Document RmxnYvKKBZva6mzyJk0xLN7v

1\ w /a i "\~i ('.-ii ni> r' y. Interoff ce Communication To I. A. DeBernardi From Date t. W. Ware September 17, 1980 Subject Jnexpected VCM Release - September 11, 1980 Summary On Septemb sr 11, 1980, at approximately 1400 hours, an unexpected release of vinyl c iloride to the atmosphere occurred. The release occurred at BL-304 (so jth "super sucker"), and was caused by operator error. Approximaterly 10) gallons of vinyl chloride were released. It is estimated, with reaso lable confidence, that 11 individuals were exposed to vinyl chloride a Dove the permissible levels. Circumstances Leading Up to the Release At approxi nately 1400 hours on September 11, 1980, W. V. Henry, J. W. Ware, C. W. Turn er and D. Ross were preparing to enter T-204. Ross was in the process of checking the explosivity and oxygen content of the gases in the tank. Rosls and Ware, kneeling at the T-204 manway, detected an odor which both concl uded was propylene (not an unusual odor to be detected at this parti :ular location). J. Puerta called Ross over the paging system, Ross, in p roceeding to the nearest phone, noticed that the furnace water curtain wa on, indicating a flanmable gas leak in the plant. Ross ran to the pho ne and talked to Puerta; Puerta confirming detection of a gas leak. proceeded down the stairs at the east end of the oxy section and encountered a vinyl spill at the south "super sucker", BL-304. Immediately recognizi ng the source of the leak, Ross held his breath and proceeded to close the vinyl valve at the vinyl dryer, S-207B. Ware, noticing that Ross was alairtned then also noticed the water curtain at the furnaces and pointed this out t o Henry and Turner. Ware, Turner, and Henry then followed Ross down the o xy stairs and, recognizing the source of the release, reversed direction, escaping the release via the stairs west of the oxy reactors. R. Handy, prior to the release, was occupied with the task of inventorying S-207B vi n|yl dryer. Basic procedure is to isolate the dryer, purge it with nitrogen, leak check it with nitrogen, pressure it up with vinyl and vent the inerts to the incinerator (see Appendix A), Handy had neglected to close the atmospheric vent line leading to the 1 super sucker" prior to charging dryer with vinyl (see Appendix B). This resulted in the vinyl release, Handy was on the overhead vinyl dryer check when he observed Ross running d cw n the oxy stairs. Handy used his portable radio to call the main control rdom without response. A second call to the incinerator was acknow- ledged. he incinerator operator, R. Badolato, then called the main control room perso nnel to inform them of the problem. Handy closed the dryer/ incinerato vent valve at approximately the same moment that Ross closed the dryer vinyl valve. sal 0909x7 J. A. DeBernaifdi Page 2 January 22, 1 $81 Circumstances Following the Release Ware, Turner, Henry, Ross and Handy convened cross-wind of the release where Ross had open{ d a fire monitor to deluge the source of the release to prevent the forme tion/ignition of a flammable mixture. Personnel then dispersed: He nry proceeded to open the fire monitor south of C-202; Ware proceeded to (jipen the fire monitor south of the furnaces; Turner proceeded to open the f re monitor(s) in the ethylene unit. Henry contacted the main control room ^nd instructed the board operator to announce over the paging system that a 1 process areas were to be evacuated. Lab personnel were informed that high vinyl readings required their evacuation. The ethylene plant control room was also informed of the emergency. A. C. Hughes had arrived at thi scene and opened the fire monitor east of the control room. These action $teps appeared to be sufficient to secure plant personnel and equipment frorfi immediate harm. Henry proceeded to the control room to monitor ambie r|it vinyl chloride levels in the process area via the fixed point monitor systeiji The remaining personnel in the unit proceeded to assure confinement O' all vinyl at the vinyl dryer, assisted by H. Adkison. Henry called Ware over the paging system after he arrived at the control room to inform Wa re that ambient concentrations of vinyl chloride above the permissible 1 <vel were still present in the unit (18 ppm at C-203 and 30 ppm at C-201). Sii tisfied that the immediate hazard had diminished. Ware informed Ross that all further work in the unit would require respiratory protection until ambient vinyl chloride concentrations were confirmed to be below the permissible 1 evel (1 ppm). Ross and crew donned protective equipment to further secure the process unit. Ware and Turn <?r joined Henry in the control room. A preliminary survey of the plant ind cated that a satisfactory evacuation had been accomplished, TLV analysis ndicated that control room levels of vinyl chloride did not require breathing air use. Turner donned a Scott Air Pak and retrieved a Drager analyzer from atop T-204. Henry utilized this unit to back up the TLV and confirm that the control room levels of vinyl chloride were indeed acceptable. While retrieving the Drager analyzer Turner surveyed the process unit with a TLV and found various concentrations of vinyl chloride ranging from 1200+ ppm in Slock II to 300 ppm atop T-204 (see Diagram #1, Appendix C). At 1430 hours Turner donned a second Scott Air Pak and surveyed in detail the entire un t to determine the extent of the area affected by high vinyl chloride cone dntrations (see Diagram 2, Appendix C). The ethylene unit foreman was tli en contacted by Ware and informed that no one should enter his unit withd ut respiratory protection. The foreman stated that he would call all of h s people to the control room. Vinyl chloride levels in the ethylene area was monitored during the incident with the results being that shown in Appeh dix D. 918 000090 0. A. DeBerna 'di Page 3 January 22, 1 >81 The vinyl chi )ride levels were then monitored in the unit using the fixed point monitor system in the control room. When, according to this system, vinyl chlorid 3 levels had lowered to 1 ppm or less. Turner was sent out with a TLV unit (wfithout breathing air) and instructed not to trespass in an area which sh owed a reading approaching 5 ppm (see-Diagram #3, Appendix C). Diagram #4, Appendix C shows a fourth survey conducted by Turner. The "all clea r" was given at 1602 hours on September 11, 1980. Employee Expo sure Nine Conoco employees and two contractor employees were temporarily exposed to vi nyl chloride vapors. Seven Conoco employees were exposed while responding tc the immediate emergency. The two contractor employees were ex posed during evacuation. Two Conoco laboratory employees were also exposed during the ev acuation. Medical Surve illance To date no ac verse physical affects on any of the exposed individuals have been noted, All exposed individuals were informed.verbally and by letter of their expc sure to vinyl chloride. In addition, medical examinations were made availabl to the exposed individuals should they desire one. Recommendatic ns and Conclusions The basic cau se of the release was the unrestricted flow of vinyl chloride from S-207B ito the BL-304 atmospheric vent. The underlying cause of the release was qperator error. In order to prevent a recurrence of this incident the following will be instituted: 1) flinds will be installed in the "super-sucker" lines at the vinyl dryers (see Appendix E). On each dryer the associated hiind will be removed only after the dryer has been cleared End depressured and will be installed before the dryer is returned to the Operations Department following any Maintenance work. This added restriction will be written into the existing dryer clearing procedure. 2) he revised clearing procedure will be issued and reviewed \nith both Maintenance and Operations personnel. Mi seel 1aneous Appendix F contains letters of notification for 05HA and EPA. J. W. Ware SfitL oooo909 APPENDIX A PROCEDURE FOR CLEARING S-207 FOR RECHARGE 1) Line up ()pen valve) from S-206 to down-stream dryer. 2) Close valve from 5-206 to up-stream dryer. 3) Open the valve on the bottom of the up-stream dryer. This will enable you to emoty dryer into the line coming from S-205. 4) Close the outlet valve on the up-stream dryer. This isolates the upstream dryer with only the bottom valve open. 5) Open nitrogen to top of up-stream dryer. Open nitrogen slowly so as not to in crease pressure on S-206 by more than 10-12 psig. 6) Watch for level to come down into the sight glass. When the level goes out of si ght glass, wait about one minute (no more) then close the bottom valve. 7) Contact i ncinerator operator, then slowly depressure dryer to S-108. (leave ni trogen cracked in on top while depressuring). 8) Pressure dryer up with nitrogen to 50 psig and depressure three times, During t\ is step, also open nitrogen to spargers, and depressure through sight gl c s s to clear. Will have to keep in close contact with incinerator operator. 9) After No. 8 step, block in nitrogen going to the spargers, and with a positi \|e pressure on the dryer sample for lab analysis. If analysis is less t[han 2% vinyl, depressure completely. If analysis is more than 2% vinyl continue step 8 until an acceptable analysis is obtained. 10) After st4p 9 is complete, open the 2 valves going to the super sucker from the spargers, put the supersucker on and open the nitrogen wide open to the top of the dryer. After five minutes cut the nitrogen back to minimum and open the vent valve in the line to the supersucker. 11) Maintenance will open the dryer and then close the vent valve before recharging. 