Document YrLwND6pNeOy35GbewV4nREBn

I I VOL. 3, NO. 3 MICHIGAN DEPARTMENT OF HEALTH Albert E. Heustis. M.D.. Commissioner SPRING, 19 Construction Health Hazards Technological advancements along with new chemical products have created a new set of health hazard control problems in the construction industry. And these problems seem to be more severe in the construction field which does not have either the site or personnel permanency of the manufacturing plant. Instead, the construction industry is characterized by mobility; pick-up work crews; foremen who have little or Jrxa knowledge of the inherent hazards msorae of the materials being handled by their men; difficult working con ditions where weather is a significant problem: and a prevailing attitude that the generally rugged workers in the construction industry are not subject to health hazards. We have selected a group of topics for consideration which we consider timely, varied, and potential sources of health problems for construction workers. AH of them have been dealt with at one time or another by personnel of the Division of Occupational Health. Every year, either by request or through its own initiative, the Division checks out and advises on many con struction jobs. This is an extremely important function since more than 100.000 Michigan people work in construc tion and these workers daily face hazards which can be detrimental to their health. These hazards can.be injurious to health cither through acute or long exposurcTTh'cTm'mcdiate'asiHma-' tic effects of a single toiuune dilscyanate exposure or the pulmonary dif ficulties experienced by *an asbestos insulation worker after 15 years on the job can both be serious health problems. Also, when considered in the light of lost time by workers which Fiqur* ]. View of three workers on on osbostot iprevutq job. The worker at the Moor {* feeds- the marenai. Thc-wareer or the uepor lft tomes the turfoce. Note tbof oil thro* -exposed to oicessivo OMontimfr-of-asbestos-dusr and tl*af-fhetr- mptroran-ar*--nor~bcmq--woi can. mean severe economic loss to jhetr families as well us to the em ployer, the problems become more important and more complicated. * In this publication, we will deal with four rather divergent types of construction techniques which present varying degrees of hazards to wor ers. They include: (l) application epoxy-terrazzo floors and epoxy coi ings; (2) spraying of asbestos: (J application of red lead paint: at (4) pouring in place or application polyurethane foam. Epoxy-Terroxxo Ffoors & Epoxy Coatings Principal health problems associated with the application of epoxy resin base materials such as adhesives, paints, special surfacing mortars, and epoxy-terrazzo floors are dermatitis from skin contact with the amines in the mix. excessive exposure to toxic solvents used in some of' the resin systems, and. in general, nose. eye. and throat irritation caused by the amine catalyst and the solvents. Com pletely cured epoxy resins are not believed to present such hazards. Epoxy resin materials can be so formulated (by literally tailoring the molecules) that a wide range of de sired properties can be obtained. Some adhesivez can be made to present varying curing properties and unusual tensile strength. Surfacing compounds can be made impervious to almost all types of solvents. Paints can be made which are adaptable to conventional production spraying and baking oper ations in industry hut which present unusual surface protection properties. And epoxy-terrazzo floors can be co mplied which are essentially non-shrink ing. are impervious to most solvents, present a wide range of colors, are considerably lighter than comparable concrete type terrazzo floors, and have excellent strength characteristics. While the relatively high cost of many epoxy products has limited their general application in the building trades, their exceptional properties have resulted In a ra pidly increased use in the building and construction industry for spe cialty applications. These include long-wearing paints with special finish effects on concrete block wait surfaces, epoxy terrazzo floors which have exceptional wear re sistant properties, and special sur face coating (paving application) on highways. The new International Bridge in Sault Ste. Marie has a thin layer of an epory water-re sistant coating material between a concrete base and the top asphalt roadway surface. Purpose is to keep water from coming into contact with the concrete. Base material in manufacturing epoxy resin is ethylene glycol which is reacted with