An attorney representing residents in San Francisco's Bayview Hunters Point neighborhood filed a class action lawsuit...against a firm contracted by the U.S. Navy to rid the area's former naval shipyard of radiation.  The lawsuit against Tetra Tech Inc., filed in San Francisco Superior Court by attorney Charles Bonner, is seeking $27 billion in damages, according to court documents.  The suit accuses Tetra Tech of "blatant, conscious, callous disregard of Bayview Hunters Point residents live, born and unborn" and "unfair and fraudulent business practices."  The suit seeks to represent all of the neighborhood's 38,484 residents...Pasadena-based Tetra Tech first began cleaning up radiation at the former Hunters Point Naval Shipyard in 2002 as the area was slated for redevelopment.  The Navy paid Tetra Tech $1 billion for the job...In December 2017, the U.S. Environmental Protection Agency...independently reviewed the Navy's report and found further signs of potential falsification, manipulation and data quality concerns at the parcels...[I]n an attempt to prove that it's cleanup data was not falsified, Tetra Tech offered to pay for an independent third party contractor to retest the site...The radiation contamination stemmed from the use of the yard to clean ships exposed to atom bombs and for research on defense against nuclear weapons.  Other contaminants from shipyard operations included petroleum compounds, mercury and lead.  The area, closed as a Navy shipyard in 1974, was designated in 1989 as an EPA Superfund site, having priority as one of the most toxic cleanup sites in the nation...