# NTSB Safety Recommendation P-93-018 **Citation:** P-93-018 **Type / status:** guidance / guidance **Agency:** National Transportation Safety Board **Effective:** 1993-12-15 **Published:** 1993-12-15 THE NTSB RECOMMENDS THAT THE AMERICAN PETROLEUM INSTITUTE: EXPEDITE COMPLETION OF THE RECOMMENDED SAFETY PRACTICE FOR THE DESIGN, CONSTRUCTION, OPERATION, AND MAINTENANCE OF SOLUTION-MINED STORAGE CAVERNS. ## Document text NTSB safety recommendation P-93-018. THE NTSB RECOMMENDS THAT THE AMERICAN PETROLEUM INSTITUTE: EXPEDITE COMPLETION OF THE RECOMMENDED SAFETY PRACTICE FOR THE DESIGN, CONSTRUCTION, OPERATION, AND MAINTENANCE OF SOLUTION-MINED STORAGE CAVERNS. Priority: CLASS II Overall Status: Closed - Acceptable Action Issued Date: 1993-12-15 Adopted Date: 1993-11-04 Overall Date Closed: 1995-02-24 Synopsis: ON APRIL 7, 1992, AN UNCONTROLLED RELEASE OF HIGHLY VOLATILE LIQUIDS (HVLS) FROM A SALT DOME STORAGE CAVERN IN THE SEMINOLE PIPELINE SYSTEM NEAR BRENHAM, TEXAS, FORMED A LARGE, HEAVIER-THAN-AIR GAS CLOUD THAT EXPLODED. THREE PEOPLE DIED FROM INJURIES SUSTAINED EITHER FROM THE BLAST OR IN THE FIRE. AN ADDITIONAL 21 PEOPLE WERE TREATED FOR INJURIES AT AREA HOSPITALS. DAMAGE FROM THE ACCIDENT EXCEEDED $9 MILLION. Probable Cause: None Ntsbnumber: DCA92MP006 Report Number: PAR-93-01 Addressee Name: American Petroleum Institute Addressee Status: Closed - Acceptable Action Addressee Date Closed: 1995-02-24 Addressee Acronym: API Addressee Organization Type: A-Associations Communication Date: 1994-01-12 Communication Type: Official Correspondence Communication Contents: API IS CURRENTLY DEVELOPING TWO STANDARDS ON SOLUTION-MINED STORAGE CAVERNS. RECOMMENDED PRACTICE 1114, DESIGN OF SOLUTION MINED UNDERGROUND STORGE FACILITIES HAS BEEN SUCCESSFULLY BALLOTED AND SHOULD BE PUBLISHED IN MARCH 1994. RECOMMENDED PRACTICE 1115, OPERATION OF SOLUTION MINED UNDERGROUND STORAGE FACILITIES HAS RECENTLY BEEN BALLOTED BY THE GENERAL COMMITTEE ON PIPELINES. Addressee Acronym: API Addressee Organization Type: A-Associations Communication Date: 1994-07-27 Communication Type: Official Correspondence Communication Contents: I AM PLEASED TO REPORT THAT API RECOMMENDED PRACTICE 1114, DESIGN OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES, HAS BEEN PUBLISHED. IN ADDITION, THE TECHNICAL WORK ON API RECOMMENDED PRACTICE 1115, OPERATION OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES, HAS BEEN COMPLETED. WHEN THE RECOMMENDED PRACTICE IS PUBLISHED WE WILL SEND YOU A COPY. Addressee Acronym: API Addressee Organization Type: A-Associations Communication Date: 1994-11-02 Communication Type: Official Correspondence Communication Contents: ENCLOSED ARE TWO COPIES OF API RECOMMENDED PRACTICE 1115, OPERATION OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES. Addressee Acronym: API Addressee Organization Type: A-Associations Communication Date: 1994-02-22 Communication Type: Official Correspondence Communication Contents: THE BOARD UNDERSTANDS THAT THE API IS CURRENTLY