Decompression (diving) but in later experiments signs of what was later to become known as decompression sickness were observed. Later, when technological advances allowed the use of pressurization of mines and caissons to exclude water ingress, miners were observed to present symptoms of what would become known as caisson disease, compressed air illness, the bends, and decompression sickness. Once it was recognized that the symptoms were caused by gas bubbles, and that re-compression could relieve the symptoms, Paul Bert showed in 1878 that decompression sickness is caused by nitrogen bubbles released from tissues and blood during or after decompression, and showed the
CMAS* SCUBA Diver CMAS* SCUBA Diver CMAS * SCUBA Diver, CMAS one-star Scuba diver, or just CMAS * is an entry level diving certification for recreational SCUBA issued by Confédération Mondiale des Activités Subaquatiques (CMAS), enabling divers to undertake accompanied no-decompression dives to a maximum depth of twenty meters. CMAS describes that a One Star Diver shall be deemed "to have sufficient knowledge, skill and experience to procure air, equipment, and other diving services and to plan, conduct, and log open-water dives that do not require mandatory in-water decompression stops, without the supervision of a CMAS Instructor or CMAS Dive Leader, when properly