Occupational asthma duetooilmists

Twentyfive patients whowere exposed tooilmists attheir placeofworkwere investigated forpossible workrelated asthma. Serial peakexpiratory flowrecordings showed13to havedefinite workrelated asthma, sevenequivocal workrelated asthma, andthree asthmaunrelated towork; twohadnormal recordings. Subjects withworkrelated asthmaoften produced different patterns ofpeakflow responseduring theworking week; patterns also varied between patients. Sixof these patients hadbronchial tests withoilfromtheir place ofwork.Threehadasthmainduced by exposuretounused (clean) soluble oil andonereacted tousedbutnottoclean oil. Thechallenge tests intheremaining twogaveinconclusive results. Itisconcluded thatoccupational asthmaduetooil mists is common, thepeakflow responseisheterogeneous, andtheprovoking agentwithin theoil may varyfromworker toworker. Manyworkers, particularly inmachine shops, are occupationally exposed tooil mists. These mayoccur inhigh concentrations andoften morethan oneoil is inuse.' Industrial oils areincommonuseascoolants, cutting fluids, andlubricants. Three major classes of oils areused:2 (a)mineral oil, whichmaysimply contain anextreme pressure additive; (b)emulsified mineral oil, whichbesides mineral oilandwater contains emulsifiers, corrosion inhibitors, germicides, colourants, anti-foamers, extreme pressure additives, andperfumes (reoderants); (c) synthetic oils, which are alsomixedwithwaterandwhichcontain thesame additives astheemulsified oils butwith themineral oil replaced bya"synthetic oil," such asapolyglycol. Oil diluted with water isoften referred toassuds oils. The ultimate composition oftheoilmistproduced inthe industrial setting depends onthetypeofoil usedand thecontamination that occurs with use, bothfromthe metalthatisbeing cutandfrommicrobiological contamination, thelatter being aparticular problem with suds oil.34 Exposure tooil mists atworkcangive rise toseveral different health problems.5 Reports ofrespiratory problems related totheinhalation ofoil wereinitially limited tothedescription oflipoid pneumonia, 9 though theoccurrence ofthis condition isprobably rare. Somereports havesuggested anassociation with pulmonary fibrosis,'°" buttheevidence forthis is inconclusive. Oilmists havealso beenproposed asa