In the minutes after a cascade of gas explosions crippled the Deepwater Horizon on April 20, confusion reigned on the drilling platform. Flames were spreading rapidly, power was out, and terrified workers were leaping into the dark, oil-coated sea. Capt. Curt Kuchta, the vessel's commander, huddled on the bridge with about 10 other managers and crew members.

Andrea Fleytas, a 23-year-old worker who helped operate the rig's sophisticated navigation machinery, suddenly noticed a glaring oversight: No one had issued a distress signal to the outside world, she recalls in an interview. Ms. Fleytas grabbed the radio and began calling over a signal monitored by the Coast Guard and other vessels.

'Mayday, Mayday. This is Deepwater Horizon. We have an uncontrollable fire.'

When Capt. Kuchta realized what she had done, he reprimanded her, she says.

'I didn't give you authority to do that,' he said, according to Ms. Fleytas, who says she responded: 'I'm sorry.'

An examination by The Wall Street Journal of what happened aboard the Deepwater Horizon just before and after the explosions suggests the rig was unprepared for the kind of disaster that struck and was overwhelmed when it occurred. The events on the bridge raise questions about whether the rig's leaders were prepared for handling such a fast-moving emergency and for evacuating the rig -- and, more broadly, whether the U.S. has sufficient safety rules for such complex drilling operations in very deep water.

The chain of command broke down at times during the crisis, according to many crew members. They report that there was disarray on the bridge and pandemonium in the lifeboat area, where some people jumped overboard and others called for boats to be launched only partially filled.

The vessel's written safety procedures appear to have made it difficult to respondswiftly to a disaster that escalated at the speed of the events on April 20. For example, the guidelines require that a rig worker attempting to contain a gas emergency had to call two senior rig officials before deciding what to do. One of them was in the shower during the critical minutes, according to several crew members.

The written procedures required multiple people to jointly make decisions about how to respond to 'dangerous' levels of gas -- a term that wasn't precisely defined -- and some members of the crew were unclear about who had authority to initiate an emergency shutdown of the well.

This account of what happened aboard the rig at the time of the explosions, which killed 11, is based on interviews with survivors, their written accounts, testimony to the Coast Guard and internal documents of rig operator Transocean Ltd. and well owner BP PLC.

In written responses to the Journal, Transocean said that the time between the first sign of trouble and the catastrophic explosion was too short for the crew to have done anything to effectively prevent or minimize the disaster. The company also said the rig's chain of command was in place and 'did not hinderresponse time or activity.'

At a Coast Guard hearing on Thursday, Jimmy Wayne Harrell, the top Transocean executive on the rig, acknowledged under questioning that a split chain of command on the platform could lead to 'confusion' but it didn't hinderemergencyresponse. At the same hearing, Capt. Kuchta said that communications had not been a problem.

BP declined to comment on anything that happened April 20.

DOUGLAS A. BLACKMON / VANESSA O'CONNELL / ALEXANDRA BERZON / ANA CAMPOY

• horizon [hə´raizən] n.地平线；范围；视野 (初中英语单词)
• confusion [kən´fju:ʒən] n.混乱(状态)；骚乱 (初中英语单词)
• platform [´plætfɔ:m] n.(平)台；讲台；站台 (初中英语单词)
• commander [kə´mɑ:ndə] n.指挥员，司令员 (初中英语单词)
• worker [´wə:kə] n.工人；劳动者；工作者 (初中英语单词)
• operate [´ɔpəreit] v.(使)运转；操作；经营 (初中英语单词)
• distress [di´stres] n.痛苦 vt.使苦恼 (初中英语单词)
• interview [´intəvju:] n.&vt.接见；会见；交谈 (初中英语单词)
• examination [ig,zæmi´neiʃən] n.检查；考试；检验 (初中英语单词)
• journal [´dʒə:nəl] n.日记；日报；杂志 (初中英语单词)
• aboard [ə´bɔ:d] ad.&prep.在...上 (初中英语单词)
• disaster [di´zɑ:stə] n.灾难，不幸 (初中英语单词)
• complex [´kɔmpleks] a.复杂的 n.综合企业 (初中英语单词)
• respond [ri´spɔnd] v.回答；响应；有反应 (初中英语单词)
• swiftly [´swiftli] ad.迅速地，敏捷地 (初中英语单词)
• contain [kən´tein] v.包含；容纳；抑制 (初中英语单词)
• shower [´ʃauə] n.展出者；阵雨；淋浴 (初中英语单词)
• account [ə´kaunt] vi.说明 vt.认为 n.帐目 (初中英语单词)
• operator [´ɔpəreitə] n.操作者；接线员 (初中英语单词)
• executive [ig´zekjutiv] a.行政的 n.行政官 (初中英语单词)
• comment [´kɔment] n.&v.评论；评注；注意 (初中英语单词)
• navigation [,nævi´geiʃən] n.航行；航空；导航 (高中英语单词)
• emergency [i´mə:dʒənsi] n.事变；紧急关头 (高中英语单词)
• crisis [´kraisis] n.转折点；危机 (高中英语单词)
• senior [´si:niə] a.年长的 n.前辈 (高中英语单词)
• critical [´kritikəl] a.批评的；关键性的 (高中英语单词)
• precisely [pri´saisli] ad.精确地；刻板地 (高中英语单词)
• testimony [´testiməni] n.证明；证据；表明 (高中英语单词)
• internal [in´tə:nl] a.内部的；国内的 (高中英语单词)
• explosion [ik´spləuʒən] n.爆炸；爆发；发作 (高中英语单词)
• hinder [´hində, ´haində] vt.阻止 a.后面的 (高中英语单词)
• response [ri´spɔns] n.回答；响应 (高中英语单词)
• hearing [´hiəriŋ] n.听力；听证会；审讯 (高中英语单词)
• cascade [kæ´skeid] n.小瀑布；喷流 (英语四级单词)
• bridge [bridʒ] n.桥(梁)；鼻梁；桥牌 (英语四级单词)
• overboard [´əuvəbɔ:d] ad.向船外；到水中 (英语四级单词)
• partially [´pɑ:ʃəli] ad.部分地；局部地 (英语四级单词)
• calling [´kɔ:liŋ] n.点名；职业；欲望 (英语六级单词)
• broadly [´brɔ:dli] ad.广，宽；明白；粗鲁 (英语六级单词)
• initiate [i´niʃieit] vt.开始；引进；启蒙 (英语六级单词)
• effectively [i´fektivli] ad.有效地 (英语六级单词)
• minimize [´minimaiz] vt.将...减至最小量 (英语六级单词)