NTSB Safety Recommendation Letter P-73-029 through P-73-036

Page 1Official PDF- 17 - 5. The lack of f a c i l i t i e s t o transmit the continously recorded l i n e p r e s s u r e s from t h e unattended pump s t a t i o n s t o t h e dispatching o f f i c e re- s u l t e d i n t h e d i s p a t c h e r s ' being u n a w a r e o f t r o u b l e i n t h e closed-in system. 6. A t t h e t i m e of the a c c i d e n t , Exxon was not i n conformance w i t h the i n t e n t of 49 CFR 195.408, Communications. This r e g u l a t i o n , however, is vague and t h e r e f o r e unenforceable, and i s not specifi.c enough t o guide p i p e l i n e companies to provide t h e c o r r e c t kind and amount of communicable information f o r t h e s a f e operation of p i p e l i n e s . 7. Unawareness on the p a r t of t h e d i s p a t c h e r s of any l i n e t r o u b l e from 12:30 a.m. u n t i l 6 : 2 0 a.m. r e s u l t e d i n t h e l a t e n o t i f i c a t i o n of t h e maintenance personnel and t h e subsequent f a i l u r e t o s h u t off t h e leaking crude o i l u n t i l a f t e r t h e explosion and f i r e . 8. The 4%-hour l a p s e between t h e l i n e r u p t u r e and t h e explosion allowed enough crude o i l t o escape t o f u e l a fire which temporarily severed a l l p i p e l i n e , r a i l r o a d , and te1,ephone communications and blocked the main highway i n t o Hearne from t h e south. 9. I f an undetected leak of t h i s n a t u r e had occurred i n a more densely populated area, numerous f a t a l i t i e s , more i n j u r i e s , and greater property damage would have occurred. L V. PROBABLE CAUSE i7 The National Transportation Safety Board determines t h a t t h e prob- a b l e cause of t h e explosion and f i r e w a s the i g n i t i o n of an accumulation of vapors from crude o i l which had sprayed from a shutdown, closed-in p i p e l i n e t h a t had been ruptured by excessive i n t e r n a l pressure. Contributing t o t h e excessive i n t e r n a l pressure were an i n c r e a s e i n t h e temperature of the crude o i l w i t h i n t h e pipe, t h e r e s u l t a n t expansion of the crude o i l , and t h e f a i l u r e by t h e p i p e l i n e company t o provide any p r e s s u r e r e l i e f f o r t h e closed-in p i p e l i n e system. Contributing t o t h e f a i l u r e of the p i p e was i t s thin-wall condition, caused by t h e corrosion of t h e unprotected b a r e steel walls. The lack of any Federal r e g u l a t i o n s t o r e q u i r e p e r i o d i c , h y d r o s t a t i c pressure t e s t i n g w a s a f a c t o r i n t h e p i p e l i n e rupture. The National Transportation Safety Board recommends t h a t : 1. The O f f i c e of P i p e l i n e Safety of t h e Department of Transportation: (a) R e v i e w t h e proposals made by t h e Hazardous Materials Regula- t i o n s Board i n Docket HM-6, and review t h e accident records of uncoated, unprotected, o r p a r t i a l l y protected p i p e l i n e s . Based upon t h e r e s u l t s of t h a t review, rulemaking should be undertaken t o provide f o r e i t h e r#

Page 2- 18 - p e r i o d i c h y d r o s t a t i c r e t e s t i n g of these p i p e l i n e s or progressive reduc- based uDon t h e e f f e c t s of continuine. t i o n i n their operating pressures I c o r r o s i o n , or both. (Recommendation No. P-73-29.) (b) Amend t h e 49 CFR 195.408, Communications, t o d e s c r i b e more f u l l y t h e type of information required f o r the s a f e operation of pipe- l i n e s and the conditions under which t h i s information should be trans- m i t t e d remotely. (Recommendation No. P-73-30.) 2 . The Exxon Pipe Line Company: (a) I n s t a l l pressure r e l i e f devices on this system and similar systems, i f a p p l i c a b l e , t o prevent a r e p e t i t i o n of t h e f a i l u r e of a closed-in system due t o overpressure. (Recommendation No. 7-73-31.) (b) I n s t a l l f a c i l i t i e s capable of remotely transmitting t h e con- tinuous recording pressures from the Comyn and Hearne pump s t a t i o n s t o the c e n t r a l dispatching o f f i c e . (Recommendation No. P-73-32.) (c) I n s t r u c t the dispatchers t o monitor c a r e f u l l y those lines which a r e closed-in and i n o p e r a t i v e t o preclude t h e p o s s i b i l i t y of over- pressure. (Recommendation No. P-73-33.) (d) I n i t i a t e a thorough cathodic p r o t e c t i o n survey over this sys- tem, from Hearne to Satsuma as a minimum, and a t random i n t e r v a l s uncover and physically inspect the p i p e , with p a r t i c u l a r emphasis on t h e known "hot spot" corrosion a r e a s . (Recommendation No. P-73-34.) (e) Add a d d i t i o n a l cathodic p r o t e c t i o n equipment, based upon the r e s u l t s of t h i s survey, t o m i t i g a t e t h e continuing e f f e c t s of corrosion on t h i s system. (Recommendation No. P-73-35.) (f) Not operate or c l o s e i n t h e Comyn t o Satsuma system from Hearne t o Satsuma at a pressure g r e a t e r than 400 p . s . i . g . , u n t i l a t least this s e c t i o n of l i n e has been h y d r o s t a t i c a l l y t e s t e d successfully and found t o be s a f e f o r higher operating pressures. (Recornendation No. P-73-36.) BY THE NATIONAL TRANSPORTATION SAFETY BOARD / s / JOHN H . REED Chairman I s / FRANCIS H. McADAMS Member / s / LOUIS M. THAYER Member / s / ISABEL A . BURGESS Member / s / WILLIAM R . HALEY Member August 1, 1973#