Document oeRmdkbvDwQZxXD8v958qNXqr

March 25> 19^6 M r . T . K . A . Bevan, Associated Ethyl Company Limited, Artillery House, Artillery Bow, London S . V. 1, England.., . , Dear Ray; , . .... ' ;;: .' : , ' I should have preferred to cable my reply to your letter of March 18 in view of ,the shortness of time and the failure of your earlier letter to reach me. However, I belkve you will appreciate why this was inadvisable when you know my comments. I am forced to the belief that some of the people who have conferred with you fail to appreciate the very great difference between the serious hazards of handling sludge containing even minute quantities of tetraethyl lead, and the very small rela tive hazard Involved in exposure to the.dust derived from scale. The first of these hazards is of such a sort that fatal intoxi cation might result from fifteen minutes of exposure under the worst conditions that can be imagined. The second is of such an order of magnitude that fatal poisoning is not to be expected at all. Brief exposures to dust may cause discomfort, sneezing, coughing, irritation of the eyes, and stinging of the skin, and if prolonged,such exposure has been known to produce mild intoxica-tion derived from the absorption of trie thy 1 lead com pounds or other related decomposition products of tetraethyl lead. However, serious poisoning would not be expected to result in any ins tance than from prolonged exposure over a period of days or weeks. This is the important principle to be borne in mind in setting up regulations. Iurchermore the lead exposure of repairmen, welders, and the like, working in a tank that has been cleaned but not scaled or brushed is of a degree of severity com parable to that of lead burners, but perhaps even considerably less. What we are attempting to avoid here is unnecessary expo sure to lead compounds which if continued over considerable periods of time might veil result in lead accumulation in the body and eventually lead intoxication. Before suggesting the modifications that seem necessary to me I should like to comment on a few of the comments made at your meeting dated 21-2-^6. On.the first page of these comments marked therein,page 2 - Repair Operations - it has been suggested that a free air-line mask with hose length net exceeding 50 feet, and the self-contained PROTO-type mask should be included in this paragraph. With reference to the free mask you will note that our original booklet admitted the propriety of the use of these in connection with the cleaning of small tanks. There are a number of reasons why this is not safe in the case of the larger tanks. Mr. T. r.. A. Bevan - 2( ) - March 25* 19^6 Consequently I should he willing to reinstate the note appearing in the first regulations booklet, but I should not be willing to grant the use of the free air-line mask under other circumstances. There is very little question in my mind that the ful'l face-piece type of mask supplied with compressed air or oxygen by means of a cylinder Is entirely satisfactory. However, there are a number of difficulties in connection with the use of these that call for more or less expert or intelligent handling. For example, it must be ascertained that the air or oxygen pressure is maintained for as long as is necessary. Moreover, some refinery people have objected to the use of oxygen in connection with work around gasoline. I am.not competent to decide this point, but we are planning to carry out'observations with cylinders of compressed air so as to determine by practical experience the precautions necessary under conditions of practical use. The cylinder, as you will realize, has certain advantages over a pump, in that there is no possibility of contamination of the contents of the cylinder by reason of the contamination of the surrounding atmosphere. These comments do not apply precisely to the subject of repair operations but are meant to deal generally with the problem of positive pressure air-line masks. One realizes that these are not always available. On page 2 of the comments,criticism is offered to our willingness to let men wear merely overalls in scaling operations. This, of course, was deliberate on our part in that the use of gloves anc boots here is wholly unnecessary. There is no significant quantity of tetraethyl lead to be dealt with at this stage of the work, provided the sludge has been removed completely. Further down on page 2 of the comments, reference is made to the impossibility of there being dust as the result of brushing afcer cleaning and scaling of the tanks. This ignores the fact that any rust on the side of the tank contains traces of lead, and that such rust is not completely removed by ordinary scaling operations. The paragraph at the bottom of page 2 says that there should be no hazard due to tetraethyl lead on the outside surface of any tank or component. This statement fails to take into account the fact that the repairman is often working under conditions in which gasoline had leaked out of the tank into the surrounding soil and on the surface of the tank. Sometimes it is necessary to dig down to reach a leaking pipe. Under these circumstances the man may be working under conditions which are only slightly removed quantita tively from those which occur inside an uncleaned tank. On page 5 the same point has come up in the third paragraph from the bottom. Obviously the same situation exists there. In the second paragraph from the bottom of page > the question of H 00 0 7333 Mr . T . K. A. Be van - ( 5 ; - March 2 5 * 194 6 removal of scale from rail and road wagons has appeared to the critic as requiring the precautions in section 1 (Aj. Our deliberate opinion based on factual information is that there is no hazard here that is in any way comparable to that obtaining in storage tanks As has been indicated in the original booklet, the only hazard here is in connection with ocaling, brushing and repair operations which will give rise to dust if they are carried out within a dry tank. This again is a matter of a confusion of mind concerning the relative hazards of handling sludge and scale. How