Preliminary findings from a federal investigation into potential health problems from drywall imported from China are inconclusive, the U.S. Consumer Product Safety Commission said on Oct. 29. CPSC has received nearly 1,900 complaints from residents in 30 states about effects of Chinese-made wallboard. CPSC says preliminary tests found Chinese drywall has elemental sulfur and higher strontium concentrations than other types of drywall. But it says more studies are needed to show a link between the drywall and reported health problems. In the meantime, the commission is working with the Dept. of Homeland Security to identify and stop imports of drywall
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.