Toxic Drug Tanker

S3 E11: At the southernmost tip of Texas is the Rio Grande Valley - a vast and sparsely populated region. As Mexican drug cartels expand their reach north of the border, the US Department of Homeland Security must rely on every available resource to find and apprehend smugglers and illegal immigrants. Border Patrol agents - tipped off by electronic sensors or covert surveillance - chase illegal immigrants through the dense brush of the river valley in vehicles or on foot. At the Falfurrias Station, smugglers bury drugs deep inside the toxic chemical cargo of tanker trucks, requiring highly trained Hazmat teams to uncover them. And at the seaport in Brownsville, shipping vessels from across the globe are scrutinized for threats ranging from bomb-making materials to deadly insects which could decimate US agriculture.