The best place is on the U. S. Department of Transportation website. The Pipeline and Hazardous Materials Safety Administration (PHMSA) is responsible for regulating and ensuring the safe and secure movement of hazardous materials to industry and consumers by all modes of transportation, including pipelines. Look for a partner, like Lynden, who has hazmat and dangerous goods transportation experience. They can serve as an excellent resource to ensure your goods are properly marked and documents are correct.