various types of amines to form a liquid pre-polymer. A wide variety of particulate type fillers such as synthetic fibers, sand, metai powder, carbon black, and weed dust arc used to effect certain properties and pearance and polymerization of pre-polymer is brought about with addition of diethyienediamine or ot complex polyamines (catalysts). Rate of polymerization or cur can be varied by chemical formulat and the application of heat may may not be required. During pc merization. various toxic amines emitted and. these can cause sev dermatitis or eye damage on cont or lung irritation if inhaied. Susce-. ble individuals can develop sensitiN to several of the amines used. In the epoxy-terrazzo floor plication, marble chips are imb * ded to form a unique terrx surface. The substance has the pearance of conventional cem terrazzo but is applied to a thi Figure 2. Material* uied n application*o< eooiv-terrosso floors and epoxy coonngx be dangcroux if allowed to come mro contact fh rtie sxm. Fltase note the lack or : protection ot the reim mixiAq-operotien. 1 'v./a i: JsL " w; Figure 3. Three workmen ore ihown troweling out 0 newly-poured cpoxy-terrasxo floor. You will notice that the workman in the center u imokmg o cigarette. * ness of" only *3/16 of an inch. xylene concentration was reduced to This epoxy-terrazzo can be applied about **0 parts per million where it directly over dry -concrete or wood, remained until the next xylene ap both of which have to be properly prepared to receive the surfacing material. Some of the adhesive or primer . coats contain solvents such as xylene and toluene indicating the need for proper control. A mixture-of marble chips and epoxy resin is then applied to the floor and troweled to a level of approximately 3/16 of an inch. This is followed by application of a heavy layer of marble chips which is spread uniformly over the entire floor and set in place with a roller. After several days of curing, the floor is then wet-ground with water in a conventional manner. It has been reported to this Division that der matitis is a common ailment among epoxy-terrazzo floor applicators ap parently caused by the amine catalyst. But this has not been evident in the two studies conducted to date. Ar rangements were made with a local manufacturer of flooring material to conduct occupational health studies Vt-'-two jobs which were scheduled since we were interested in both the amine concentrations which developed during application of the flooring ma terial and the xylenq concentrations which built up as a resuit of release from the primer coat and the trowel ing operations. Use of xylene is nec essary to ease troweling and surface rolling and to minimize adherence of the tools to the uncured resin mixture. In one recent study of the appli cation of a conductive surface type terrazzo floor in a surgery suite, no sienificant concentrations of amines were found in the immediate work area (ranced from O.i to 0.3 parts per miiUbni, perhaps because of the marginal type ventilation provided in the room. It did not appear that any of the workers had dermatitis and no reports of skin difficulties were made to as. A combustible gas indicator was used plication. It appears that xylene or whatever solvent is used for easing the trowel ing and rolling job constitutes the greatest health hazard in application of epoxy-terrazzo flooring but that _the solvent exposure can be reduced to acceptable values with the use of appropriate ventilation. .......... Where the ventilation measures taken are not satisfactory, the use of approved respiratory protective equipment is indicated. It is also reasonable from the point of view of safety that the cleaning of all equipment with a solvent should be done out-of-doors where pos sible. Tools and containers for mixing the epoxy resin floor compounds are usually cleaned with toluene, xylene, acetone, or mixtures of solvents com monly known as lacquer thinner*. The flammability or explosiniHty problem does not appear to be severe but since flammable materials are be ing handled, necessary measures to prevent a solvent buildup to explosive levels or to minimize the possibility of ignition of either liquid or an airvaoor mixture should be taken. The need for ventilation during application of the flooring material has already been noted. There is also a need for good personal hy giene habits among workers to min imize effect of skin contact. Warm water and mild soap should be available so washups may he done as frequently as needed and workers should receive instruction on proper work procedures as well as on the hazards of the materials they arc hand ling. .Solvents uch a- xvler.e and tolu ene should not be used for cleaning the . skin hut rather special skin cleaners should he made available for this pur pose. Since there is a skin exposure problem, appropriate protective cloth ing including gloves should be worn. to determine the concentration of xylene vapors in the breathing zone of the workers during various stages S_ ugges, ted Work Control __ .