Oil spills don’t make the news very often unless they are big, like the 2010 Deepwater Horizon spill, which killed 11 people and spewed an estimated 205 million gallons of oil into the Gulf of Mexico. But spills happen frequently. According to data from the U.S. National Oceanic and Atmospheric Administration (NOAA), there were 137 oil spills in 2018, about 11 per month.
NOAA updates their incident reports of oil and chemical spills every day through their Emergency Response Division. You can see where the reported spills occurred in the map below from Resource Watch.
The 148 incidents in the map includes incidents of spills and potential spills. From the descriptions of the spills, nine of the incidents didn’t actually detect any pollution (NOAA gets notified when there is a possible spill, when an oil-carrying boat breaks down, for example, but some incidents don’t result in spills) and two occurred outside U.S. territories. So the total number of U.S. oil spills in 2018 was 137.
Spills can happen onshore and offshore. NOAA tracks spills as they are reported, from direct observations (oil spilling from a container, a large fire at a refinery, etc.) or indirect observations (an oil sheen, a sinking boat containing oil, etc).
NOAA estimated the size of 65 spills in 2018, in terms of the maximum potential gallons of petroleum released. Spills ranged in size from 2.1 million gallons to just 30 gallons. NOAA can’t estimate the size of a spill if its source is unknown, such as in the case of oil sheens like the one shown below.
The International Tanker Owners Pollution Federation (ITOPF) defines a large oil spill as more than 700 tonnes (219,000 gallons) of oil and a medium-sized spill as being between 7 and 700 tonnes (2,200 gallons to 219,000 gallons). Of the 137 oil spills tracked by NOAA, one was large and 25 were medium-sized.
Louisiana had 52 spills on or offshore, Texas had 13 and 10 spills occurred in Alaska. New Jersey and Massachusetts are tied for fourth place with six spills within 200 nautical miles of their shores.
The largest spill of the year involved an explosion at a refinery in Superior, Wisconsin on April 26. At least 11 people were injured. The explosion caused storage tanks of asphalt to leak and catch fire. NOAA estimates the maximum potential release to be more than 2.1 million gallons, enough to fill 35,000 bathtubs.
On December 1, 2018, the U.S. Coast Guard reported the release of synthetic oil-based mud to the sea floor. An offshore drill rig had to make an emergency disconnect from the well head on the sea floor because of high winds and rough seas. NOAA estimates the maximum potential release at 84,000 gallons.
About 1,000 barrels of oily water was discharged into the Theodore Ship Canal on February 12, just south of Mobile, Alabama. NOAA estimates as much as 42,000 gallons were involved. Cleanup methods included skimming oil off the water and cleaning it off the shoreline.
There were two oil spills near the U.S. territory of American Samoa in 2018. One occurred on December 5, 2018, when a 228-foot commercial fishing boat carrying as much as 90,000 gallons of diesel fuel and 300 gallons of gasoline caught fire near Pago Pago island. The vessel later sank.
In Scammon Bay on Alaska’s western shore, an oil storage container failed, releasing up to 7,000 gallons of gasoline. The oil could be observed as sheens on the nearby river.
Resource Watch features NOAA’s daily updates on oil and chemical spills. So far, there have been five oil spills in 2019. You can monitor the last 30 days of data on Resource Watch and sign up for alerts here.