Since approximately 9 pm, Tuesday night, numerous Delaware County and New Castle County, DE companies were out investigating a strong odor of gasoline in several homes in the area of Cherry Tree Rd. and Clearview Ln. in Aston Twp. The source of the odor was believed to be originating from a petroleum leak at the nearby Conoco-Phillips tank farm, which was possibly travelling through the sewer system and releasing fumes into several area homes. Due to the unusual size and duration of the incident, cover companies were called in to stand-by for several hours before proceeding into the scene and being replaced by other cover companies. Eventually, shortly before 1 pm on Wednesday afternoon, Engine 20-2 was dispatched to cover Company 72 (Aston-Beechwood). The engine relocated under the command of D/C 20-9A (M. Morgan). After standing by for about 3 hours, 20-2 was called into the scene to assist with the investigation, and to monitor the situation in some of the affected homes. 20-2 was released from the scene around 9 pm. Companies assisted from as far away as Montgomery and Chester Counties and worked well together to keep the situation under control. The source was eventually confirmed to be a leak from the nearby tank farm pipeline, and Companies began clearing up; some after well over 24 hrs. on the scene.