In the seven months before the explosion and fire that injured 15 people and left an environmental mess, Jeff Boeyink -- a partner at Des Moines-based public relations and lobbying firm LS2group and Branstad’s chief of staff from 2010 to 2013 -- wrote to DNR leaders and Marengo officials at least 10 times on behalf of C6-Zero to answer questions, allay concerns and invite officials to tour the site, according to emails obtained by The Gazette.