A chemical gas leak from a rail tanker near Cincinnati prompted fears of an explosion and evacuation orders for people within at least a half-mile radius of the incident. Roughly 210 households in Whitewater Township, about 22 miles west-northwest of Cincinnati in an area near the city airport and the Kentucky state line, were under evacuation orders, officials said Tuesday night. Other residents were under shelter-in-place recommendations, they said at a news conference.