I just heard an update, and they said the parking lot wasn't for employees of the VALERO plant, but contractors working on some special project that sounded like hydrocracking..

[link to www.bloomberg.com]

from wiki

Hydrocracking
In 1920, a plant for the commercial hydrogenation of brown coal was commissioned at Leuna in Germany.[5]
Hydrocracking is a catalytic cracking process assisted by the presence of an elevated partial pressure of hydrogen gas. Similar to the hydrotreater, the function of hydrogen is the purification of the hydrocarbon stream from sulfur and nitrogen hetero-atoms.
The products of this process are saturated hydrocarbons; depending on the reaction conditions (temperature, pressure, catalyst activity) these products range from ethane, LPG to heavier hydrocarbons consisting mostly of isoparaffins. Hydrocracking is normally facilitated by a bifunctional catalyst that is capable of rearranging and breaking hydrocarbon chains as well as adding hydrogen to aromatics and olefins to produce naphthenes and alkanes.
Major products from hydrocracking are jet fuel and diesel, while also high octane rating gasoline fractions and LPG are produced. [6] All these products have a very low content of sulfur and other contaminants.
It is very common in Pakistan, Europe and Asia because those regions have high demand for diesel and kerosene. In the US, Fluid Catalytic Cracking is more common because the demand for gasoline is higher.