Mark Martinez planned to retire as president of Mission Support and Test Services, the Honeywell [HON]-led prime contractor for the Nevada National Security Site, according to people familiar with Martinez’s plans.

A spokesperson for Mission Support and Test Services (MSTS) did not reply to a request for comment.

Martinez has been president of MSTS since the contractor took over the site in 2017 under a site management and operations deal that, with options, is worth up to $5 billion through Nov. 30, 2027.

In that time, Martinez presided over the start of construction of one of the largest projects at the site since full-yield testing ceased in 1992: expansion of the U1a underground area into a modern, subcritical experiment facility that will verify the destructive power of the U.S. nuclear arsenal for much of the rest of this century.

In addition to hosting much of the National Nuclear Security Administration’s subcritical experiment facilities, the Nevada National Security Site supports an environmental mission run by the Department of Energy’s Office of Environmental Management, which is cleaning up after years of underground Cold War testing.