-_ oh-trowcling and rolling."TrTndicatcd * " ro<e ures "iv"- - vapor concentrations which reached a peak of approximately 600 parts per All workers on the job should \he properly instructed on (lie toxic million when the solvent was first dis nature of materials they are to tributed with a long bristle brash (swishing in the air). In less than a minute, the solvent concentration dropped to about 400 parts per mil handler the proper work procedures to miuimi/e any hazard due to skin contact or mhulutum; ami obviously, proper application tech lion and about eight minutes later the niques to minimize exposure time. Appropriate ventilation sh< he provided wherever the wot being done to minimize the > centrations of amine or sob which might develop. The rati . air flow should be sufficient to k - contaminants at .levels gener below the maximum threshold le Protective work cloth ' should be worn on the job so 1 as much of the body surface - possible is protected. The sv , clothing, particularly the glo- should be impervious to the t terials being handled. Personal hygiene is very portant. Workers should be cottraged to wash up with soap i - water frequently (or use water: cleaners); should minimize the of solvents for skin cleaning (' specially prepared cleaners); : should do all their work in a v as to minimize exposure to any the materials handled.-This-c: for neatness on the /oo. Although the flammabil problem is not severe, it is nev theiess present, since flammal materials particularly solvents ; used and the air vapor concent: tions reached can he relatively hit Accordingly, smokinz as well other sources of ignition should controlled on the job. Fire tinguishing equipment should handy. Respiratory protective equi ment such as chemical cartrid respirators may be required in ct tain areas where hizh solvent co centrations develop despite the u of ventilation. Such respirato should he available on the jo should he kept in proper repair ail times, ami workers should 1 tra...cd is la- such ciu>t.Mviit. Spraying of Asbestos Asbestos is commonly applied interior surfaces. It is used main on exposed steel beams and girders buildings where fireproof constnietit _i> required asjycll .as_o`n veiling ,,ur ceiling aprons of auditoriums ar meeting rooms. Because it leaves finish which is somewhat sott. it limited in use to areas which can t protected either by additional cove ingx or indirectly through inacccss bility. Asbestos coatings may he uppik either manually or pneumatically. T>  Figure 4. Workman leads asbestos for pneumatic feed to spray fun. He*it nor wearing a respirator. information we present is primarily concerned with pneumatic application. LThe principal hazard in spraying as bestos is excessive contamination of the air with asbestos dust particles. Inhalation of excessive quantities of asbestos dust over a period of years on the job can result in serious lung difficulties. The hazards of asbestos spraying are not only limited to the spray operators, but may affect anyone in or near the contaminated work area. Recently, this Division studied a routine asbestos spraying oper ation in which the spraying equip ment consisted of a feeding hopper and a compressor connected with a flexible hose to a gun. Asbestos fibers' from the hopper were fed into the flexible hose and propelled by a blower system to the spray gun where it was wetted with water (sometimes containing an adhesive). The amount of asbestos fibers and water applied in the final mix were controlled with a valving system on Hoch the spray gun and the hopper feed mechanism. ...... Although cmpFoycw^TIbTng'lhir'fifc*' proofing were provided with dust respirators, other tradesmen (electri cians. plumbers, carpenters) were not similarly protected. They complained and a study was conducted quickly. Present maximum allowable con centration for asbestos dust us recom mended by the American Conference of Governmental Industrial Hygienists is 5 million panicles of dust per cubic foot of air. A series of representative work room air samples were collected. Sampling locations were from 15 to 30 