A proposed expansion of a nuclear weapons parts manufacturer in south Kansas City could get a boost from a tax break Missouri lawmakers passed Friday.

With only hours left in Missouri’s annual legislative session, the state House voted 141-2 to authorize a sales tax exemption for construction materials purchased to expand the National Nuclear Safety Administration campus, operated by Honeywell International Inc. 

The legislation now goes to Gov. Mike Parson. 

State Rep. Chris Brown, a Republican from Kansas City, called the legislation a “win-win.” 

“It’s a small ask on the sales tax exemption,” he said, “and it’s really about economic development. And at the end of the day…it’s about making sure we are keeping our nuclear facilities, our nuclear defenses — keeping them safe, keeping them dependable, and keeping them reliable.”

The National Nuclear Security Administration plans to spend more than $3 billion to expand its facilities in Kansas City, where workers produce non-nuclear components of nuclear weapons, according to a fiscal analysis on the bill.

If the administration built the facilities itself, it would be exempt from sales tax as a government entity. But to expedite the expansion, the federal government plans to acquire the buildings from a private developer. Supporters of the legislation argue exempting the private developer will keep the costs on par with what the federal government would pay itself.

The fiscal analysis of the bill says it would divert about a combined more than $150 million in state, county, city and Kansas City zoo sales tax revenue over 10 years, but it says the exact cost couldn’t be verified.

Staff legislative staff wrote that the bill’s “fiscal impact could be significant.” 

Supporters of the legislation — including its sponsor in the Missouri Senate, now-former Sen. Greg Razer — argue the jobs created by the expansion would offset the losses from the sales tax exemption.

Razer told a Missouri Senate committee earlier this year that the National Nuclear Security Administration, part of the U.S. Department of Energy, plans to add 2.5 million square feet of facilities and hire thousands of employees to help modernize the nation’s nuclear weapons stockpile. 

“We need to modernize this to keep them safe to ensure that accidents don’t happen,” Razer said, “and that’s what we will be doing in Kansas City.”