The Ghorusda Disaster was an incident that took place in the 24th century between the Federation (represented by Captain Darson of the USS Adelphi) and the Ghorusdans. On a first contact mission with Ghorusda, a misunderstanding between the crew of the Adelphi and the Ghorusdans resulted in the deaths of 47 crewpeople, including Captain Darson. First contact specialist Tam Elbrun was blamed by many (including Commander William T. Riker, who lost two friends and classmates from Starfleet Academy) for the incident for failing to advise Darson of Ghorusdan customs. A board of inquiry convened regarding the incident also cited his lack of awareness and competence about the situation. Elbrun claimed, however, that it was the incompetence of the Adelphi crew that resulted in the deaths. He also speculated that he might have become too enmeshed in the Ghorusdan culture and mindset, and failed to warn Darson as forcefully as he could have. The misunderstanding was of the nature of a cultural misinterpretation. (TNG: "Tin Man")
The exact cause of the disaster was never made clear in the episode, whether it was the actions (or inactions) of Elbrun or Darson that resulted in the deaths.