Please note that clay is a natural substance that comes from the earth but it does not come in the form of a gel. For that, they mix it with hydrocarbons.
November 18, Associated Press – (Pennsylvania) Drilling halted after spill into NW Pa. reservoir.
Also note the date of the spill.
A company has halted Marcellus drilling in one northwestern Pennsylvania town after a kind of clay used to expedite the process spilled into a local reservoir, the Associated Press reported November 17. Hunt Marcellus Operating Co.
told the Bradford Era it stopped drilling in Johnsonburg after some bentonite gel was released into Silver Creek and made its way into a drinking water reservoir controlled by the Johnsonburg Municipal Authority. It was not immediately clear how much of the substance got into the reservoir. The water authority chairman said the substance is
not expected to affect the safety of the water because bentonite is a “non-toxic substance that comes from the earth.”
UPDATE: Here’s a little movie for commenter BD to watch about bentonite clay that Devon used for drilling. It ended up in this water well so we had it tested.