Which law codified NASA's quarantine protocol for Apollo 11?

The Extra-Terrestrial Exposure Law codified NASA’s quarantine authority for Apollo 11.

Formally associated with 14 CFR Part 1211, the regulation gave NASA authority to protect Earth from possible harmful contamination brought back by astronauts, spacecraft, equipment, or lunar material. It was adopted in 1969, before Apollo 11’s historic landing.

The rule reflected a remote but serious scientific concern: unknown lunar organisms, if they existed, might be carried back to Earth. After returning, Armstrong, Aldrin, and Collins were isolated with lunar samples and equipment in the Lunar Receiving Laboratory at Houston. The Apollo 11 crew spent 21 days in quarantine after leaving the Moon.

The law was not the Outer Space Treaty, which governs international space activity, nor the National Aeronautics and Space Act, which established NASA. The Lunar Sample Protection Act is also a different concept. NASA later stopped enforcing the quarantine rules after lunar missions showed no biological hazard; the regulation was formally removed from the Code of Federal Regulations in 1991.