NTSB Safety Recommendation Letter P-78-057

Page 1Official PDFP - / O 7 NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. ISSUED: August 28, 1978 Forwarded to: Mr. G.H. Lawrence President American Gas Association 153,5 Wilson Boulevard Arlington, Virginia 22209 \ I \ SAFETY R E C O M M E N D A T I O N ( S ) On March 29, 1978, the Oklahoma Natural Gas Company ( O N G ) dispatched a crew t o s h u t off gas service t o a shopping center i n Oklahoma Cit,y a t a regulator vault so t h a t customer service lines could be repaired. The crew was unable t o close a valve, inside the vault, t h a t was under water upstream of the regulator, so they disconnected the l i n e on the low-pressure side of the regulator a t a 2-inch union and plugged the line without f i r s t stopping the flow of gas. There was another valve outside the vault; however, i t was paved over with asphalt, and the crew did not attempt to uncover i t . On April 24, 1978, ONG assigned a different crew t o restore gas service t o the shopping center. A t 3:5O p.m., c.s.t., two employees were overcome by gas while attempting to reconnect the 2-inch union without first stopping the flow o f gas inside the vault. This crew also had not been able t o close the valve inside the vault upstream of the regulator, and they did not t r y t o uncover t h e valve outside the vault. Instead, the men had removed the plug and stuffed the l i n e with a rag. When the rag was pulled out, however, they were unable t o align the union properly to s t a r t the threads. The escaping gas f i l l e d the 3- by 4- by 6-foot vault within minutes and the men were overcome. Three other ONG employees entered the vault t h r o u g h the 19-inch opening t o rescue the men and were also overcome; the crew did not have a respirator a t the job s i t e . One man was pulled out of the vault by other ONG workers and was revived a t the scene; however, the other four men died o f asphyxiation. A mainline valve f i n a l l y was turned o f f , and rescue personnel with a i r packs arrived and removed the asphyxiated men from the vault. The f i v e men involved i n connecting the line in the vault had each been employed by ONG an average of 20 years, and three of them were supervisors. Although ONG has trained i t s men on the use o f air-breathing masks, ventilators, and l i f e b e l t s , the company does n o t have written instructions about where t h i s safety equipment shall be used. 2422#

Page 2The Safety Board concludes t h a t i f the ONG workmen had pumped the water out of the vault and made the valve operable, o r i f they had uncovered the valve outside the vault so t h a t it could be used t o stop the flow of gas before connecting the 2-inch union, this accident would not have occurred. The Safety Board has investigated similar accidents involving gas company employees who were overcome by gas while working i n a vault. I/ In many cases, senior gas men who were acquainted w i t h the hazarxs of n a t w a l gas were involved i n these accidents. Therefore, the National Transportation Safety Board recommends t h a t the American Gas Association: Advise i t s member companies of the circumstances o f this accident and urge them t o yeview t h e i r operating practices, procedures, and regulations related t o personnel working in confined areas. T h i s review should include both promulgation of procedures and enforcement a c t i v i t i e s . (Class I , Urgent Action) (P-78-57). KING, Chairman, McADAMS, HOGUE, and DRIVER, Elembers, concurred i n the above recommendation. - 1 / "Pipeline Accident Report--Equitable Gas Company, Pennsylvania, November 17, 1971," (NTS8-PAR-72-2) Gas Company accident, Buffalo, New York, March 26#