This enforcement action was filed in response to violations of CERCLA 103A resulting from an ethyl ether release at Equistar's Tuscola, IL facility. On 2/28/2011, a process line pressure relief valve at the Tuscola facility began venting ethyl ether to the atmosphere. The total amount of ethyl ether released was 555 lbs or approximately 5.5 times this chemical's reportable quantity (RQ) of 100 lbs. Equistar didn't notify the NRC of this release until 3/1/2011 - approximately 23 hours and 41 minutes after the release began. The NRC should be notified of releases no later than 15 minutes following their discovery.