Beneath the Carbon Sea by Hyeok Lim

Kestrel Habitat was built to survive the pressure of the North Sea. It was not built to survive a ruptured carbon-storage well.

Saturation diver Nessa Rourke has six hours to reach C-14 and close the breach before seafloor scour tears Kestrel apart. But the blowout has carried something into the habitat: a pressure-adapted organism that wakes at the gas–liquid boundary inside a human lung. The crew can still breathe. They can still move. That is what makes it dangerous.

As clean spaces shrink and the rescue system becomes a possible vector, Nessa must choose between the fastest way out and the one plan that might keep the contamination below. The escape route and the containment plan cannot both survive.

Beneath the Carbon Sea is a claustrophobic survival-horror thriller about competence under pressure, contaminated rescue, and the cost of keeping a disaster contained.