CARQUEST of Santa Fe has Sodium Silicate in stock.
Here is the wording from the NHTSA Final Rule document:
The agency has determined that a quick, inexpensive, and environmentally safe process exists to disable the engine of the trade-in vehicle while in the dealer’s possession. Removing the engine oil from the crankcase, replacing it with a 40 percent solution of sodium silicate (a substance used in similar concentrations in many common vehicle applications, including patching mufflers and radiators), and running the engine for a short period of time at low speeds renders the engine inoperable.
Dealerships looking for Sodium Silicate in the Santa Fe, NM area, can call CARQUEST Auto parts of Santa Fe @ (505) 984-8535.