An analysis of satellite images has revealed that small oil spills that have become common in the Gulf of Mexico are often much larger than reported, U.S. scientists say. Using technology that calculates the size of oil slicks based on differences in the texture of water surface, as captured in publicly available satellite photos, a team of oceanographers at Florida State University (FSU) estimated that known human-caused spills in the Gulf were typically about 13 times larger than reported to the U.S. Coast Guard’s National Response Center. The spills are typically the result of minor drilling mishaps or fuel discharges from ships. “There is very consistent underreporting of the magnitude of [oil] releases,” Ian MacDonald, a FSU scientist and team leader, told Nature. While these relatively minor oil spills may not cause significant environmental damage, the cumulative damage is not known since officials are unaware of the true extent of the spills, said John Amos, president of SkyTruth, a nonprofit organization that participated in the study.