Document v1B9zDKvowXL07Vk2Qn8rEa3m

249 Acute T richloroethylene Narcosis Accident Involving the L se of Trichloroethylene in a Confined Space !'. O LONGLFA, MB, BS \xn R. JOSES. Bit SVUNEV. AUSTRALIA Introduction At the factory in question, large tanks are entered periodically to resurface exposed metal joints with a bituminous paint applied with a brush. Each tank is porcelain lined, 9 feet in height and 15 feet long, and has 1 entry port 15X16 in. positioned 2 ft. 6 in. from ground level. They occupy most of the floor space of a poorly ventilated basement area, maintained at approximately 32 F. In order to dry out the tanks prior to painting, 4 infrared heaters are placed inside and switched on 16 hours prior to painting: they are left on during painting. Ehi the day of the accident, 2 experienced imnters, who had both carried out this work tor 8 years, commenced work at 8 a.m., one t^an entering the tank and painting for 30 aumites while the other remained outside. SuPmiued tor implication Tilly 2, 1%2. _ Senior Medical Officer (Dr. Lonjrfev), and 5ciemiiic Officer (Mr. Jones), Division of Occupa'Rwial Health, Xew South Wales Department of PuWic Health. Jm' Fach 30 minutes the men changed places. It was normal procedure for the painter inside the tank to wear an air-supply respirator at all times'. One air-supply respirator teas issued tor use by the inside man, and it was stated that the first employee to enter the tank used it for a short period. Air flushing equip ment attached to the top of the tank was not used, as this caused moisture from condensa tion on the surfaces to be painted. At about 9 a.m. the use of the air-supply respirator was discontinued, as the operator believed the air supply to be contaminated. Detailed tests of the supplied air on the day following the accident and on 2 subsequent days did not show any contamination. A fullface respirator fitted with an all-purpose canister suitable for organic vapors was sub stituted for the remainder of the work. At noon, the painter resting outside the tank observed that the man inside the tank was beconrng increasingly incoherent, with a staggering gait and the appearance of drunkenness. The former person ordered his o340V7 Sb 230 MAN HOLE ARC mi `ns of f.M'irosmf.xtai. in.,iriI. AIR SUPPLY SWITCHED OFF ..if TANK fellow worker to leave the tank and instructed him to get some fresh air. While the affected person walked about outside, the other man entered the tank "for a few minutes" to clean up prior to taking a meal break. It has not been established whether he put on a respira tor or not. Some time later the man outside the tank, ^having partially recovered, returned to the tank, looked inside, and saw his mate sprawled apparently unconscious on the bottom near an area of spilled paint. Immediately, without waiting to put on a respirator, he started to crawl through the manhole to rescue his friend. While halfway through the manhole, after taking only 1 or 2 breaths inside the tank, he fell forward unconscious head first into the vessel with his legs still protruding from the manhole. Fortunately for both men, these protruding legs were noticed by another worker at about 12.40 P.M.. and both men were removed from the tank by 12.55 p.m, Neither was wearing a respirator. Both regained consciousness before ar riving at the hospital but were somewhat con fused and disoriented for some time. The 2 men reported for work the next day and have lost no time since the accident. Investigations Officers of the New' South Wales Division of Occupational Health were called in the following day to investigate this accident w'hich so nearly resulted in a double tragedy. It was quickly established that the mo-t likely cause was vapor from the paint u-ed: The latter contained 75% trichloroethylene and had been thinned w'ith an equal amount of thinners containing 98% trichloroethylene. The materials stored in the tank were of a nontoxic nature. As the tank was a very confined space sit uated in a basement area which was poorly ventilated, the possibility of oxygen deficiency and carbon dioxide excess was also consid ered as contributing factors, as both men had complained of "air-hunger," Preliminary' tests were commenced 2J hours after the accident. At this stage the paint was dry, as was the area of paint spilled on the bottom of the tank. The 4 infrared heaters had been switched off after the acci dent. Trichloroethylene estimations ucre carried out with a Davis Halide Meter. In the center of the tank 2 ft. from the lh" ''. the trichloroethylene concentration w.t- 1-' ppm. To simulate the conditions resulting to an area of spilled paint, 3 shallow trayprepared paint were then placed on the !