feet from the spraying operation and the dust concentrations were found to range from Id to 59 million panicles per cubic foot, considerably above the maximum ailowaole con centration level. Two samples of the spraying materials were lab tested. One was a base coat material and the other a finish coat mix. Analysis shi both materials were nearly percent asbestos with a : amount of filler as a tton-fil nature. .......... ....... Findings of our dust study., discussed with representatives oi contractors, the building trades c cit, and business agents of every \ on the job. We indicated that . concentrations were excessive but the problem could be correctec segregating and ventilating the < ation and/or by the use of aopr respirators hv everyone on the i in which the fireproofing oper: was being carried out. The follow-up visit revealed the fireproofing contractors had vided a large wall fan which used when the spraying was rl Also, the floor on which the < was working was sealed off means of plastic curtains. No o workers were required to worl the floor while spraying was tal place and if one elected to, he supposed to wear a Bureau Mtnes-approved respirator. Th were on hand with each contra- providing them for his own mt In another study in which interior of a dome was being spras the crew was uninformed of the hestos inhalation hazard, respirai were available but not necessa worn, and the dust concentrations ccetied I0-mtllion particles per cu foot of air in the workroom. Bcca of inaccessibility no breathing z 4 samples were collected at the elevated verified similar problems in these fabricating shops where iron c height where the spray operator was locations. pigmented paint is now used, ev* located but it is assumed that the Observation on the fob indicates these places, job orders are recc concentrations there were excessive. a general tack of knowledge of the from time to time where the custc Since the spraying operation is such seriousness of this problem by most insists on lead type paint. that the maximum threshold level will workers and supervisory personnel. Paint manufacturers maintain be exceeded in almost alt instances For example, on a routine highway there arc substitutes- available w where the work is'done unless control measures are appiied. it is reasonable to expect that all asbestos spray con tractors will adequately control the. operations so as to minimize the health hazard to their workers. --------- Suggested Work Control Procedures Educate all workers as to the asbestos toxicity problem and . proper work techniques. ..........- provide adequate ventilation so that the dust concentrations de veloped in the general workroom do not exceed the maximum thresh old level. Wherever possible, segregate the asbestos spraying operations so adjacent areas in the work place are not contaminated with asbestos ... dust. Provide and make the wearing of Bureau of Mines-approved type respiratory protective equipment mandatory where the dust con centrations are excessive. Such respirators should be provided by the contractor. All employees engaged in such work should be given pre-employ ment physical examinations before being hired and should be given periodic physical exams. These ex aminations should include chest x-rays. - bridge maintenance fob involving sand blasting of the painted steel structural members, dhe workers were not wearing respirators. Air samples indicated lead concentra tions ranging from 6 to 116 milli grams per cubic meter and dust concentrations ranging from l IT to 235 millions of particles per cubic foot of air. Lead may enter the body through inhalation, swallowing, or absorption through the skin. The latter can be ruled out in construction work unless gasoline containing tetraethyl or tet- ramerhyl lead is handled by employees in a careless manner allowing it to make direct contact with the skin. Inhalation is dangerous where wire brushing, sanding, or grinding is done, particularly with automatic tools, and where lead-based paints are applied with hot or cold air or airless spray methods. Swallowing is another serious mode of lead entry into the body and reflects personal hygiene habits which have been observed to be basically poor on outdoor construc tion projects. Lead contaminated work clothing, dirty hands, and activities such as smoking and eat ing on the fun site can all result in swallowing hazardous amounts of lead. Our Division fecis the problem is severe and the well-being of many workers is being endangered on an are at least as good as lead coat; Apparently, they have not been ficicntly diligent in proving it. alternative is effective protectior -the worker on the job. tn the area of protective eq ment. respiratory protective dev such as the type approved by Bureau of Mines for protec against lead dispersoid and on ic vapors should be worn by employees engaged in wire bn ins, grinding, automatic a-MtJiug any other type of operation wl produces any appreciable quanti of lead dust. While working to closed areas such as in bridge t< ers or in water _tanks,..