Document 3J1KR88rZV2D9O7a2XwaazQdy

T H E A SSO C I A T ED E T H Y L CO M PAN Y, L I M I T E D LO N D O N V' M EM O RAN D U M ONTHE WHICH HAVE COMEIN CONTACT V WITH'/- TETRAETH YL LEAD , " ETH YL" AN T I -K N O CK CO M PO U N D S OR SO L U T I O N S O F T H E SE P R O D U C T S 0019598 ,- - . V THEASSOCIATEDETHYLCOMPANYLIMITED, LONDON M emorandum on the Decontamination of M aterials which have come in contact with Tetraethyl Lead, "ETH YL'' Anti-Knock Compounds or Solutions o f these Products INTRODUCTION t h e d i spo sa l of spilled tetraethyl lead or " Eth yl" anti-knock com pound is a serious problem which involves im mediate hazard to those who undertake the task o f disposal, and to others who m ay be near at hand. Th ere is also the hazard o f later exposure to either interm ediate or end products o f the reactions of decontaminants on tetraethyl lead ( T .E .L .) T h e first consideration when T .E .L . or "Eth yl" anti-knock compound is spilled, is the protection o f all who m ay be exposed to it. T h e area m ust be evacuated by all except adequately protected persons until all danger has been rem oved. I n warm weather the hazard o f prolonged exposure (hours) to vapours rising from spilled m aterial m ay be considerable even at some distance from the area. (U ndiluted air saturated with T .E .L . vapour in tem perate weather, when breathed for ten m inutes, m ay cause fatal poisoning, and when such saturated air is diluted fifty-fold it m ay still cause illness i f breathed for an hour.) T h e help o f policem en and/ or firem en m ay be sought to ensure that all persons are excluded from the contam inated area. All persons whose duties require them to rem ain in the area m ust be protected against inhalation o f vapour by the use o f airline m asks, self-contained oxygen m asks, or m asks equipped with canisters containing activated charcoal. Protective clothing in the form of im per vious boots and gloves m ust be em ployed to prevent absorption through the skin. T h e second point requiring careful, but prom pt, consideration and action is i the lim itation of the spillage to the least possible area. I f a large spillage should occur in a populated area, it m ight conceivably be necessary-- for the immediate protection o f the public-- to rem ove it quick ly by flushing into a sewer. T h is should not be done unless absolutely necessary, since the contamination o f sewers and sewage disposal plants will inevitably result, and decontamination thereof m ay be difficult. I n general, attem pts to wash away spilled m aterial are ill-advised unless the quantity involved is so sm all that by sufficient dilution all danger of exposure thereto w ill have been eliminated. T h e third and final step is to decontam inate the area. I t is the object of this m em orandum to sum m arize the available knowledge on tins subject, and to suggest the measures which should be adopted under the various conditions which m ay be experienced. 2 G E N E R A L C O N SI D ER A T I O N S D econtam ination is the rapid conversion of T .E .L . to other lead compounds which are less dangerous and m ore readily elim inated. T h e conversion o f this liquid lead com pound to a solid reduces its capacity to vaporize, eliminates its ability to penetrate the skin, and renders it m ore or less soluble in water, thus allowing it to be diluted to harm less levels o f concentration. Such conversion can be accom plished by chem ical means and by burning. T h e incom plete conversion o f T .E .L . to interm ediate or gan ic lead com pounds, greatly reduces the hazards o f inhalation o f vapour and o f absorption through the skin, but these interm ediate lead com pounds m ust be handled with care as, in addition to their acting as an irritant to the skin, they will, under suitable conditions, react to produce T .E .L ., thereby recreating the original hazard. For this reason, the job o f decontamination is not com pleted until all T .E .L . has been converted to inorganic lead salts. T h is purpose is norm ally accom plished by providing such an excess o f decontaminant that complete conversion is assured. I t is advisable to ensure that the m aterial will not be dis turbed (e.g. b y excavation) for some years to come. I t is advisable to erect a sign m arking such an area warning possible excavators. Pits into which partially decontaminated m aterials are placed for burial should be lined heavily on all sides and above and below with chloride of hm e in order to prevent spreading o f T .E .L . Every effort m ust be m ade to secure com plete decomposition of all organic lead com pounds. * 3 d ec o n t a m in a t in g a g en t s T h e decontaminating agents which are con sidered suitable for use i n the field are listed in Table I . T h e choice o f these decontaminants was m ade from the standpoint o f efficacy in decontamination, commercial availability, and ease o f handling. TABLE I D ECO N TAM IN ATIN G AGEN TS D econtaminating Agen t Chem ical Form ula Solven t Concentration of Rela t ive D econtaminant Rate of Volumeper cent D econtamination Potassium permanganate Sulphuryl chloride Calcium hypochloritef ; KM nOt SO jCfs CaO Cl. W at er K er osen e W at er , 5* 10 Slur ry Rapid Fairly rapid Sl o w * T h e crystals o f potassium permanganate m ay be sprinkled upon a contamioated area, after which water can be sprayed on (a 5 per cent solution being approxim ately a saturated one), f Also known as chloride o f lim e or bleaching powder. N .B . I t must be em phasized that, with the exception o f potassium permanganate, undiluted reagents must never be applied to spilled materials as this would lead to explosive reactions a nd resultant fir e. 1. P O T A SSI U M P E R M A N G A N A T E a strong oxidizing agent, is an odourless salt o f a dark purple colour. I t s use b y the methodsindicated above does not entail any hazard. T h e solution o f the salt, however, will stain the hands and clothing, whilst a finely divided spray, i f inhaled, m ay result in toxic absorption. 