What is the primary cause of decompression illness?

The primary cause of decompression illness is related to not following the decompression tables. When a diver ascends too quickly after spending time at depths where the surrounding pressure is significantly higher than at the surface, nitrogen dissolved in the body can come out of solution too rapidly. This can lead to the formation of nitrogen bubbles in the bloodstream and tissues, which is what causes decompression illness, often referred to as "the bends."

Decompression tables provide critical information on how long a diver can safely remain at certain depths and how to ascend properly to avoid these risks. Following these guidelines allows the body to off-gas nitrogen at a safe rate, minimizing the likelihood of illness.

While diving with inexperienced buddies, using faulty equipment, and being exposed to strong currents can contribute to unsafe diving conditions, they do not directly cause decompression illness in the same way that improper ascent and failure to adhere to decompression protocols do.