Last Tuesday marked the 20th anniversary of the countryâÄôs largest oil spill. Yet Exxon Mobil Corp., despite its close association with the poster child of environmental disasters, has not learned from its mistakes. I cannot speak to whether ExxonMobil still hires drunks to captain its supertankers, but the company has balked at a simple precaution to reduce the likelihood of another oil catastrophe. In 1989, 100 percent of the oil supertanker fleet was single-hulled, including the Exxon Valdez. Since then, the percentage has dropped to just 21 percent as that old design is phased out in favor of much safer double-hulled ships. And that percentage will continue to decline. Single-hulled tankers will be banned from the United States in 2015, and a similar ban by the U.N. International Maritime Organization will go into effect next year. France and Spain havenâÄôt even allowed single-hulled tankers within 200 miles of their shores since their own major spills in 1999 and 2002, respectively. As a result, most Western oil companies have abandoned risky single-hulled tankers even ahead of the upcoming bans. But ExxonMobil has brazenly defied this logical trend. The nationâÄôs largest oil company remains the biggest Western user of single-hulled tankers. And this is not just a function of its size: In 2008, ExxonMobil hired more single-hulled tankers than the next nine largest companies combined. Why? The only apparent benefit is that the older, more accident-prone tankers cost about 20 percent less to rent. Bloomberg estimates that choosing single-hulled tankers saved ExxonMobil less than 1 cent per share in 2008. Granted, that scales to savings of about $18 million, but compared to the companyâÄôs record $45.2 billion in profit last year, that’s not even a drop in the barrel. And if you consider the $3.8 billion cost for Valdez cleanup and damages to date, any cost-benefit analysis becomes even more absurd. Such flagrant disregard for environmental safety reinforces the negative feelings many still harbor toward ExxonMobil. But they donâÄôt seem to care. The Exxon Valdez (repaired, renamed and sold) is banned from returning to the Prince William Sound. But ExxonMobil still operates the ValdezâÄôs single-hulled sister ship, the SeaRiver Long Beach, and regularly sails it right through the scene of the crime. All the Valdez experience has taught ExxonMobil is that the courts are their friends. In repeated legal battles after the spill, ExxonMobil was able to reduce its punitive fines by almost 90 percent and delay that restitution for literally decades. After its Supreme Court victory in 2008, ExxonMobil owed the equivalent of just four daysâÄô profit in damages. ThatâÄôs not a deterrent; itâÄôs barely a slap on the wrist. In 1989, ExxonMobilâÄôs CEO predicted that the Prince William Sound would be completely restored in just a few years. And earlier this month, the company claimed that the area has recovered with âÄúno long-term damage.âÄù This is patently untrue; oil can still found be on or under many of the soundâÄôs beaches. Although shipping spills have decreased with the post-Valdez regulatory improvements, its risks are intrinsic and will never be completely averted. And offshore drilling poses similar threats with a whole host of new ones. Oil spills will inevitably continue as long as we rely on this dirty, climate-altering fuel (as if we needed another reason to pursue alternative energy). Transition from oil is a long-term goal, but it won’t become reality without short-term action. In the meantime, we need to hold companies like ExxonMobil fully accountable for mistakes of such egregious magnitude. We cannot afford to let them repeat their history, even if they refuse to learn from it. This column, accessed via UWire, was originally published in The Duke Chronicle at Duke University. Please send comments to [email protected].