Peat buildup is possible because water prevents oxygen from quickly decomposing plant matter.

He temporarily stopped breathing, which prevented oxygen from reaching his brain.

This fluid prevents enough oxygen from passing into the bloodstream.

Aluminum, on the other hand forms a non-porous oxide film that prevents oxygen from penetrating to the base metal.

Stroke, which can result from a progressive narrowing of blood vessels, preventing oxygen from reaching the brain.

It prevents daylight and oxygen from getting through.

This layer protects the metal by preventing oxygen from reaching it.

Some fire extinguishers work by preventing oxygen from reaching the burning materials.

Laura was born with a rare heart defect which prevented enough oxygen getting into her blood.

The brain might also begin to swell as a response to a stroke, where a blood clot prevents oxygen from reaching the brain.