-worl should wear Bureau of Min . approved air supply hoods. Sup visors should see that respirat are in good working condition ; see to it that the men wear th as part of the job requirements. Protective clothing is import; since contaminated clothing is a sou; of lead duxu A usual practice is have lead workers tci industry char clothing in locker rooms designed i the purpose. On arrival, worke change into clean work clothes a before departing, are encouraged take showers and change hack ir street clothing. The work clothing then laundered. Outdoor coostn. lion workers, especially, wear t same work clothing for extended f Vacuum cleaner type surface cleaning procedures shott/d be used almost daily hasis. On construction ions, certain environmental control riods ot time. This is a source contamination. in place of manual sweep tech niques. procedures should he implemented for the benefit of all employees including those of the subcontractors. A major contractor may be able to Application of Red Lead Paint put through an adequate program for his own employees because of direct supervision. But the problem is more After several investigations, this Division has confirmed that lend hazard problems on construction and difficult with subcontractors. Possibly, effective control can he initiated as a contract stipulation. - ---highway-work cxisr mainly"axIfresult - ------- Another important consideration of Icad-hused paint coatings used on Is the educational approach through structural steel. Our attention was meetings and in making adequate first directed to this problem as u 'ami carefully prepared material result of reports indicating that paint available to work crews. crew employees on a highway bridge The obvious answer to the lead project hud developed lead poisoning. paint problem is the use of a substi Inquiries since directed to the highway tute paint. While we have been suc Personal hygiene is the most it portant single factor in preventing i gestnm of lead and involves not on routine and deliberate washing of ti hands and face hut a personal co sciousnexs of the need for extren care in handling hazardous materia. Unt water, soap. :uut lowc should he provided so.thaMlu? tm '-- cun keep-" rvMm*tblv clean. Was. up procedures should he %'nfnret - particularly before the mum men ami before workers leave the jt site. The use of waterless cleaners mi he sansfaetorv as a.substitute for sow ami water in the event that they cat departments in other states have not cessful in this approach in several steel not be supplied. The fact that smol 5 ing and placing the hands in or near the mouth also can result in ingestion of lead should be emphasized to the workers. In the care of the eyes and face, the use of face shields or safety glass** should be a mandatory re quirement bn ail jobs where flying debris is present in the atmosphere. This is especially important in wire brushing, grinding, and sanding. Effective supervision is another important factor. An occasional . project engineer sometimes has little actual interest in the health and safety of his men. so it becomes important for the contractor to fol low up on all j'obs to see that con ditions which could endanger health of the employees are controlled. It's an excellent practice to see that all employees are given pre-employ ment physical examinations and that they he checked periodically when they are engaged in potentially haz ardous work. All employees who may possibly he exposed to lead should he tesicd for lead absorption in ac cordance with the program outlined in Volume 5. Issue I t Fall. 1959). Michigan's Occupational Health bul letin. The Division is prepared to collect and analyze urine and blood samples submitted for evaluation of lead absorption where new biological control programs are being instituted. Education of workers as weil as supervisors is unquestionably neces sary. Suggested Work Control Procedures Educate employees os to the lead toxicity problem and in prop er work techniques. * Good personal hygiene habits are particularly* .imuortaiit. Water, soap, and