Some divers use nitrox, which usually has a higher percentage of oxygen than air, often 32% or 36% in EAN32 and EAN36, respectively. This lets them stay underwater longer for the same decompression requirement as for air, because less nitrogen is absorbed into the body's tissues. The drawback to the higher oxygen content is that at higher than normal partial pressures, oxygen becomes toxic, so scuba divers generally limit their exposure to oxygen partial pressures of less than 1.6 bar,[37] by limiting the maximum operating depth for the mixture.