for my specific recommendations: - I am not very keen on the section entitled "Sources and Nature of the Hazard." However,, I do not object to it too much if it is not misleading. Frankly I do not consider it necessary, and I even doubt its wisdom, unless the hazards are discussed in sufficient detail to make them quite clear as to their character and degree. There is at least one sentence which is misleading. Line 7 and 8 should be changed to say "can cause serious and even fatal Illness." This could be said even more vigorously, but my point is the removal of the word "prolonged." Prolonged exposure is not required. "What is probably not appreciated here is the fact that fatalities have resulted from exposures for one to three or four hours, fatal poisoning can occur under the worst conditions from considerably less than one hour of exposure . Prolonged exposure as we use the ex pression in this country refers to days, weeks or months cf regularwork . Under section 1 (Bj,rule j? in my opinion is unnecessary, and because unnecessary is inadvisable. These regulations should be made as stringent as is necessary, but not one bit more. It is certainly unnecessary for men to wear air-line masks or canister masks, in removing scale from the sides of the tank that has been freed of sludge. The eyes should be protected by goggles, and if there is to be dust for any reason at all, an efficient dust respirator should be worn. .However, If the purposes of rule 5 are accomplished, there will be no dust, and under these circumstances goggles only are required . Overalls merely provide protection of the external clothing from contamination. They were, not intended nor are they required to protect men against absorption of tetraethyl lead, for there is no significant quantity of the latter present. Therefore, I should delete rule 5 and its explanatory note, replacing it with rule 5 and following this with a note as follows : "If for any reason the tank walls cannot be kept wet, efficient dust respirators must be worn continuously by all men who enter the tank during scaling operations. Delete rule 4 entirely and change rule 6 as follows, making It rule 4: "liust scale within the tank and after removal should be handled only In the wet state and burled to prevent its being disturbed or blown about." This rule is phrased so as to indicate that rust Beale is totally different In its poten tialities from that of sludge. One does not want it on the surface K E 0007334 Mr*. T. F;. A. Eevan - (4; - March 25# 1946 . of the ground where it may he blown about or in roadways or other places where it is likely to be agitated. Otherwise what becomes of it is relatively unimportant. Section 1 (Cj.I should advise the addition .of a rule 3, since :.i it is unlikely that it will be desirable to have any water in the tank at or near the 3ite of the welding. It can be argued that . this could be done in the wet state, and that the welding or cuttfr could be done later. However, that often turns out to be inconveni ent and time-consuming. Accordingly the brushing is likely to be done in a dry state. I am speaking here of comparatively small areas, and I recognize that it is quite unlikely that an entire tar would ever . be cleaned to the extent that is necessary for suita ble welding operations. Accordingly I should add rule 3 as follows "If brushing down to clean metal Is done without wetting the surfac of the metal, the workmen must wear efficient dust respirators. Dust suspended in the air of the tank by these operations must be ' removed or given time to settle out of the air before repairmen may be permitted to enter without respiratory equipment.Section 4 of the regulations, as applies to rail and road tank-wagons, is ; unnecessarily stringent. This regulation would be regarded as burdensome in this country. In my opinion the manner in which pre cautions were advised in the original booklet is far superior to . what is included here. These tanks do not contain sludge, and : therefore precautions are required only in connection with scaling and repair operations. In general this is probably equally true of barges, but we have seen some pretty dirty barges in this country, and certainly a few of them have been found with sludge in the ! bottom. Eo doubt a considerable number of barges has veen cleaned without any advice or help from our safety people, but the tendency is to take more precautions, and indeed to use precautions substan tially equivalent to those employed in cleaning gasoline storage tanks. For this reason I should be inclined to change section 4 to refer to barges only. I should then create a section 5 or 6, whichever you prefer, to deal with rail and road tank-wagons, saying in this section just what is said in the present section 5, which refers to ocean tankers. - Finally let me say in conclusion what you already know, ve are not in the need of any significant increase in the stringency of regulations. I think it is probably true that some of the things ve advised were not fully understood, and therefore your- efforts to eliminate any causes of misunderstanding are well taken. On the other hand, what we are in great need of is the precise application of the regulationsiwhether their background is fully understood or not,at >the point where a tank or other equipment is to be cleane If we can accomplish this, we will have achieved our purposes, sinc it has been clearly demonstrated in world-wide observations that where the regulations are fallpved there is no untoward result. We want to do everything ve can to make this as simple as possible of accomplishment, and this, of course, requires the understanding cooperation of the petroleum distributing industry. I trust, hov- / <^ .0007335 u iy / Mr . T . A, Bevan - (5) - March 23, 19^5 ^on,e of U3_will allow of doubt on the subject of the adequacy of the regulations as ve have promulgated them.' kindest personal regards to yourself and cordial greetings to my iriends and acquaintances on the Petroleum Board. gXeelln*>s t0 Sincerely yours, KAK ef ' Copy by air mail. Original by steamer. Bobert A. Kehoe, M. B. K" 0007336