towels should he pro vided and workers should at least wash their hands thoroughly be fore cati< and before leaving their work stations. Waterless hand cleaners should he provided where water is unavailable. Bureau of Miues-upproved respirators should he provided and their use made mandatory where excessive tlusffcrimlimtTThtppint:.' wire brushing) and paint piument (spray pamirnc) are given off. \ Use of frequently cleaned work clothing should he encour aged. Workers should he given preemploymeut and periodic physical examinations. A biological testing procram should be instituted where working with lead is a routine matter. A minimum program follows: Minimum Medical Program This is a recommended minimum lead control program. For ease in interpretation of lead and blood levels, refer to Table l. ,, Incorporate a routine biological test program for all employees exposed to lead. (a) Urine samples to he taken at least even* three months and examined for lead content, (n areas of excessive lead exposure (ate con- , Generations above 0.15 Mg/M') urine samples should he obtained * monthly from exposed workers. (h) Blood samples to he an alyzed for lead to he taken from all workers following urinary lead excretions greater than 0.15 me Ph/l urine. A second urine sample should be obtained .at the same time for lead analysis. (c) Blood and urine samples to he repeated on a monthlv schedule from all workers excreting lead in concentrations of 0.15 me Ph/l urine or with blood levels greater than 0.05 me Pb/100 crams whole blood. (d) Remove workers from lead exposure areas where blond lead concentrations reach a level of O.O.S me Pb/100 crams whole blood or above. Workers should not he re employed in lead areas until bio logical samples indicate reduced levels of lead in these hotly fluids (urine -- equal to or less than 0.15 mu Pb/1 or urine. Blood equal to or less than 0.05 mg Pb/100 whole blood). - Pounng fn Place o Application of Polyurethane Foar. 'The use of polyurethane re both foam products and other sp Items has grown remarkably past few years. The number ol made of polyurethane foam is endless and it enjoys particular tarity in the construction ir basically as an insulating mate The chemical formulation, can be varied to produce urethane products of various cal and physical proper-tie invariably involve a reacti toluene diisocynnate with a ester or polvether type comj During production of the occupational health problems c velop because of the common . toluene diisocvaciate. which is a toxic material. In high concemr TDl can he lethal and in amounts, it is very .irritating mucous membranes, producii asthmatic type effect. Creat care must he taken use and close engineerim medical .supervision of the men arc desirable. Poured-in insulation (between partition: a spray application to suriat steel storage tanks, for examp two Important uses in the cor tion fieid. The foams are ma metering and mixing the c amount of toluene cuisocyauai other required ingredients esters. polyethersi. w:* y.>%*****.*. v;?***>v.?? **.%.W::n*:rfm*.-:->.----- .l:. o i TAiU I 4 INTERPRETATION C? 3tCkCGlCAt. UEAO UmPIES -------------- 0.01 to 0.06 .AVsV 0.C5 to 0.15 0.15 to 0.20 __________ 0.20 Plus Non.QCCueafionql 0.Q2 to Q.Q4 NQ.ccuoationai Normal Iced absorption Re-cheek: 4 to 3 ee* Normal lead absorption 0.(H to 0.07 Occupational Oceuoanonai Notmol leap absorption Rc-chcck 0.07 to 0.C3 Narmoi lead absorption Re.cheek: 4 to it weeks Occupational Occupational Hosoroews lead abtorpti Hosoroout (cod eosoronon ftc-cncck: 4 to 3 ^Re-cheek:-2Vo/4 weexs -- '33 *0.03 ?!ut - -QUMimnf __ Occupational " Absorption compatible Absorption comeotible *ith lead intoxication witn lead intoxication Recommend immediate r Recommend Blood lead test. check and removal (torn Hemoglobin and leed csoosure ores ond Erythrocyte count physical examination Routine urinalysis Physical examination Re-checfc: t to 4 weeks SwnmmuKmVi ..J1I'.1..... .aoM-yw-M-mf--w' *-- ` f. . ' drying up spills. The contaminated 1. "Goggles required. Th absorbent then must be removed quickly to a ventilated location and/or statement Is intended to mean th; the eyes should he completely pr treated with one of the decontamina tected from airborne material. Sue ting solutions. protection .can be achieved by wea Peterson, Copeland, and Hoyle, mg a full-face gas mask, soft-fraxr reporting on the potential health louvered goggles, chemical worket . hazards of spraying polyurethane ---.