Sickle Cell Trait and Scuba Diving-Reply

In Reply.—  In his letter, Dr Adams, referring to my letter to the editor, states: "The proposed ban on scuba divers with sickle cell trait is certainly not trivial." However, I suggested no ban (notoriously not enforceable) and only recommended that only those comparatively few carriers of the sickle cell trait with relatively high hemoglobin S concentrations of 35% to 45% —not all 8% of such carriers—avoid potentially hypoxic situations.Among potentially hypoxia-producing situations, diving was mentioned, which would include skin diving (snorkeling) as well as deep-water diving with self-contained underwater breathing apparatus (scuba). While the latter, as Dr Adams correctly points out, occurs under hyper- baric rather than hypobaric conditions, a notable increase has been observed in scuba diving-related accidents—owing to its increased popularity—and related by hypoxia, not hyperbarism. Ninety percent of fatal underwater accidents observed in ten years in Los Angeles County