NTSB Safety Recommendation Letter P-74-050 through P-74-058

Page 1Official PDFL. i I / / / I - i - 23 - 5. Although i n the Conway accident the block valve a t Conway was reported t o have been i n i t i a t e d t o the open position and i t f a i l e d t o open, no reason f o r the f a i l u r e t o open could be found, and no r e p a i r s t o the system were made. 6, The v i s i b l e vapor cloud i n the Conway accident i n t o which the trucks were driven w a s not pure a m n i a , because concentrations of 0.5 percent would have been l e t h a l t o both truckdrivers. The vapor cloud probably cansisted mostly of water vapor produced by condensation from t h e air, c h i l l e d by expansion and vaporization of the high-pressure “3. 7. MAKO did not a c t i n conformance with Federal regulation 49 CFR 195 i n t h a t it did not report t h i s accident by telephone and it did not have a couununications system that insures t h e transmission of informa- t i o n required f o r the s a f e operation of its pipeline system. 8. The Federal regulation, 49 CFR 195.260, Valves: Loca- t i o n (c), is vague and d i f f i c u l t t o enforce, because i t permits each pipeline operator t o be the judge of the adequacy of valve spacing. PROBABLE CAUSE The National Transportation Safety Board determines t h a t the probable cause of the pipeline rupture a t Conway was the above-nom1 pressure on a s e c t i o n o f p i p e whichhadbeen weakenedbyprevious damagebyoutside forces. Contributing t o the above-normal pressure w a s the f a i l u r e of the dispatcher t o insure that the l i n e block valve a t Conway was open a f t e r he s t a r t e d the pump at Borger. Contributing t o the amount of anhydrous a m n i a s p i l l e d were the delay i n shutting down the correct pipeline, the distance between l i n e block valves, the time taken to manually close the existing block valve, and the highly v o l a t i l e c h a r a c t e r i s t i c s of the escaping product. Contributing t o the delay i n shutting dawn the correct pipeline w a s the lack of any pressure-sensing devices on the upstream s i d e of the l i n e block valve at Conway. RECOPFIENDATIONS The National Transportation Safety Board reconmends t h a t the Office of Pipeline Safety of the Department of Transportation: 1. In its upcoming rulemaking action f o r the transportation o f highly v o l a t i l e , toxic, or corrosive l i q u i d s , include anhydrous a m n i a pipeline systems. Particular emphasis should be placed on a reduction of the maximum allowable pressures f o r “3#

Page 2- 24 - J - 6/ - 7 / s y s t e m , more close1,y spaced valves, and mre remotely or auto- matically operated valves. (Recommendation No. P-74-50) 6/ 2 . I n i t s consideration t o take regulatory action concerning the methods of handling, containing, and disposing of liquefied pet- roleum gases, include "3. Necessary information should be ob- tained from the OPS study on highly v o l a t i l e , toxic and/or cor- rosive liquids currently underway. Rulemaking should take i n t o account such external f a c t o r s as weather conditions, leak site topography, and population density. Attention should begiven t o ! the local temperature inversions caused by the rapid expansion i of the escaping "3 and the possible use of externally supplied heat and air blowers t o force t h e "3 vapors t o rise and d i s s i - ! pate. (Recotmendation No. P-74-51) I / 1 3. Amend CFR 49 195.404@), Maps and records, t o provide f o r pressure recording instruments t o be i n s t a l l e d and properly main- tained a t each pump s t a t i o n and each pipeline terminal and t h a t these recorded pressures be retained a t a c e n t r a l location f o r a t l e a s t 3 years. (Reconmendation No. P-74-52) 4. Amend 49 CFR 195 t o require l i q u i d petroleum pipeline operators t o establish l i a i s o n with appropriate public o f f i c i a l s , including fire and police o f f i c i a l s , t o b e t t e r inform them of tk character- i s t i c s and hazards of l i q u i d petroleum and related products. These regulations should include anhydrous a m n i a and should be similar t o those which appear i n 49 CFR 192, "Transportation of Natural and Other Gas by Pipeline; Minimum Safety Standards." (Recommendation No. P-74-53) 5. Require the Mid America Pipe Line Company to: (a) Improve i t s current written procedures under 49 CEX Section 195.402, General requirements, t o require t h a t dispatchers perform detailed monitoring of a l l points on a pipeline system d u r i n g s t a r t u p u n t i l conditions have s t a b i l i z e d . (P-74-54) (b) Check the instrumentation at a l l s t a t i o n s , terminals and con- t r o l points under 49 CFR Section 195.402 and make changes or additions as necessary t o protect t h i s pipeline system against overpressure. (?-74-55) (c) Reevaluate t h e i r training program f o r inspectors and t h e i r inspection procedures under 49 CFR 195.204, Inspection- This recoimnendation i s similar t o recommendations l ( a ) of NTSB-PAR- 72-1 and l ( a ) of NTSB-PAR-73-4. This recommendation is similar t o recommendation l ( d ) of NTSB-PAR- 72-1 and 1@) of NTSB-PAR-73-4.#

Page 3- 25 - general, t o increase t h e probability t h a t damage to t h e i r pipelines by outside p a r t i e s i s prevented or detected and reported. (P-74-56) I n i t i a t e a program for a mre specific inspection and r e p a i r program of the pipeline system pressure recording devices under 49 CFR 195.402 so t h a t they w i l l operate a s designed and intended i n a mre r e l i a b l e fashion. (P-74-57) R e v i e w the operations of the pipeline system i n the l i g h t of 49 CFR 195.402 t o i n s t i t u t e a mre systematic and a u t h o r i t a t i v e approach to understanding and controlling hazards. This review should cover the f u l l l i f e cycle of the pipeline system and be applicable t o the design of new pipelines, a s w e l l a s t o the operation and maintenance of existing pipelines. (Recommendation No. P-74-58) BY THE NATIONAL TRANSPORTATION SAFETY BOARD / s / JOHN H. REED Chairman / s / FRANCIS H. McADAMS I_ Member /s/ LOUIS M. THAYER Member f s f ISABEL A. B'LTRGESS Member f s l WILLIAM R . HALEY Member November 11, 1974#