What can be a consequence of failing to account for residual nitrogen time before a dive?

Failing to account for residual nitrogen time before a dive can lead to a potential risk of decompression sickness. When divers ascend to the surface after spending time at depth, nitrogen absorbed by their body tissues during the dive must be eliminated safely. If a diver doesn't adequately consider the time spent at depth and the accumulated nitrogen, they may ascend too quickly or make inadequate safety stops. This can lead to nitrogen bubbles forming in the bloodstream or tissues, resulting in decompression sickness, commonly known as "the bends."

The importance of understanding residual nitrogen time lies in planning subsequent dives and ensuring that the body has the necessary time to off-gas the nitrogen before engaging in further diving activities. Proper dive planning, which includes tracking residual nitrogen levels, is essential for minimizing this risk and ensuring safe diving practices.