Document 3ekBq4mXO2Q8dbeBd4oQkgkdO

KORSAKTO CHEMICAL COMPANY location Texa3 City, Texas Date August 15, 1963 Subject MERCURIC SALT EXPOSURE To V, R. Hisbefc cc; Plant Manager's Safety Board Carl H. Duhon J, ltf* Kongafcle For the past several months, VCM operating and maintenance super vision with, the assistance of the safety department have studied the exposure of personnel to mercuric salts in the handling of catalyst and maintenance of reactors in VCM, This study was triggered by an incident which occurred in lat-s Kerch and was ex tended to Include the tubing operation, of two VCM reactors in April and July of this year. On Kerch 26, 1963, a VOM reactor (22R1-4) was shut down at 0400 to replace a leaking top head gasket. Nitrogen was used to purge out the organics while steam was kept on the shell side to keep the reactor hot. Later the steam was stopped, and the reactor cooled down to 44C., preparatory to performance of the required work on daylight hours (March 28), However, it was felt there was still too much HCi and organics on the bed, so purging and stealing were resumed. At Q^KX), March 28, the steam was again shut cfxl and the work was performed on the morning of March 29. The temperature of the reaofcor shell was estimated to be about 72CC. ar, the time the work was done. The top head was removed, t-13 old gasket removed, a new gasket placed, and the head returned oni bolted on. This was done by four boilermakers, requiring about U5 - 60 minutes during which time these men were exposed. No ^enlelation other than, natural air currents was provided. A?.so on Kerch 28, the- same four boilermakers were involved in the re-al of port I one of the- catalyst screen on 22R1-5- Two of these u.3:i; Lucas and Hawkins, performed the burning work of removing the sure an sections. They were occupied in this job almost continuously curing the four afternoon hours. The other two boilermakers worked off and on in she ''io.inity of this particular job. The cutting of the screen involves the use of a torch to out the screen, dlreecly celcv: the bo ..torn tube sheet. i\ section of tubes adjacent zo the joint of cutting had been emptied of catalyst. It is impossible to can .he screen without trrnsfu =.rii-g, some heat to the tube sheet and r-.-aev.-:- tubes full of catalyst nearby. It could nc-t be determined which Incident or if both incidents constituted the exposure.- of these employees. CBY 1017893 RSV0031920 W R. Klsbefc Page 2. i^te Pvid&y afternoon, Lucas noticed that he had a measle-like rash on his lowez* legs. By Monday morning, April 1, whan he reported, to the dispensary, he was badly welted around his neck, arm pits, waist, lovjer body and legs. He wa3 referred to our doctor who, upon learning of the suspected exposure, obtained a urine specimen from the patient and treated his skin eruptions. By Tuesday morning, he reported directly to the doctor because by now he had considerable swelling around the eyes and in the legs. The swelling, upon treat ment, quickly subsided and he returned to work. On Thursday, April 4, the specimen result was reported at 214 micrograms of mercury per liter of sample (normal is 80). An investiga tion was immediately begun, and the following steps were agreed to be taken*. 1. Safety department will find if a mercuric chloride detector is available (ordei'ed on April 7 and received on May 3). Each handling of the catalyst bed will be tested during the work. This will continue until the safety department 13 knowledgeable of the extent of the hazard and is satisfied wirh the control of that hazard, 2'. Operations will immediately revise the written operating instructions to require that the reactor be cooled to ambient temperature before maintenance personnel will be permitted to work on the reactor. 3. Maintenance will immediately remove the boilermaker with the rash from the area. In addition, the other three boilermakers will be informed of the situation and specimens taker.. 4. Depending on the results of the various tests, a rotation plan for maintenance iiorkers in this particular area will be considered. On Tuesday, April 9, the results of the other three boilermakers were obtained and found to be In excess of normal. Each man was informed Individually by the Safety Director* Also, two other men were then samp let.--or.e was the VCM porter (l*Jii liams) who for many years has handled catalyst and probably has been exposed to the c'uot yore char, ar.y one other individual (he was found to be normal) , the other wan (t-tapes) was s. boilermaker who had worked every cotalysr-handli.ig .jod In the reactor section for the past year and t half and has worked in the are a five of the last seven years but did not work the specific jobs described herein (he was found to be normal). Io ic interesting to note that of the four boilermakers, Hawkins, vno exhibited toe highest level, was new to the reactor area having beer, assigned to that area on March 27, only one day before the ircidents de scr jl Os d * CBY 1017894 RSV0031921 W. R. Nlsbet A^ Page 3* On the basis of the results, Lucas (on April 1, 1963) and Jensen and Hawkins (on April 8, 1963) were removed from, this area. Uptmor was left in the area. Samples were taken approximately one week, one month and two months later and the results, although not con clusive, would indicate that all were normal and the exposure was minimal. The results of these tests are shown in Table I. The doubt arises from the erratic results obtained. The Complete Clinical Laboratories of Dallas, who performed the analytical work, suggested the use of new containers for each sample, and thlB was done after June 15. Discussions of the medical evaluation of the problem and individuals