LyondellBasell officially broke ground on what will be the largest propylene oxide (PO) and tertiary butyl alcohol (TBA) plant ever built. The Houston area project is estimated to cost $2.4 billion, representing the single-largest capital investment in the company's history. Once in operation, the plant will produce 1 billion pounds (470,000 metric tons) of PO and 2.2 billion pounds (1 million metric tons) of TBA annually. Startup of the plant is planned for 2021. Two facilities will be constructed on existing manufacturing sites.