Rio Grande Oil Co Refinery is a superfund site located at West Of Ann St @ Sycamore St, Sour Lake, TX 77659. The Environmental Protection Agency (EPA) identifies sites such as Rio Grande Oil Co Refinery because they pose or had once posed a potential risk to human health and/or the environment due to contamination by one or more hazardous wastes. Rio Grande Oil Co Refinery is currently registered as an Archived superfund site by the EPA and does not require any clean up action or further investigation at this time.