NASA will be conducting extensive reviews of workplace safety at two of its major commercial partners, SpaceX and Boeing, prompted by SpaceX CEO Elon Musk’s drug use. Both companies are currently developing spacecraft to take the NASA’s astronauts to and from the International Space Station.

The reviews are expected to take months and will require hundreds of interviews, according to The Washington Post, which first reported the news. It’s unclear if the inquiries will delay the first launches of the companies’ vehicles, which are supposed to take place next year.

NASA apparently decided to do the reviews after Musk smoked marijuana on Joe Rogan’s podcast in September, according to The Washington Post. The event stirred up controversy and numerous headlines at the time, even though the podcast was recorded in California, where recreational marijuana is legal. The problem is that while the recreational use of marijuana is legal in 10 states, including California, it’s still verboten federally. SpaceX is a pivotal launch provider for both NASA and the US military, and both of those government entities either prohibit or discourage recreational drug use.

“NASA will be conducting a cultural assessment study in coordination with our commercial partners to ensure the companies are meeting NASA’s requirements for workplace safety, including the adherence to a drug-free environment,” a NASA spokesperson said in a statement to The Verge. “We fully expect our commercial partners to meet all workplace safety requirements in the execution of our missions and the services they provide the American people. As always, NASA will ensure they do so.”

NASA’s administrator Jim Bridenstine says that the reviews will help NASA ensure that its astronauts will be as safe as possible. “If I see something that’s inappropriate, the key concern to me is what is the culture that led to that inappropriateness and is NASA involved in that,” Bridenstine told The Washington Post. “As an agency we’re not just leading ourselves, but our contractors as well. We need to show the American public that when we put an astronaut on a rocket, they’ll be safe.” Bridenstine also argued that a company’s “culture and leadership start at the top.”

Both SpaceX and Boeing are key contractors for NASA. Boeing was the primary manufacturer of the International Space Station, and the company is currently building NASA’s next deep-space rocket, the Space Launch System. Meanwhile, SpaceX is responsible for regularly launching cargo to the ISS, and the company was recently certified by NASA to launch the agency’s most expensive and most complex science missions. In 2014, NASA selected the two companies as finalists for the Commercial Crew Program, an initiative to launch NASA astronauts on private US vehicles. Since the end of the Space Shuttle program, NASA has had to rely on the Russian Soyuz rocket to get its astronauts to space — a deal that costs the space agency more than $80 million a seat.

As of this month, SpaceX has been planning to fly the first uncrewed test flight of its vehicle, the Crew Dragon, as early as January 2019. If successful, that flight would then be followed by a crewed test launch, currently slated for June 2019. As for Boeing, the company is targeting March 2019 for an uncrewed test flight of its vehicle, the CST-100 Starliner, and a crewed test flight in August 2019.

The Commercial Crew Program has suffered from numerous delays prior to today, as well as safety concerns from industry experts. Some have raised concerns about SpaceX’s plan to fuel its rockets with people on board — a procedure that experts considered unsafe. And recently, Boeing experienced a propellant leak during a test that pushed back development of its Starliner. Plus, multiple audits from the Government Accountability Office have called into question the target dates for the program, arguing that they’re too aggressive. Now it’s even more uncertain if the upcoming dates will hold. The Verge asked NASA if the reviews would delay the launch dates, but the agency declined to comment.

Both companies proclaim that safety is a number one priority for them. “Human spaceflight is the core mission of our company,” SpaceX said in a statement. “There is nothing more important to SpaceX than this endeavor, and we take seriously the responsibility that NASA has entrusted in us to safely and reliably carry American astronauts to and from the International Space Station.” The company also added: “SpaceX actively promotes workplace safety and we are confident that our comprehensive drug-free workforce and workplace programs exceed all applicable contractual requirements.”

Boeing, which promotes an alcohol and drug-free workplace, also offered a similar statement: “The culture at Boeing ensures the integrity, safety and quality of our products, our people and their work environment,” Boeing said. “As NASA’s trusted partner since the beginning of human spaceflight, we share the same values and are committed to continuing our legacy of trust, openness and mission success.”