.