After nearly four years of legal challenges and revisions, contractors and unions face stiffer federal safety mandates after April 22 for lead-paint dust containment in homes and public facilities built before 1978 that are occupied by children under the age of seven. The U.S. Environmental Protection Agency says its Renovation, Repair and Painting Rule will reduce child lead-poisoning levels, but some construction groups are concerned about added cost for small contractors as well as insufficient worker training around the U.S. Union painters practice new lead-paint-abatement protection techniques. The rule, first proposed in 2006, requires renovation workers to be EPA-certified and
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.