The Frequently Asked Questions below have been compiled and grouped by topic. 

In some cases, the same question and answer pair may be in more than one FAQ group to help you locate the information.

If you have trouble locating an answer to your question, please submit a new question through our Feedback Form.  PHMSA will review your question and respond to you.  If the answer to your question would be of interest to the users of this website, it may be included here in the future.