DEVELOPING TWO STANDARDS, RECOMMENDED PRACTICE 1114 AND 1115, ON SOLUTION-MINED STORAGE CAVERNS. PENDING THE ACTUAL DEVELOPMENT OF THESE STANDARDS, RECOMMENDATION P-93-18 WILL BE CLASSIFIED AS "OPEN--ACCEPTABLE RESPONSE." Addressee Acronym: API Addressee Organization Type: A-Associations Communication Date: 1994-10-17 Communication Type: Official Correspondence Communication Contents: THE BOARD APPRECIATES RECEIVING A COPY OF THE API'S RECOMMENDED PRACTICE 1114, "DESIGN OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES." IT COVERS ALL ASPECTS OF SOLUTION-MINED UNDERGROUND STORAGE, INCLUDING SELECTING THE SITE, DEVELOPING THE CAVERN, TESTING, & COMMISSIONING THE CAVERN. WE ALSO UNDERSTAND THAT THE TECHNICAL WORK ON API RECOMMEDED PRACTICE 1115, "OPERATION OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES," HAS BEEN COMPLETED. PENDING OUR REVIEW OF RECOMMENDED PRACTICE 1115, P-93-18 IS CLASSIFIED "OPEN--ACCEPTABLE RESPONSE." Addressee Acronym: API Addressee Organization Type: A-Associations Communication Date: 1995-02-24 Communication Type: Official Correspondence Communication Contents: THE BOARD HAS REVIEWED THE API DESIGN OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES & OPERATION OF SOLUTION-MINED UNDERGROUND FACILITIES. THESE PUBLICATIONS PROVIDE GUIDANCE FOR THE DESIGN & CONSTRUCTION OF SOLUTION-MINED STORAGE CAVERNS & GUIDANCE ON THE OPERATION OF SOLUTION-MINED UNDERGROUND GAS STORAGE FACILITIES, RESPECTIVELY. BASED ON THESE API PRATICES, P-93-18 HAS BEEN CLASSIFIED "CLOSED--ACCEPTABLE ACTION." ## Provenance - Official: Yes - Source: - Source ID: `ntsb-pipeline` - SHA-256: `2402beb186d4de018b8ebc31db36f1e784e325ab5acee2fa7f38d348001510ac` - Retrieved: 2026-08-20T04:57:24.741Z - Exported: 2026-08-22T06:37:58.468Z - Document slug: `ntsb-recommendation-p-93-018` ### Source metadata ```json { "recordKind": "ntsb_safety_recommendation", "safetyRecommendationNumber": "P-93-018", "recommendationMode": "Pipeline", "topicMode": "Pipeline", "ntsbNumber": "DCA92MP006", "priority": "CLASS II", "overallStatus": "Closed - Acceptable Action", "overallStatusAcronym": "CAA", "overallDateClosed": "1995-02-24", "lastModifiedDate": "2016-11-15", "reportNumber": "PAR-93-01", "reportUrl": "https://www.ntsb.gov/investigations/Pages/DCA92MP006.aspx", "transmittalLetterUrl": "http://www.ntsb.gov/safety/safety-recs/recletters/P93_18_20.pdf", "addressees": [ { "addresseeName": "American Petroleum Institute", "addresseeStatusAcronym": "CAA", "addresseeStatus": "Closed - Acceptable Action", "addresseeDateClosed": "1995-02-24", "addresseeDetails": [ { "addresseeAcronym": "API", "addresseeOrganizationType": "A-Associations", "isFromNtsb": false, "communicationDate": "1994-01-12", "communicationType": "Official Correspondence", "communicationContents": "API IS CURRENTLY DEVELOPING TWO STANDARDS ON SOLUTION-MINED STORAGE CAVERNS. RECOMMENDED PRACTICE 1114, DESIGN OF SOLUTION MINED UNDERGROUND STORGE FACILITIES HAS BEEN SUCCESSFULLY BALLOTED AND SHOULD BE PUBLISHED