The Pipeline and Hazardous Materials Safety Administration is required by law to respond to safety recommendations issued by the National Transportation Safety Board (NTSB), an independent federal agency charged by Congress with investigating significant incidents that involve hazardous materials. Recommendations usually address a specific issue uncovered during an investigation or study and specify how to correct the situation.
Open Recommendations The NTSB has 6 classifications for open recommendations:
OAA - Open Acceptable Response
OAAR - Open Acceptable Alternate Response
OUA - Open Unacceptable Response
ORR - Open Response Received
OAR - Open Await Response
Closed Recommendations NTSB closes recommendations when it has been determined that sufficient actions have been achieved. NTSB organizes its closed recommendations into 7 classifications: