Document eBGz5eEvXKre5xqrJrLz0w4q

TELEPHONE HUDSON 3-6126 Manufacturing Chemists' Association, Inc. (FOUNDED 1872) 1825 Connecticut Avenue, N. W. Washington 9, D. C. Januarv 1964 Tasnf. TO THE EXECUTIVE CONTACTS OP MEMBER FIRMS SUBJECT: Case Histories of Accidents (including Fires and Explosions), Member firms are urged to send the MCA Washington Office an account of accidents (or near accidents) which they believe should be included in this report. Factual information on such occurrences is desired whether or not occupational injuries are actually involved, and regardless of the exact nature of their results. CASE HISTORY NO. 953 Cylinder Refilling Description: In the set-up in the safety de partment for refilling Pneolator Oxygen cylin ders, (21 cubic ft. capacity cylinders) the larger Oxygen cylinders from the supplier are used. ' Such cylinders are located on the out side of the building and connected by a 3000 lb. tested stainless steel tubing running through the wall and to directly over a work bench, a d^tance of approximately 15 feet to the valve. regulator is attached to the valve at this p^rat and the regulator that had previously been used was approximately 6*s years old. The gauges were not operating properly and it was decided that a new regulator would replace the older one. A new regulator was ordered from the manu facturer locally and when the same arrived was taken directly from the packing dox in which it arrived and placed on the valve. One hour pre vious to installation of the new regulator, the entire line leading from the large cylinder lo cated outside the building was blown out as a precaution and to eliminate any foreign materi als. This was done by opening the valve on the large Oxygen cylinder and blowing out same. When the new regulator was tightened and in place, the gauge on the outside cylinder was opened slowly and Oxygen was permitted to flow through the line and into the valve located in side the building which was closed. The in side valve was opened slowly and the gauge on the high pressure side of the regulator showed a pressure of between 2000 and 2100 lbs. on the gauge. This was permitted to stand this way for approximately 1 minute at which time the screw valve was turned to permit Oxygen t^Bflow to the low pressure side of the regu- When the screw valve had been turned clockwise about H turn, a terrific explosion occurred and belching flames and molten metal spewed over the immediate area. Molten metal from three holes in the regulator was found as far away as twenty feet. A pad of unused matches with the cover closed was lying on a table approximately 8 feet from the explosion. Investigation re vealed that all had been ignited within the pad and the cover was not even scorched. The safety director was turning the screw valve on the regulator and standing approximately 5 degrees to the left of cen ter of the regulator. The explosion blew one hole on the left side of the bell housing, another on the right and downward and another in the rear at the bottom of the flange. He received second and third degree burns on the right thumb and index fingers as this was the hand being used to turn the screw valve. His clothing was burned from hot metal. A safety inspector who had been outside to turn the valve on the large Oxygen cylinder had just walked in the door approximately fif teen feet away from the regulator when the ex plosion occurred. He was blown back out the door approximately 8 feet. (It might be well to note that nothing was attached to the outlet line of the regu lator at the time of the incident inasmuch as they were only checking to see if the regula tor was satisfactory.) CMA 015557A Cause: The causes of the accident w re: 1. inadvertent mishandling of explosives. 2. Drying explosives in glass beakers. m 3. Possibility of detonation from impact during handling while hot and dry. 4. Flaw in beaker from thermo effects. Preventive Measures: 1. All ovens shall be equipped with upper limit temperature control and grounded. 2. Drying lead styphnate for the purpose of determining the average granulation size weight will be accomplished by weighing in water using a pycnometer. 3. Handling of dry explosives will be eliminated whenever possible and use of glassware will be minimized. CASE HISTORY NO. 958 Possible Static Electricity Flashes Flammable Vapors Description: An employee was renewing the filter "heel" on the screen of a centrifuge. The old "heel" powder had been scraped off and the screen flushed with a vehicle. The fresh pas er was stored in a leverpak with a poly ethylene drum liner. Because the drum was nearly empty, the employee dumped the powder directly from the liner into the centrifuge. It was at this time that a flash occurred. T^kemployee received minor and moderate burns t*coth arms, face, ears, and neck. Two main tenance employees who were standing by to close up the centrifuge received moderate burns on their arms as they assisted the em ployee from the area. Cause: 1. High level of fumes inherent in pro cess . 2. Possible static charge created by powder flowing from the polyethylene bag. Preventive Measures: 1. Operator to wear aluminized jacket and hood with air supply. 2. Flushing with vehicle will be discon tinued. 3. A grounded aluminum scoop will be used to apply fresh powder. 4. Additional grounding of centrifuge to be provided. 5. Use of polyethylene drum liners will be discontinued. 