The city of Grass Valley has identified four areas within its jurisdiction where redevelopment would help the vitality of the municipality, but toxic substance issues continue to dog efforts to launch the improvement projects. In 2009, the U.S. Environmental Protection Agency provided the city of Grass Valley with $400,000 in grant money to make an inventory of the properties in four areas identified as eligible of significant redevelopment. The city then hired Converse Consultants, which presented their findings at a public meeting Thursday in Grass Valley to a modest gathering of interested parties including property owners, said Izzy Martin, CEO …