What should a diver do if an oxygen analyzer reads above the expected Nitrox mix?

When an oxygen analyzer indicates an oxygen level that is higher than expected for a Nitrox mix, it is crucial to prioritize safety. This reading suggests that the gas mixture in the cylinder may not match the planned and certified blend for the dive. Diving with an incorrect mix can lead to serious safety issues, including oxygen toxicity, especially at greater depths where partial pressure of oxygen can significantly increase.

Not proceeding with the dive until the cylinder has been verified ensures that divers are using only gas that is within safe limits for their planned depth and time. Verification can include checking the cylinder’s markings, obtaining a new sample for analysis, or another means of confirming the gas mixture. This step is essential to maintain safe diving practices and prevent dive-related injuries or accidents.

While diving cautiously or adjusting the mix might seem like viable options, these do not address the fundamental safety issue posed by an incorrect blend. Therefore, avoiding the dive entirely until a safe and accurate mix is confirmed is the most responsible choice.