2. C A L C I U M H YP O CH L O R I T E is a white or greyish-white powder smelling strongly o f chlorine. T h i s product ordinarily contains about 35 per cent o f available chlorine (the active ingredient) which reacts with T . E . L . to form non-volatile lead salts. D r y calcium hypochlorite reacts viol ently with T . E . L . and, therefore, m ust always be added in the form o f a wet paste or slurry. N O T E : Calcium hypochlorite readily gives up its chlorine when exposed to air or moisture. For this reason it should be kept in an air-tight con * tainer untilju st before use. Calcium hypochlorite should always be handled with care, fo r chlorine gas is toxic and also corrosive to most metals and cot t on fa br ics. 3. SU L P H U R Y L C H L O R I D E is a colourless, pungent liquid which is slowly decomposed b y water into sulphuric and hydrochloric acid. Caution should be observed i n its use as it i s both toxic and corrosive. Goggles and rubber gloves should be worn when handling the material; inhalation o f the vapours should be avoided, and adequate ventilation should be provided. Sulphuryl chloride liberates chlorine which reacts with T . E . L . to form non-volatile salts. T h e reaction can be accelerated b y the addition o f pyridine. 4 PREPARATI O N O F D ECO N TAM I N ATI N G M I X TU RES 1, P O T A SSI U M P E R M A N G A N A T E 3. SU L P H U R Y L C H L O R I D E A 5 per cent solution ( 0 * 4 lb. per gallon) Prepare 5 per cent or 10 per cent solutions o f is roughly a saturated one. I t is prepared sulphuryl chloride in kerosene. T h e m ixing is b y shaking an excess o f potassium per manganate crystals with water until no more will dissolve. T h e resultant liquid is then ready for use. done i n the open air, using goggles to protect the eyes, and heavy rubber or acid-proof gloves to protect the hands. T h e solution should always be m ade up fresh as it deter I 2. C A L C I U M H Y P O C H L O R I T E T h i s decontaminant m ust be used as a iorates rapidly during storage. Sulphuryl chloride solution is decomposed 1 slurry. I t is prepared b y m ixing equal parts of calcium hypochlorite and water (the best b y sunlight and, therefore, should be stored in dark-coloured botdes. O wing to the formation means o f m ak ing a smooth slurry is first to m ix a part o f the water with all o f the calcium o f gas during storage the solution should be hypochlorite, work ing the m ixture to a paste, lightly stoppered with a lead stopper, and then adding the remainder o f the water while stored in a well ventilated place where its thoroughly stirring the m ixture). vapours will not corrode nearby equipment. M AT ER I AL REQ U I R EM EN T S IN D ECO N TAM I N ATI O N t a b l e II MINIMUM q u a n t it y o f d e c o n t a min a n t r e q u ir e d f o r DESTRUCTION OF ONEPOUND OF T.E.L. D econtaminant U n dilu t ed decont am inant , pounds Pr epa r ed m ixt ur e, gallons Potassium permanganate Calcium hypochlorite Sulphuryl chloride 2 2 4 5 6 : I t must be stressed that the amounts listed are minimum quantitiesand several times these quan tities should be used during decontamination operations. D ECO N TAM I N ATI O N BY BU RN I N G T h e sim plest and perhaps m ost effective decontamination i s fire. W h en the contaminated object is o f little value it is best to destroy the article b y burning directly on an open fire. T . E . L . and " Et h yl " anti-k nock compound should never be burned without dilution with kerosene, otherwise a violent reaction m ay result. [I t is recommended that a safe burning m ixture is 10 per cent T . E . L . in kerosene.] Several pre cautions should be observed when burning a contaminated article or diluted " Et h yl " anti knock compound. I . Burning should be carried out in the open air as far away as possible from buildings and persons, so that no hazard is created by the sm ok e. 2. D iluted fluid or sludge should be binned i n a container which is wide open to the air, and i n wh ich the material is in actual contact with the flame. 