KANSAS CITY, Mo. (AP) - Even before the deadly tornado struck Joplin, Mo., federal officials say they planned to modify the design of the new Kansas biosecurity lab to better withstand tornadoes and strong winds.

The Department of Homeland Security is building a $650 million National Bio and Agro-Defense Facility near Kansas State University in Manhattan. A spokesman told the Kansas City Star that the lab would be constructed to withstand 230 mph winds, a standard used for the nation's nuclear power plants.

DHS spokesman Chris Ortman said the new design standard exceeds those for a federally approved tornado shelter and that "the updated design is now undergoing a third-party review by a risk assessment team" as a further guarantee of its safety.

Critics have warned that a tornado could cause significant damage to the lab and an accidental release of deadly pathogens. Manhattan was hit by a tornado in 2008, though it was weaker than the Jopl in storm, which had winds estimated to exceed 200 mph.

"I'm not a meteorologist or an engineer, but I don't think DHS has established that it would be safe," said Tom Manney, a retired Kansas State University professor involved with a group called No NBAF in Kansas.

The new lab is scheduled to be operational by 2018 and replace an aging laboratory at Plum Island, N.Y. The lab will conduct research on deadly plant and animal pathogens, including foot-and-mouth disease.

A government study released last year concluded that a release of foot-and-mouth pathogens from the Kansas lab could cost the cattle industry more than $5 billion.

Bill Bullard, director of a cattle producers' lobbying group called R-CALF, also said that "the U.S. government has simply ignored the vagaries of weather which could well cause an inadvertent release of some very dangerous viruses."

Supporters said the design upgrades, including using reinforced concrete, tornado dampers and other devices, should adequately protect the public and livestock from an accidental pathogen release in the event of a tornado strike.

"The research work will be done in a containment facility that amounts to a shell within a shell within a shell," said Sherriene Jones-Sontag, a spokeswoman for Kansas Gov. Sam Brownback.

In a 2010 risk analysis of the new lab, scientists said the chance of a tornado striking the lab was remote, pegging the likelihood of a small tornado with 150 mph winds causing a pathogen release at once every 770 years. However, the analysis recommended design changes to guard against stronger storms.

The Kansas City Star obtained DHS records that showed the agency agreed in February to strengthen the lab's design. The agency didn't release how much the changes would increase the lab's construction costs, but the earlier risk analysis estimated that strengthening the lab to withstand an EF-2 tornado - which would have winds of 113 mp h to 157 mph -.could top $60 million.

Construction on the lab is scheduled to begin next year, with site and design work under way.

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Information from: The Kansas City Star, http://www.kcstar.com

Copyright 2011 The Associated Press.