with Dr. Katlage and Mr. Garrett would lead to the conclusion that all four men had experienced only a minimal exposure, that the re moval of the men from the area was unnecessary, and that there would be no permanent effects as a result of this exposure. The real gain afforded by this Incident was the re-evaluation of the potential hazard and -the review and revision of work procedures. Certain environmental tests were made by safety department personnel using a Kitagawa Gas Dateetor. No mercury vapor via3 found during the loading of 22R1-3 on May 9, 1963. or on the unheaded but cata lyst full 22R1-5 on May 10, 1963. When 22R1-5 was empty and the tubes were being drilled out of the top tube sheet in preparation for the cutting of the tubes on June 18, tests indicated a maximum allowable coo centration, of mercury directly on. the tube sheet but no mercury at five feet above the tube sheet. Results are compiled In Table II. In April X$S3, a VCM reactor, 22R1-6, was retubed. The old tubes were removed by cutting "windows" in the reactor shell, placing a scan ins5.de the shell to Cut by torch a three-foot section of each tube so that the bottom tube sheet could be dropped, and then drill out from the top the remaining section of each tube. This work was performed by several crews on a continuous basis from April 11 thru April 19. The men were ventilated with fans sucking air away from the work, and the cutter was equipped with an air-ventilated welder's helmet. Two of the boilermakers, Moore and Q-uss, knowing of the other exposure, requested that they be tested for mercury. This was done on April 17, and the results indicated a minimal exposure (146 and 147' mcg/liter respectively). -- After this job was completed, the work method was discussed with the two man. One method for an exposure to occur was recognised from the discussion. The man while performing the cutting of the tubes had the ventilated helmet in place but would flip up the mask to see vihat he had cut. This left him exposed inside the reactor shell without the benefit- of the mask air circulation. In July 1963, another reactor, 22R1-5, was retubed. The two boiler makers requested that they be assigned to this job and cheeked for CBY 1017895 RSV0031922 VI. E. Nisbefc Page 4 mercury exposure. This was done, and in addition two other boiler makers, Jolly and Land, were also checked. All members of the crew were instructed on keeping the ventilated helmet In place during their work inside the shell. The results of their specimen mercury checks are attached in Table III. The elevation was slight but not above the normal maximum, of 80 mcg/l., and no health hazard due to mercury exposure was sustained by the men. To provide reference to understand the results of the urine mercury checks, 0 - 80 mierograms per liter is considered normal] above 80 meg/1. would indicate an exposure. An instantaneous exposure resulting in a concentration, of more than 80 but less than 300 meg/1, would be considered a minimal exposure requiring the removal of the individual from the area if the exposure was still present] above 300 meg/1, would be considered a definite exposure requiring the removal of the individual from any contact with mercury for thz^ee months or until mercury content drops below 80 mcg/i. Pro longed exposures causing the level to remain above 300 iacg/1. for a long period of time could result in serious health problems and disability. Such occurrences are extremely rare in American, industry. During the second reactor (22R1-5) retubing operation, environmental mercury checks were made by safety department personnel using a Drager Gas Detector. This instrument is capable of measurements in excess of the HAG of 0.1 mcg/ra^, the maximum of the Kitagawa Gas Detector. In orepar&tion for- the removal of the reactor tubes, the reactor was*unheaded, emptied of catalyst, and the tubes washed and rattled. There were 15" x 20" window's cut in the reactor shell on the north east and southwest corners and a 4800 afm. 6" venturi blower was installed to suck out air through the southwest window'. Data is compiled in Table T'T. The highest, concentration wa3 experienced while using the Outrode (3/lo" rod) and more smoke was visible, both inside and issuing out the bottom and top of the reactor, when this cutting rod was used. It is the opinion of the safety department that the hazard of mer cury poisoning in the V035 reactor area is minimal but varied de pending on the operation involved. 1. normal personal hygiene would eliminate any hazard from mercury absorption through, the skin. 2. Hashing uhe hands end face before eating or smoking is desirable to avoid catalyst ingestion by mouth. 3. The greatest- exposure is by oral inhalation of mercury vapors, and these can be avoided entirely or redueed to a r.on-hacardous level by adequate fresh air ventilation of the worker and the elimination of the exposure to CBY 1017896 RSV0031923 W. R. Uisbet: Page 5 catalyst above ambient temperature. Although no maximum safe bed temperature can be specified, the atmosphere above a 100F. bed is considered non-hazardous and work can be performed safely at bed temperatures in excess of this If adequate personal ventilation Is provided. 4. It is recommended that during heating or cutting opera tions involving an open reactor, whether filled with catalyst or not, only necessary work be done in the vicinity of the reactor and the area above and beneath the reactor being worked on be roped off. 5. When reactor re tubing is to be performed, "rattling" of the emptied and washed tubes reduces the exposure significantly and laekes the job cleaner and easier. /bs Attachments - 3 C. L. Gilmore CBY 1017B97 RSY0031924