The U.S. Occupational Safety and Health Administration said on May 5 that it has proposed a $55,000 fine against Mollenberg-Betz Inc., a Buffalo, N.Y., mechanical contractor, for eight serious violations of workplace safety standards following a fatal explosion last November at a Tonawanda, N.Y., chemical plant. The blast killed Richard Folaron, a welder who worked for Mollenberg-Betz. OSHA also proposed a $61,000 fine against DuPont Corp., the plant's owner, for nine serious violations. It says Folaron was welding atop a 10,000-gallon slurry tank when sparks ignited vapors, causing the blast that killed him and injured another employee. OSHA cited Mollenberg-Betz
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.