Four Nigerian villagers and an environmental group are demanding oil company Shell take responsibility for damage from oil leaks caused by its Nigerian subsidiary, lawyers said Wednesday. The letters...accuse the company of...improperly maintaining equipment and failing to clean up spills that devastated crops and fish farms in the Niger Delta... A Shell spokesman in Rotterdam, Andre Romeyn, said he had not yet seen the letters. Shell would need to study them before deciding whether to publicly respond, he said... The government-owned Nigerian National Petroleum Corp. owns 55 percent [of Shell Nigeria], Royal Dutch Shell has a 30 percent stake,...Total SA owns 10 percent, and Italy's Agip [part of Eni] owns 5 percent... In its annual sustainability report, due to be released this week, The Anglo-Dutch company said that last year it completed the cleanup of 61 oil spills out of 74 sites. Of the remaining 13, its workers had been blocked from eight by the communities, according to the report...