back-contamination

This is often provided for intermittent overflows, or where an air gap is required, to avoid possible back-contamination.

Back-contamination - The theoretical contamination of Earth's biosphere from microbial extraterrestrial organisms.

Back-contamination is the informal but widely employed name for the hypothetical introduction of microbial extraterrestrial organisms into Earth's biosphere.

Just as the Wolf had access to her memories, so, by some faint and perhaps deliberate process of back-contamination, she sensed some of its own history.

The threat of back-contamination from the Moon was the main reason for quarantine procedures adopted for the Apollo program, up until the completion of Apollo 14.

Back-contamination - humans acquiring and spreading Martian viruses - is described as "just plain nuts", because there are no host organisms on Mars for disease organisms to have evolved.

We need, for example, a wide range of specialists to cope with potentially calamitous, though perhaps unlikely, contingencies: back-contamination of the earth from the planets or stars, the need to communicate with extra-terrestrial life, monstrosities produced by genetic experimentation, etc.

The Lunar Receiving Laboratory (LRL) was a facility at NASA's Lyndon B. Johnson Space Center (Building 37) that was constructed to quarantine astronauts and material brought back from the Moon during the Apollo program to mitigate the risk of back-contamination.