6. Block valves to be installed on centri fuge to limit vehicle fumes. CASE HISTORY NO. 959 Ammonia - Leaking Control Valve Description: Employees were starting up a granulation operation after a four hour shut down. They were in the plant control room. As the granulator started rotating, liquid ammonia, which had leaked past th closed valves, vaporized rapidly, overtaxed the fume collecting system and billowed out. The doors at the discharge end of the granulator were open for observation, and the ammonia vapors flowed out and into the control room just as the employees were leaving to inspect the granulator product exit. The employees were forced to retreat and leave the room through an exit behind the control panel, which ex posed them again to heavy ammonia concentra tions. One employee was hospitalized. Cause: Ammonia which leaked p^st two closed manual block valves, and a closed automatic control valve, did not vaporize because it was trapped by crusted material or because the sparger nozzles were plugged. Also, the granulator fume collection duct and the duct entering the primary scrub ber were partially blocked. (Note: The vapors discharged so rapidly, employees did not have time to don pro tective masks and leave the control room which is in direct line with the granulator discharge. The door in front made it necessary for the em ployees to exit from the room via a door behind the control panel which opens alongside the granulator.) Preventive Measures: The leaking control valve has been repaired and the two block valves are being replaced. The granulator fume system will be cleaned regularly and the plant will not be operated unless there is sufficient draft on the fume collection system. Also, a spray has been installed in the duct enter ing the primary scrubber to prevent block age at this point. A door is being installed at one end of the control roam to provide another emergency exit. CASE HISTORY NO. 960 Explosion - Sight Glass Failure Description: Trying to repair a leaky sight glass on a vessel under pressure was the pri mary cause for a chemical plant explosion and fire that resulted in 7 deaths, 2 critical injuries and property damage exc eding $4 mil lion. The 85' x 85* building with drying and packaging area attached contained 20 - 2,000 gallon reactors used in the manufacture of polyvinyl chloride, (PVC). All electrical equipment was explosion-proof and the build ing was ventilated at 20 air changes an hour. One reactor had trouble with the 6 inch CMA 015558 sight glass which had a light above it. The lead and asbestos gasket and sight glass wer replaced and the vessel put on stream. The foreman noted that at 140F. and 140 p.s.i.g., the system was tight, but while the mainten ance men were in the building to repair a valve on another reactor, they were asked to check the sight glass. A small leak was ob served and a maintenance man tightened the nuts with an open end wrench (not a torque wrench). One the second round of tightening, a one inch ribbon stream of water and vinyl chloride suddenly shot out and knocked the man down. He was bleeding from the face and ex ported out of the building. Regular emergency procedures were started immediately, e.g., windows and doors were opened, steam to reac tor shut, additions stopped, and the manual vent to the reactor opened. An operator was overcome by vapors and carried out. Five minutes later a tremendous explosion occurred, ripping the building to pieces. The contents of 18 reactors were dumped but there was very little fire in the building. The explosion wrecked the sprink ler system and the Post Indicator Valve could not be reached. Pressure dropped to zero in critical locations. There evidently wasn't a sprinkler line loop on this area. A warehouse, laboratory and office building 150' x 800', was 60 feet south of the build ing. A wall was blown down, several small fires started and propagated along the roof. The roof caved in and the building burned several days, to complete destruction. The sprinkler pressure was zero in this area. The boiler and maintenance building 80 feet to the north, was extensively damaged and other surrounding buildings also were dam aged to varying degrees. Winders in homes were shattered and some homes evacuated. Of the dead, one was found in the dryer room attached to the building. Pour bodies wer found outside, between the building and the warehouse, indicating that conditions had changed from emergency to evacuation within a five minute period. One fatality occurred in the boiler room, 80 - 100 feet away. Cause: The investigators feel that the 6 inch sight glass shattered completely, causing a sudd n build-up of flammable vinyl vapors which found an unknown source of ignition. Possibly glass fragments broke the ceiling lights. CASE HISTORY NO. 961 Plugged Transfer Line Description: An operational difficulty, poor communications, and faulty judgment resulted in a steam burn and 2 days of lost time. A section of transfer line betwe n 4 stills be came plugged with tars and could not be un plugged with solvent or nitrogen. A cap ona :branch section of piping was removed and hd pressure steam connected. At the sections the line that were free, valves were set to permit condensate to bleed to the floor. The section leading in the other direction was plugged and valves to these stills opened wide. At shift change the outgoing supervisor in formed the incoming supervisor of the condi tions and explained in detail the positions of the valves on the transfer line, without direction from either supervisor, and with out notifying the supervisors, 'an incoming operator noticed the condensate coming from the end of a bonded hose and shut 3 valves on this system. The supervisor went to check about 10 minutes later, saw only drops of con densate coming from the bonded hose and opened a plug cock on this line to check steam condi tions. As soon as the condensate drained out, a sudden gush of steam caused the unsecured hose to whip and steam contacted his legs. He applied cold water and was transported to Plant Health. Preventive Measures: Use of high pressure steam for this purpose is very hazardous. A memo from the plant management has been issued, re-emphasizing to supervision that it should not be done. The operator obvious ly should not have touched the valves withq^fe finding out why the condensate was flowing The department head has instructed his super visors to transmit information on unusual con ditions or procedures by personally visiting the site. Flexible hose should not be per mitted to hang loose on any system that can be under pressure. Either detach it com pletely or secure it and direct it away from personnel. Plant management has re-emphasized this directive as well. FGS:cm 3/19/64 CMA 015559