you're in Pittsburg, are they drilling for oil or for natural gas? They may be actually drilling for natural gas and using a technique called fracking. With fracking they pump a sorta hydrolic fluid into the ground to force up the gas (from the Marcellus Shale). That could have the consistency you describe but shouldn't come up in your basement, that stuff should be down thousands of feet, below the water table, below the oil.
yeah, I would go talk to the person in charge across the street.