12) When redfi arge is complete, shut down supersucker and close the two valves from spa rgers to the supersucper. Pressure the dryer up to 75-100 psig with nitf ogen, and leak check top manway. If there are no leaks, depressure and pressure up to 50 psig two more times and depressure. Dryer is now ready to put in service. Oo,9920 13) Open val Vi (barely crack open) from top of dryer in service, to spargers of the dr,' er you are putting in. service. Do not lower pressure on S-206 more than 10-12 psig during this step. 14) When press;ure is equalized, open the valve to spargers wide open. Call incineratpir operator, and slowly bleed nitrogen out of top of dryer to wet vent, When dryer is liquid full, put in service second in line, by opening t D)p valve to the check tanks and closing the valve to the check tan <;. s from the upstream dryer. 000090921 SAL APPENDIX B v SfilL 0000909 APP^^iy. e> iTKO ^ASv^v C_ ZTZV.T^T Vimyl. W^L-OcL. ViNr<\_ _. VAL.0^ "1 SAL 000090923 APPENDIX C SAL 000090924 A uJirt fg It <t 0 rt vfl ^LXJ *T; n yi tJ Oti looo -*_____ "n q AS______ / o o ClZD -J$ in $ fl w>! s_____ O 8 & P! r^\ 6 vj # AU 00009092^ A>A6A>^ SAL 000090926 SAL 000090927 _ce>*irr.c>i_ 3 SAL 000090928 V V. appendix d /' 000090929 % Interoffi ce Ccmmunicaticn To P. L. Jernigan From S. F. Pitts Date September 22, 1980 Subject VCM Contamination Four air simples were taken in the Ethylene Unit area during the VCM release on September 11, 1980. The samples were taken over a period of 2.3 hours with the following results. Sample Code VC-007 VC-008 VC-009 VC-010 Location Cz Control Room Chem Storage West of Quench Fence Line West of Spent Caustic Tank South Side C2 Control Room If you/^av^ any que^f let me know. >/ Sidney Pit Safety Di ;or Lake Chftf'l :S Chemical Plant maa cc: R. D. Gamblin W. V. Henry -C o- Result (ppm VCM) 0.08 1.49 8.69 0.47 to ,, S" 30 PK 000090930 appendix e SAL 000090931 ZTIMCNT vira-nVAuV^ - SAL 00009093 APPENDIX F SAL 00009093 / \ Lak* Charles VC M Plant CERTIFIED MAIL *315658 RETURN RECEIPT REQUESTED September 1 5, 1980 - -- -i ; v J ! Conoco Chemicals Company A Division of Conoco Inc. P.0 Box 605 Westlake, Louisiana 70669 13181 491-5211 U. S. Depar mient of Labor Occupationa Safety & Health Administration 2156 Woodda e Boulevard Hoover Annexe , Suite 200 Baton Rouge LA 70806 Attention: Joe Amsley, Area Director Gent!emen: This letterlis in confirmation of a report submitted by telephone on September l:!, 1980 at approximately 1:45 p.m. with regard to an unexpected release of vinyl chloride monomer. Mr. Henry Ramos, Industrial Hygienist, was the 0SHA representative I talked to. This report is being submitted in compliance yith Part 1910.1017 of the OSHA Vinyl Chloride Standard. At approxim dtely 2 p.m. on September 11, 1980, an unexpected release of vinyl chloride to the atmosphere occurred at the Conoco Chemicals Company's Vinyl Chloride PI int in Westlake, Louisiana. The release resulted from the fact that a valv in an atmospheric vent line on a vinyl chloride dryer was in advertently left open while the dryer was being inventoried with product, Approximate y 100 gallons of vinyl chloride was released to the atmosphere before the ,rent valve was closed. Seven employees in the immediate vicinity of the rele;. se who responded to the emergency were exposed to vinyl chloride vapors in tli e process of successfully suppressing the potential ignition of the released vapors. Upon alleviation of the immediate fire hazard, all employees i involved retreated to a safe location to don'respiratory equipment, monitor the situation, and plan appropriate action. Immediately upon recognition that a release had occurred, all non-essential personnel were evacuated to a safe location and essential personnel were either located in areas confi fmed to be below the permissible levels or required to don respiratory equipment. The plant areas were monitored for vinyl chloride levels with portable thr eshold limit value detectors, fixed point monitor gas chromotograph analy ers and a Drager tube analyzer until the concentration of the vinyl chloride wa below the permissible level and employees were allowed to return to their rou tine duties. In addition to the seven employees mentioned above, two other employees and two other contre ct employees were exposed to vinyl chloride vapors during the evacuation, Employees responding to the emergency in the process area were exposed to i inyl chloride vapors for approximately five minutes. SAL 00009093A U. S. Depa'tinent of Labor Page 2 September 15, 1980 In accorda ice with the Vinyl Chloride Standard, the above-mentioned exposed employees lave been verbally notified that they were exposed to vinyl chloride above the lermissible level- This verbal notification will be followed within ten days by written confirmation to these employees. Because of the personnel1 short time of exposure and the absence of any physical effects, our Medical Division rcommended that no immediate medical a-ttention was warranted. Sincerely, W. V. Henry Safety Dir JCtor is BCC: VCM File J. J. Hall - Houston JAD 000090935 SAL