*' tom of the tank. After some minute-. ri`` trichloroethylene concentration had I'i-vii m more than 1.000 ppm beyond the range the Davis Halide Meter. I */ /, Vtos ACUTE TRlCHLOROLTUYlAiS On the same day at 8.30 iwi, |evel was found to be 19.5' < andioxide le\el 0.7%. The (rich level near the trays and the manh to 2,390 pptn by this time, as dete evacuated "grab" samples and tin method over platinum.1 Because these preliminary tes1 elusive, it was decided to duplic, 3s possible the conditions iusi leading up to and at the time of and then to carry out a further s< An exactly similar tank in the s. area was used for the final tests red heaters were switched on lb testing was begun. On this occa inside the tank began at 10.45 painters worked inside alternate minutes. At 12.50 p^r, 3 tray paint and thinners (approxim; were placed on the bottom of simulate spillage. Apart from th air-supply respirator was used tl painting, conditions approxima: as possible those leading up to Painting ceased at 1.20 r.n. (T Trichloroacetic acid cstimatu ried out on the urine of the 2 and on one other subject who to final investigation (Table 2). T stitute painter was detailed to work during the tests, as No. 1 pinter who first became uncoil? not to work in a confined space Protective Devic< In theory, the full-face resp all-purpose organic vapor can is should give adequate prutectioi Tabu: l.--R^uUs of 7 Trich ethyl in A Time Situation PP* IL15 a.v, 11 VM, i- m. >2 V, |. y 1 Hi f.M, 'aip.M. Center, bottom of tank " At manhole, inside tank ('enter, bottom of tank Far end of tank Id* 1.7 :u 3,2 l.onplt'x- Aniic< SL 034048 jiCLJTE TRICH LOROI'.TIIY LEX E NARCOSIS 251 On the same day at 8.30 i'.m. the oxygen jesel was found to he 19.50 and the carbon dioxide level 0.70c. The trichloroethylene level near the trays and the manhole had risen to 2,390 ppm by this time, as determined from evacuated "grab" samples and the combustion Atethod over platinum.1 Because these preliminary tests are incon clusive. it was decided to duplicate as closely as possible the conditions inside the tank leading up to and at the time of the accident and then to carry out a further series of tests. An exactly similar tank in the same confined area was used for the final tests. Four infra red heaters were switched on 16 hours before testing was begun. On this occasion painting inside the tank began at 10.45 a.m., and 2 painters worked inside alternate shifts of 30 minutes. At 12.50 p.m. 3 trays containing paint and thinners (approximately 1 pint) were placed on the bottom of the tank to simulate spillage. Apart from the fact that an air-supply respirator was used throughout the painting, conditions approximated as closely as possible those leading up to the accident. Fainting ceased at 1.20 r.M. (Table 1). Trichloroacetic acid estimations were car ried out on the urine of the 2 affected- men and on one other subject who took part in the final investigation (Table 2). The No. 3 sub stitute painter was detailed to carry out the work during the tests, as No. 1 subject (the painter who first became unconscious) elected nt to w ork in a confined space. Protective Devices In theory, the full-face respirator with an dl-purpose organic vapor canister attachment should give adequate protection for a period Tabi.k Results Tests Time Situation Trichloro* ethylene in Air, ppm . .A M Confer, bottom of rank 11 . ,SS A M pu 1-10 P.m, P.*, Ar manhole, inside tank Center, bottom of tank Far end of tank % Oxypen Nor done 20.5 Not done 20.5 Not done US /..Mi rj!'ey--J. in,- Tabi.k 2. --Trichluraci lie Acid hstimalums Days After Accident .Subject Trichloracetic Acid m I'rme, ME. per Liter ( \o. 1 1 No. 2 ? No. I f) ' \ \0, 2 ) No- > ` \ No. 2 I Xo. t 11 l No, 2 1 No. 3 (substitute M 37 * is? 37 75 4.5 2i.S 3.5 * Not obtained; on leave duo to back injury. of at least one-half hour in an atmosphere containing 1% trichloroethylene, at a rate of 16 liters per minute.3 The respirator was tested after the accident by passing trichloro ethylene at a concentration of 0.39c through the canister. Complete absorption occurred, indicating that the canister was still effective. In practice, its use could be attended by difficulty due to misting of the gogglesTmd restriction of head and neck movement in a confined space. Because of this, early intoxi cation of both operators may have occurred due either to the removal of the facepiece or to the fact that it was ill-fitting. An air-supply respirator should be worn to avoid such mishaps. Furthermore, as the use of protective equipment is subject to hu man error, respiratory protection should be regarded as a last resort, and every effort should be made to reduce the vapor concen tration from a toxic to a safe level by the use of nontoxic substitute solvents. Comment According to McCord (19321, the narcotic action of trichloroethylene appears at a con centration of about 10,000 ppm 4 L. T. Fairhall ( 1957) is less specific and states that severe narcosis is produced only by high con centrations and prolonged exposure.5 In this accident, both men suffered acute unconsciousness, following 2 hours of earlier exposure and mild intoxication, after which they reentered an atmosphere containing an estimated 3,000 ppm of trichloroethylene. In one instance unconsciousness occurred after -.