--right .fitting . rubber goggles, et foam out-of-doors1 have indicated Experience has shown that regul; that -hazardous concentrations of spectacles with or without sid TDI can develop at varying dis shields are definitely not adequa tances downwind of the spray area eye protection. ......... -- dependent upon "distance from the " * -- "In the area where goggles as gun, spray gun elevation, formula- . . - required, some protection for tl tion uses, temperature and humidity hair, clothing, and shoes is ah uf the air, air pressure of the spray recommended. The type of equii gun, rate of adduct (reaction prod ment used is immaterial so long : uct of an excess of TDI with a /. it will protect against contact wit Figur* 6. FtfioMl pretoctiv* devices os a hi/icnoA 0/ s/eos around :h structure polyol) used, configuration and size . sticky particles drifting in the ai of the object being sprayed, wind - Also, in this area, respiratory-pr being sprayed, ind direction, and sproy- painr. If the material is to be sprayed on to a surface, which is typical of the outdoor application to storage tanks for insulation purposes, all of the chemicals used are automatically metered through a special type spray velocity, and the use uf tarpaulins to reduce air turbulence." Based on their findings, there is no question but that the immediate spray crew at the spray point is in a vulnerable position because of the presence of excessive concentrations of TDt and should be provided with - lection equivalent to or better th: an organic vapor respirator shoui be immediately available to all pe sonnel. Such respiratory protectic should be worn at any time whe the characteristic odor- and/or 1 rication of TDI is noticed. . 2. "Coggles and respirator . r< gun unit. If the chemicals are to be and made to wear air supply hoods quired. In this area, both goggli goured between partitions or other and other protective clothing. and respirator should be worn ; ''cavities where it is to foam. gel. and cure it is simply a matter of metering It was also found that in outdoor spraying, the evolution of TDI vapor all times when spraying is bein done. The word goggles has th and mixing the correct amount of from the foam surface, once applied, same meaning as above; and th materials and pouring (hem into the was an insignificant problem. The goggles and respirator could, t mold, in either case, where the foam authors recommend that ail persons course, mean a full-face gas masl is the result of the carefully metered within 150 feet downwind of the spray full-face respirator, etc. Coveral automatic spray system or a manual gun war suitable eye protection. are very desirable as are a h: paper cup muting operation on the Figures 6 and 7 illustrate the recom (either soft or hard) and high rul job site, a potential hazard exists. mended precautions when, spraying hers. Hand protection (gloves 1 TDI. although generally used In outdoors. Definitions of the terms any type) is recommended. amounts required for a complete used in the drawings are as follows: "Coggles and respirator should b chemical reaction, can be given off 'the minimum protective equipmet during the mixing, foaming, and curing procedures or can result from spillage. It can be irritating to the skin, eyes, and respiratory tract, 'cause eye injuries upon direct contact,v and us noted above, cun cause an asthmatic reaction in some people. Also, susceptible individuals for all persons within 10 feet < the spray gun when the gun is nc in use but is connected to th adduct supply line. Such conditioi . may well incur when the gun being cleaned or inspected on th job. may become sensitized to TDI. 3. "Air-supplied hood require* This contaminant can be controlled by providing ventilation and/or re spiratory protective equipment at the various sources of contamination. Also, adequate facilities should be provided for decontamination of work areas-in-case -of .accidental' spills-or* This recommendation is intended t apply to all personnel within l feet uf the spray gun, upwtm downwind, or laterally, while spra* tag is being done. Along with th air-*upplied hood. .imperviui -- gloves-.--tightly-butmneth*'coverall TDI. These should include adequate figure 7. The recommended precaution* and impervious font covering ai floor drainage, hoses, mops, and buck ets. A decontaminant consisting of aqueous 5% ammonia containing 10C& isopropyl alcohol or a water solution of sodium carbonate should be kept on hand. An oil absorbent can he used since it is helpful in thown m thii chart are tirmliar to that* in Figurtv6, bur in this cose the sprar point i* upwind ot the structure being sprayed. `feteryon, J. .. Copeland, ft. A., Hoyl*. H. ft.; Health Hazards ol Spraying ?oWutthana foam Out.af.Joon, American industrial Hy giene Attoctotton Journal VoL 22, September* October, 1962. . also necessary. It should he obvious that the pou mg of fonin-in-phicc msoJnitoo iodoo is also a manor requiring adequa control if the workers arc to be pr* touted. 