Crews reopen two lanes of Highway 17 N after roadway spill near Isle of Palms Police say they aren’t exactly sure what type of mud fell off the dump truck, but officers are inspecting the source. (Source: The Mount Pleasant Police Department) By Riley Bean | May 17, 2021 at 11:47 AM EDT - Updated May 17 at 12:38 PM MOUNT PLEASANT, S.C. (WCSC) - The Mount Pleasant Police Department says they are cleaning up US 17 after a truck spilled construction mud on the roadway. Police say they aren’t exactly sure what type of mud fell off the dump truck, but officers are inspecting the source.