Well, here is part of an article published recently (2004) at the Journal of the Wilderness Medical Society:
"Very little is known regarding the behavioral pattern of adult moray eels, but smaller eels will avoid confrontation and retreat when approached. When they do attack, the wound is inflicted by fanglike teeth and vicelike jaws that lock. It is sometimes necessary to kill an eel or disarticulate its jaws to release its grip. The roof of a green moray eel's mouth is equipped with a third row of teeth, which help grasp prey. We do not know of any fatalities to have been reported. Most injuries tend to occur when divers insert their hands into holes occupied by eels or when the eels are attracted by freshly cut fish that the divers carry into the water. Consequently, hands tend to be the region most commonly bitten. A growing trend of sport divers engaging in hand feeding will undoubtedly lead to an increased number of incidents.
Although little evidence implicates moray eels as indiscriminate predators, an increased awareness among both emergency-treating personnel and ocean users of the potential severity of moray eel bites should minimize the risk of encounters. Recreational divers entering waters populated by moray eels should be cautioned to avoid direct contact. Since the attack on this diver, two subsequent scuba divers from the same region have sustained hand injuries from moray eels. Because little is known to explain why moray eels occasionally bite divers, the accumulation of information from these encounters should continue. This knowledge will enable us to better understand the motivations of these creatures and subsequently minimize the threat of dangerous encounters."
The full article is here where they describe a case of an attack in Cuba:
http://www.wemjournal.org/wmsonline/?reque...3&page=0194
Luiz