The U.S. Justice Dept. and consultant Tetra Tech are ramping up a battle over alleged false claims for payment the firm submitted to the U.S. Navy under $261 million in contracts for radiological tests and cleanup at San Francisco’s former Hunters Point base, a Superfund site being developed for up to 12,000 residential units.

In an April 29 response to a Tetra Tech motion to have a federal court dismiss the government’s breach-of-contract lawsuit, DOJ says the firm’s alleged conduct—that it knowingly prepared and submitted false test results—“strikes at the very heart of its bargain with the Navy.”

The government joined three existing whistleblower federal court cases and seeks treble damages.

In its motion to dismiss, Tetra Tech says the claims primarily come from falsified soil samples in 2012 by two ex-employees who pleaded guilty, which it investigated and addressed in coordination with the Navy.

Tetra Tech says DOJ’s false claims allegations could be the result of “political pressure and negative press” about the cleanup of the 500-acre Hunters Point site. They are based solely on facts known to the Navy since 2012 and “rank speculation unsupported by any facts,” the firm says.

Last month, the Federal Employees for Environmental Responsibility filed a Freedom of Information suit to force the Navy to release records of its plan to remedy false soil sampling and building survey data.

Local advocates want an extensive independent site retesting, including areas where new homes have been built.

Tetra Tech also told media last month that it proposed to the Navy to pay for an independent review of its work and that the Navy had not responded as of April 25.

The Navy said in March that Tetra Tech’s more limited environmental work on the Treasure Island former military site in San Francisco Bay, also set to be redeveloped, was “determined to be consistent and accurate,” with no site health risks, said a local media report.