--jS SL 034049 252 ARCiunis or i:\nRoxMi-.XT.u. working about 10 minutes: in the case of the liter 24 hours after the accident, and in ,,IV second employee unconsciousness apparently case the level had risen to 1X7 mg. per li[rr | occurred immediately as he entered the tank hours after the accident. This suggests a in the second occasion. Conclusions 1. Under certain conditions at least, the narcotic action of trichloroethylene can cause acute unconsciousness in concentrations much lower than the generally accepted level of 10,000 ppm,4 2. Acute unconsciousness can result from the inhalation of trichloroethylene in a con centration of 3,000 ppm if the subject has had an immediate earlier exposure resulting in a mild intoxication. 3. This could explain the almost instant unconsciousness which has occurred when degreasing tank operators have entered a tank for some purpose. 4. No prodromal symptoms were de scribed, so no warning is received by a sub ject that unconsciousness is imminent. 5. The accident described further under lines the necessity to wear a safety rope when entering a confined space. In this case, this precaution had been neglected, 6. Ahlmark and Frossman - have inti mated that a limit of tolerance of trichlor acetic acid in urine be fixed at 20 mg. per liter. They also state that effects occur in about half of the persons excreting40-75 mg. per liter and in almost all those excreting 100 mg. or more. Levels of trichloroacetic acid in urine have been observed by us, in subjects chronically exposed as high as 310 mg, per liter, and apart from some headache these subjects had no complaints. After un consciousness, urinary trichloroacetic acid levels of the 2 men were 55 and 37 mg. per gree of tolerance in those chronic,dh ,:X. posed. Summary Two cases of acute unconsciousness duL. v trichloroethylene at an estimated breath in. zone concentration of 3,000 parts per mil|:,,r are described. This concentration is ently lower than previously quoted h-im- Two painters working inside a large tan's and using paint containing trichlorueth; h-p,solvent, were found unconscious. I loth Lcame mildly intoxicated during their tiro a hours of work and had left the tank to renner in the fresh air. Reentry into the tank u,ts followed by acute unconsciousness, in one case almost instantaneous. We wish to thank Dr. E. S. A. Meyers, 1 )nv. t. r of State Health Sendees, for permission to pul-ii-I: this article. R. Jones, B.Sc_, Division of Occupational Health. X.S.W. Department of Public Health, Box .!!. George Street Nth. P.O., Sydney, Australia. REFERENCES 1. Olsen, f. C.; Smyth, H. S.; Ferguson, < 1 F.. and Scheflan, L.: Quantitative Determination of th< Concentration of Vaporized Carbon Tetrachloride, Indnstr. Eng. Cliem. (Anal. Ed.) 8:260, 1936 2. Ahlmark. A., and Forsman, S.: Ev.dnatirz Trichloroethylene Exposure by Urinalysc- t> ' Trichloroacetic Acid, A.M.A. Arch. Industr. Hc.ii't: 3:386, 1951. 3. Standards Association of Australia Specifica tions A.S. No. Z18. 4. McCord, C. P.: Toxicology of Trichloro ethylene, I.A.M.A. 99:409, 1932, 5. Fairhall. L. T.: Industrial Toxicology. I .d. - Baltimore. The Williams & Wilkins Company. 'l]''. p. 349. t Respiratory Chlorinatec Introduction i Cotton is the main harvest ing the summer months, inset, all over the country to con worm. Various degrees of re tion have been observed as a sive exposure to different i rotenone, nicotine, Lethanes tetrachlorodiphenylethone (T and the organic phosphates, phosphate (TEFP) and O, nitrophenyl thiophosphate (I1 The purpose of this paper cases of acute bronchiolitis w shadows following heavy ex; rinated camphene sprays. To this is the first time such le reported in agricultural work this chemical. Report of Cast Cask 1.--A 43-year-old whit himself with a chief complaint of onset associated with vague pain nary region. He also compl: fatiguability for the last 2 month was heavily exposed to chloi `pray In the previous 4 years h other insecticides. The patient dr any important chest disease betc finding 0f a_<;thma or allergy in family history. Physical examination Aug. 19 well-developed, well-nourished i 0324050 Submitted for publication Jmv Assistant Professor of CheShams University. !.:6 UT