The U.S. Army Corps of Engineers, St. Louis District, will host an open house to share information about clean-up activities impacting the Downtown and North St. Louis areas affected by low-level radiological contamination. The public is invited Thursday, Feb. 28, from 6 to 8 p.m., at Hazelwood Civic Center East, 8969 Dunn Road, Hazelwood, MO 63042.