The National Research Council has again called into question the wisdom of building a 500,000-square-foot research lab to test animal diseases in the heart of the United States. The latest NRC report—which evaluates a recent Department of Homeland Security risk assessment for the proposed lab in Manhattan, Kansas—found the new assessment an improvement in some ways, but didn’t buy low estimates of accidental pathogen release.

The most recent DHS assessment veered sharply from an earlier assessment which found a 70 percent chance that outside infection would occur over the 50-year lifespan of the planned National Bio- and Agro-Defense Facility (NBAF), according to a NRC news release. Instead, the new analysis estimates a less than one percent chance per year, and shifts the most likely cause of such a release from human error to natural disasters.

“The committee noted that some of the risk reduction may be explained by improvements to the latest design plans for the facility, but despite improvements, the updated assessment underestimates the risk of an accidental pathogen release and inadequately characterizes the uncertainties in those risks,” the news release stated. “Moreover, the committee found that the updated probabilities of releases are based on overly optimistic and unsupported estimates of human-error rates; low estimates of infectious material available for release; and inappropriate treatment of dependencies, uncertainties, and sensitivities in calculating release probabilities.”

The NBAF—which would research contagious animal diseases such as foot-and-mouth disease, African swine fever, and Japanese encephalitis—has been embattled since its inception. Early on, the Government Accountability Office had concerns about the disease research being moved to the U.S. mainland. (The NBAF would replace New York’s Plum Island center, located on a federally-owned island off the northern tip of Long Island).

In 2008 and 2009 reports, the GAO concluded that the DHS hadn’t provided sufficient evidence that foot-and-mouth disease research could be conducted safely on the mainland and hadn’t adequately estimated the impacts of an outbreak. In 2010, the NRC released a stern report that came to a similar conclusion.

The project has been highly sought after by state and local government officials for its economic benefits, despite public resistance. Even after another round of questionable assessments, Kansas and Missouri lawmakers are clamoring for the Obama administration to release funds so they can start building, according to the Kansas City Star.

“Delays to the timeline only result in increased costs for contracts, labor and materials,” the senators wrote, according to the Star. “More importantly, delays result in an increased risk on our nation’s security."