7 Suggested Work Control Procedures (Indoor) Educate the workers as to the toxic nature of the materials being handled and inform them of the work procedures to be applied. . ... Segregate the area with tar paulin or curtains of some type if spraying is done indoors or if the foam is poured in place or sprayed. in deep mines where air conditioning may apply piaster one week and a is applied (the rock stratum increases be.stos another), and the rough, chan In temperature with depth) and may ing nature of the site all importa; also serve to reduce resistance to air factors. flow. Despite the foregoing, the pro) Fitzpatrick- and others In a recent lem of uncontrolled health hazart paper described the results of their., -.... in construction work can be solve studies in a mine drift at a 4100 foot if there is a determination on ti level where one to two inches of foam part of all involved to do so. Healt were applied using the spray'gun tech and economic considerations leas nique. Methylene diphenyl diisocyan- no alternature but successful coi Provide adequate ventilation ate (MOI) was used in place of tolu ------ trol. .................... * control. In construction work, this is a rather loosely applied term and it is difficult to define here except to indicate that the air volumes exhausted to the outside from the work area should be such that in the general workroom area con centrations of TDt should not be in erscis of the maximum threshtW level of 0.02 parts per million. Where spraying is done, all personnel within 10 feet of the ene diisocyanate and the maximum vaoor concentration was found to be 0.06 PPM. They reported that the particulates from the spray contained reacting MDt in the spray area and for 50 feet downwind and that with adequate respiratory protection (see information on spraying) the airborne particulates containing MOI did not cause any obvious irritation to any of the men exposed. .... Six general methods'which ter to minimize occupational health ha: ards in construction include: (l) ad< quote ventilation, natural or mechan cal. to dilute concentrations of gase vapors, mists, dusts, and fumes to sai ' levels: (2) use of wet methods to alia dust; (3) personal hygiene, indudin frequent wasmng ot the hands an body and frequent changes of clotht to minimize skin contact with cherr ical agents: (-H personal protectiv spray gun should wear air supplied devices, including respirators, glove: hoods, impervious gloves, tightly buttoned coveralls, and impervious foot coverings. Chemical cartridge respirators are suitable for work - ctcnvs involved in the manual pour* ins of resins. In the latter type operation it is important that the metering station be properly ven tilated and that all foam debris and waste paper cups tfnd other con Summary It appears that much of the success in the control of hcaith hazards in construction work is dependent on the requirements of governing agencies, the insistence of the client, the de termination of (he contractors and subcontractors, the effectiveness of the supervisory personnel, and the attitude doming, boots or shoes and ey guards: 15) education by keepin workers informed about the nature c the potentially hazardous substance used and (he physical agents en countered, including suitable protec ttve measures tor each situation: am in substitution of non-toxic of les toxic materials than are common!' used. tainers be kept in a controlled of the workers themselves. location, since these can be sources To the variables just listed, can he of contamination. A considerable amount of develop added the general character of the construction industry, factors %uch as Seheel letter 0.. Warren, John W., laitc Prank J., Jr., Worton, Harold A., Harm E. J., 3earty, Zadert L., ritieamck, Mai ment work in the application of rugged weather conditions, lack of eolm. ana Craft, 3ob F.; A Surrey at a polyurethane foam to miae walls is sanitary facilities, temporary work Aaaiiaenan sf FoWttmhane ?am to Min presently being done. The foam lining is desirable for its insufating properties crews, pressure of schedules to he met. variation in operations t a plasterer Wailt Usmq Mernyiene Otohenyidiisocvnat MOI*. saoer areiented at the Amenco Uawstnal Hygiene Conference, 1963.