IN MARCH 1994. RECOMMENDED PRACTICE 1115, OPERATION OF SOLUTION MINED UNDERGROUND STORAGE FACILITIES HAS RECENTLY BEEN BALLOTED BY THE GENERAL COMMITTEE ON PIPELINES." }, { "addresseeAcronym": "API", "addresseeOrganizationType": "A-Associations", "isFromNtsb": false, "communicationDate": "1994-07-27", "communicationType": "Official Correspondence", "communicationContents": "I AM PLEASED TO REPORT THAT API RECOMMENDED PRACTICE 1114, DESIGN OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES, HAS BEEN PUBLISHED. IN ADDITION, THE TECHNICAL WORK ON API RECOMMENDED PRACTICE 1115, OPERATION OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES, HAS BEEN COMPLETED. WHEN THE RECOMMENDED PRACTICE IS PUBLISHED WE WILL SEND YOU A COPY." }, { "addresseeAcronym": "API", "addresseeOrganizationType": "A-Associations", "isFromNtsb": false, "communicationDate": "1994-11-02", "communicationType": "Official Correspondence", "communicationContents": "ENCLOSED ARE TWO COPIES OF API RECOMMENDED PRACTICE 1115, OPERATION OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES." }, { "addresseeAcronym": "API", "addresseeOrganizationType": "A-Associations", "isFromNtsb": true, "communicationDate": "1994-02-22", "communicationType": "Official Correspondence", "communicationContents": "THE BOARD UNDERSTANDS THAT THE API IS CURRENTLY DEVELOPING TWO STANDARDS, RECOMMENDED PRACTICE 1114 AND 1115, ON SOLUTION-MINED STORAGE CAVERNS. PENDING THE ACTUAL DEVELOPMENT OF THESE STANDARDS, RECOMMENDATION P-93-18 WILL BE CLASSIFIED AS \"OPEN--ACCEPTABLE RESPONSE.\"" }, { "addresseeAcronym": "API", "addresseeOrganizationType": "A-Associations", "isFromNtsb": true, "communicationDate": "1994-10-17", "communicationType": "Official Correspondence", "communicationContents": "THE BOARD APPRECIATES RECEIVING A COPY OF THE API'S RECOMMENDED PRACTICE 1114, \"DESIGN OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES.\" IT COVERS ALL ASPECTS OF SOLUTION-MINED UNDERGROUND STORAGE, INCLUDING SELECTING THE SITE, DEVELOPING THE CAVERN, TESTING, & COMMISSIONING THE CAVERN. WE ALSO UNDERSTAND THAT THE TECHNICAL WORK ON API RECOMMEDED PRACTICE 1115, \"OPERATION OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES,\" HAS BEEN COMPLETED. PENDING OUR REVIEW OF RECOMMENDED PRACTICE 1115, P-93-18 IS CLASSIFIED \"OPEN--ACCEPTABLE RESPONSE.\"" }, { "addresseeAcronym": "API", "addresseeOrganizationType": "A-Associations", "isFromNtsb": true, "communicationDate": "1995-02-24", "communicationType": "Official Correspondence", "communicationContents": "THE BOARD HAS REVIEWED THE API DESIGN OF SOLUTION-MINED UNDERGROUND STORAGE FACILITIES & OPERATION OF SOLUTION-MINED UNDERGROUND FACILITIES. THESE PUBLICATIONS PROVIDE GUIDANCE FOR THE DESIGN & CONSTRUCTION OF SOLUTION-MINED STORAGE CAVERNS & GUIDANCE ON THE OPERATION OF SOLUTION-MINED UNDERGROUND GAS STORAGE FACILITIES, RESPECTIVELY. BASED ON THESE API PRATICES, P-93-18 HAS BEEN CLASSIFIED \"CLOSED--ACCEPTABLE ACTION.\"" } ] } ], "jurisdiction": "US" } ```