3. T h e operator should work on the upwind side o fdie fire. 4. T h e fire should be kept burning briskly so that the T . E . L . will be consumed, and not m erely evaporated, b y the fire. 5 D E CONT AM IN ATIN G PRO CED U RES 1. D E C O N T A M I N A T I O N O F SO I L spilled material m ay be absorbed with rags, I f a large quantity o f T . E . L . (greater than i gallon) has been spilled on the ground, it m ay sand, soil, sawdust, etc., and removed to an isolated spot, m ixed with kerosene, and be wise to remove as m uch as possible o f the spilled material before applying a decon taminant. T h e following procedure is recom burned. After the bulk o f the spilled material has been rem oved, the contaminated area o f con m en ded: (i) Flush the contaminated area with a gen erous amount o f kerosene in such a man ner as to dilute the spilled material and drain it into a trench. T h e kerosene which crete is treated with generous amounts o f potassium permanganate. About two hours after this treatment, the area is thoroughly hosed with water. I f i t is advisable to remove the stain left b y the potassium permanganate, has accumulated is rem oved to an iso lated pit and burned. T h e kerosene flushing is repeated and the drainage dis this can be done with hydrochloric acid and generous flushing with water. I f the decontaminating operations did not posed o f as before. Again flush the area fully remove the lead hazard, the entire pro with keroseneand burn. cedure isrepeated. O wing to the porousnature (ii) Aft er the kerosene treatment the area is treated generously with potassium per o f concrete, absolute decontamination m ay not be possible. Should this be the case, it m ay m an gan at e. be necessary to replace the contaminated (iii) Finally, a slurry o f chloride of lim e is con cr et e. spread on the area and m ixed with the soil by raking, after which sufficient chloride o f lime is added to form a -in ch layer on top of the ground. I f the lead hazard persists the decontamination operation m ust be repeated. 2. D E C O N T A M I N A T I O N O F C O N C R E T E 3. D E C O N T A M I N A T I O N O F W O O D I f a large area o f wood has been contamin ated for any considerable period o f time, the wood cannot be decontaminated and m ust be burned. W hen the Quantity spilled is small or prevented b y reason o f an intervening coat of paint from penetrating the wood, decon T . E . L ., when spilled on concrete, will r e- ' tamination m ay be effected as follows: quire handling in one, or a combination, o f the following procedures: (a) W hen there is no opportunity or need for (a) T h e bulk o f the spilled material is absorbed using sawdust and/ or rags which are then burned. reclaiming or rem oving spilled material the (b) Aft er the bulk o f the spilled fluid has been contaminated area should be blanketed with potassium petm ^ gan ate b y applying crystals and a water spray, or an aqueous solution in great excess. (b) An y material ijvhich has collected in deep pools, together with any kerosene or gasoline employed to wash off contaminated surfaces should be put into standard drums. (e) Spilled material m ay be flushed to a con venient sum p or pit from which it is rem oved and put into drum s to be disposed o f by bu r n i n g. (a1) I n order to avoid its further spread, rem oved, the contaminated area is scrubbed wit h a slurry o f chloride o f lime, the slurry being allowed to remain on the surface. (U se potassium permanganate i f the resultant stain is o f no im portance.) (c) Aft er several hoursthe slurry (or the potas sium permanganate) is hosed off with water and scrubbed with soap or other detergent. (d) I f, after! this process, the hazard has not been eliminated, the decontamination pro cedure is repeated, and i f the second applica tion fails, the contaminated wood m ust be rem oved and burned. 6 4. D E C O N T A M I N A T I O N O F T O O L S, FI T T I N GS AN D M ET AL EQ U I PM EN T Fou r methods o f decontamination are r ecom m en ded: (a) Sm ooth all-m etal articles can be cleaned by repeated immersion in clean kerosene. |&) T h e contaminated article, i f greasy, should first be washed in kerosene. I f rusty, the article should be im m ersed i n 20 per cent hydrochloric acid containing o x per cent Sharpies 114 3 Pick ling I nhibitor until the rust film is substantially rem oved, then rinsed in water. D econtam ination can then be effected by prolonged immersion in potassium permanganate solution. (c) Aft er an initial rinsing in kerosene the contaminated article m ay be soaked in sulphuryl bhloride solution for several hours, followed b y a water rinse. N .B . This m ethodisnotto beem ployed i f the article may be injured by corrosion. (d) Articles which will not be unduly injured thereby m ay be decontaminated by fire. g. D E C O N T A M I N A T I O N O F PRO TECT I V E EQ U I PM EN T T h e methods prescribed in various form al regulations should be followed so far as pos sible. I f kerosene is not available or desirable, decontamination can be effected b y means o f a slurry o f calcium hypochlorite, followed by generous use o f water. CO N C L U SI O N D econtam ination in the field is usually accom plished with great difficulty, due to the m any dependent factors, e.g. tem perature, tim e, proper m ixing o f con tam inant and decontam inant, and porosity o f the surface on which T .E .L . has been spilled. Particular note should be taken o f the latter two factors; it is essential that good m ixing o f the decontam inating agent and T .E .L . be effected. W hen a spillage occurs on solid porous surfaces, e.g. wood and concrete, T .E .L . readily penetrates the pores o f these m aterials, and decontamination sometimes results m erely in destroying the T .E .L . near the surface. T h e products of the reaction tend to seal the still unreacted T .E .L . in the m aterials. For this reason it is essential that decontam ination be effected as soon as possible. O wing to the possible re-form ation o f T .E .L . by rearrangem ent o fthe lead salts form ed in the decontamination reaction, all areas which have been decontaminated should be revisited and inspected for possible Recurrence of a lead hazard. 7