CHELSEA TANK FARM GASOLINE RELEASE    

Source: https://chelseatankupdates.com/incident-details-background-of-issue/.

Visit this website or download the PDF for the full details of the incident.

"WHAT HAPPENED?

On August 18th, an MIPC operator noticed a faint odor while making routine checks in the northwest corner of our Chelsea Tank Farm. The source of the odor was determined to be a light gasoline and water mixture (approximately 2% gasoline to 98% water), emanating from a concrete stormwater drainage pipe. Upon discovery, MIPC immediately began implementing measures to contain and clean up the impacted water.

At the same time, MIPC notified state and county agencies, as well as municipal officials and our community emergency responders. MIPC also notified nearby neighbors in Bethel and Upper Chichester that there would be increased maintenance activity at the site. Additionally, fence line air quality readings were repeatedly taken, and results confirmed there were no impacts at the fence line of our facility.

INVESTIGATION PROCESS

After (MIPC's) initial mitigation efforts, MIPC began what would become a multi-month investigatory process to identify the source of the leak. Simultaneously, MIPC sought and received a PA Dep. of Environmental Protection permit to install a water treatment unit that has remained in operation to this day. Over the subsequent weeks, MIPC worked methodically to identify and rule out potential sources, which involved excavation of the concrete pipe, several soil digs (some to depths of 17 feet), numerous field tank valve and flange inspections, checking underground test stations, reviewing tank level data, and historical site data, and conducting static pressure tests and hydro tests of tanks in the impacted area. All investigatory efforts over this time did not yield a clear source or even the presence of a broader issue.

MIPC also provided regulatory agencies with updates and has complied with every request and recommendation conveyed to us.

SOURCE DISCOVERY

As (MIPC) continued to investigate the area of impact, (MIPC) installed soil borings (up to depths of 35 feet), and in early December, (MIPC) discovered gasoline impacted soil. In some cases, (MIPC) found gasoline impacted groundwater in one area of the site, including within 30 feet of our fence line. At this point, (MIPC) made notifications to all Federal, State and County agencies as well as municipal officials, emergency responders, and elected officials. MIPC also conducted door-to-door community outreach, notifying our fence line neighbors living within roughly 1,000 feet of the impacted area.

On December 13 , one of (the) storage tanks, which was previously taken out of service and emptied as part of this investigation, was confirmed to have a 1/4-inch hole in the interior floor. This discovery then initiated a process by which (MIPC) could calculate a maximum potential release total based on data and evidence. And this is how (MIPC) arrived at the potential total release of 9,000 barrels of gasoline in the northwest corner of our property, which (MIPC) reported to the Pipeline and Hazardous Materials Safety Administration (PHMSA)."

On Friday, May 1st, 2026, MIPC issued the following update regarding the ongoing gasoline release investigation at its Aston facility. For more information, including the background and timeline of the Chelsea Tank Farm leak, please visit:  MIPC Chelsea Tank Farm

   MIPC will continue to hold office hours every third Friday of the month in Bethel Township at the Myers Building (1092 Bethel Road, Garnet Valley, PA 19060) from 12:00 PM to 8:00 PM. Members of MIPC's community affairs team will be available to answer questions and provide information during these sessions. 

Additionally, weekly updates are dropped off at the Township building by MIPC for review.

New Documents Added

• Latest Weekly Progress Report – This was added to the ‘Remedial Action Plans & Other Technical Documents’ page.
• 5-1-2026 MIPC Statement – This was added to the ‘PA DEP Order & Communications’ page
• 5-5-2026 Neighbor Letter – Sorry We Missed You – This was added to the ‘PA DEP Order & Communications’ page