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Tomise fa, ive pulmo. ` le of these i the othej
ic glucose tble pallia, with non-
{ condition it easy to diagnose and j amenable to local therapy, but
i it complicated by the ^complexity of our technology,
juate labeling, and poor jmmunication between the practicing physician and plant management,
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Occupational Dermatitis From Plastics
MARCUS M. KEY, M.D.,* Cincinnati, Ohio
! rising coo safe drivini to say, but ograms fa it-hour Dtsnt official* m fact thr y are bcinj ee that out and to sup-
int stake Hi sibility and who force.
-rapid scratch reflex in response to itching 'have had survival value in man's evolutionary
nent--favoring the person who responded to the bite of a mite, louse, or bed bug. We |]onger have these classic causes of itching with us, T&we still have with us the $200,000,000 itch
i as occupational dermatitis. Unfortunately the |5r reaction time from exposure to onset of itching
pational dermatitis is measured in hours or ^ which is too long for itching to have any wam-
ilue. Instead we must rely on education, hy, and engineering controls. The causes and pre-
of occupational dermatitis are conveniently by examples from the manufacture and
ation of plastics and resins.
Oaaeificatlon of Plastics
i were so named because they can be shaped : any form. For thermoplastics, this prop-
be produced repeatedly by the application and/or pressure, hot with thermosets, the shape can be produced only once, as they harden with the addition or production of athetic resins or iesinoids,- from which some are made, were named from their resemto natural resins. Plastics is a term preferable > when speaking of the group as a whole, but preferred when speaking of a plastic made resin-like material, e.g., epoxy resin.
ceor,a
J the Georgia Society of Dermatology, May 5, 1968. Medical Director: Chief. Clinical Services; Occupa-
Programs, as the National Center for Urban and In(JfaafrA, V. S. Department of Health, Education and Welfare, um-j-----Cincinnati. Ohio 45202.
ember ims, voi. 57
Besides the classification of plastics into thermo- plastics and thermosets, and into family groups based on their chemical composition, they can also be classified as addition polymers and condensate poly mers. The former are made by the addition of a large number of identical molecules, called monomers, in to a long chain (illustrated by polyvinyl chloride). The latter are made by the combination of a num ber of molecules, not necessarily of the same com position, with the liberation of water, carbon diox ide, or other simple substance (illustrated by the condensation of bisphenol and epichlorohydrin to form an epoxy resin).
No Dermatitis From End Product
The chemical spectrum of plastics seems to be without limit, yet there is practically no dermatitis from the end product, which is usually completely cured or polymerized. Most of the industrial derma titis that occurs, occurs in the curing or hardening of several thermosetting resins, notably phenolics, ami nos, epoxies, and polyesters.
The dermatitis associated with the manufacture or application of plastics and resins is caused by mono mers, low molecular weight polymers, condensate components, fillets, and also by other chemicals which are added for various reasons, such as crosslinking agents, catalysts, accelerators, plasticizers, and solvents. The dermatitis produced by working with the various plastics and resins is similar in ap pearance, differing only in acuteness and location.
The acute stage, manifested by erythema, edema, and vesicles, and accompanied by pruritis, can be
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DERMATITIS / Key
example, in the manufacture of dufabfc ments, cutters and sewers handle the _
caused by either irritating chemicals or sensitizers.
intimately exposed to the resin in an u
The chronic stage, which is the end result of repeated
Formaldehyde, liberated from the resin t
acute attacks or the result of exposure to low-grade irritants such as solvents or harsh cleaners, has a
irritates the eyes, nose, and throat whe is inadequate, but the garment workers?!
dry, scaly, fissured, and lichenified appearance and
velop dermatitis. Complete curing is j
is also pruritic.'
during the final pressing and heating oc..
Patch Test The skin is limited in the ways it can react, and
in this stage the resin is not hazardous.-^
ception is allergic contact dermatitis fronTi hyde in the finished garment.*
it is almost impossible to distinguish ctinically be tween irritant contact dermatitis and allergic contact
Epoxy Renin Systems
dermatitis. This is why occupational dermatologists
frequently make use of the patch test, which attempts
to reproduce allergic contact dermatitis at the site of
application of the suspected chemical in a non-irri
tating dilution.
.,
As mentioned above, there are four troublesome
family groups of plastics which are associated with
occupational dermatitis--phenolics, amino*, epoxies,
Epoxy resin systems have -caused mor tional dermatitis in recent years titan any < industrial material.4 They were deveh early 40's by Ciba in Switzerland and same time by Devoe and Reynolds in states. The Swiss were several years United States in production of epoxies recognizing the related dermatitis.
Jr
1 and polyesters--the subject matter of this presenta tion. In addition, attention will be called to two other
Production in the United States began* and has reached about 100 miltiTM
family groups, the polyvinyls and polyurethanes,
name is derived from epoxide linkages.-.1
which recently have been implicated in some unusual
chain compounds, originally made from thej
hazards.
sation reaction between bisphenol A and
Formaldehyde Resina The phenolics and aminos can be considered to
hydrin, more recently are derived from polyolefins. Curing or hardening agents (amino,' amides, anhydrides) cross-link the chain* it epoxxk I
gether as formaldehyde resins. The oldest of these
and hydroxyl groups and produce three dimentiopd
is phenol-formaldehyde resin or "Bakelite," .de stability.
veloped in America in 1909 by Baekeland. The most
Epoxies have seen wide use as
recent use of phenolics has been as an ablation-type heat shield for reentry vehicles. Substituting cashew
bonding agents, casting and potting materials, fibjranr glass reinforced laminates, and resistant coatfngt
nut shell liquid (which has many hydroxyl groups)
Their use in constructing the restaurant in there
for phenol produces cashew nut shell liquid-formal
of the needle at the Seattle World's Fair ano^i
dehyde resin, from which automotive brake shoe
making terrazzo floors gave them a bad reputatioo :
linings are made. Substituting urea, melamine, or
among the construction unions because of the>higH
similar chemicals produces the amino resins, which
incidence of dermatitis among workers. As highlit
are used similarly to the phenolics as wood glues,
40 per cent of exposed workers have developed
laminates, and molding materials. The aminos have- dermatitis, much of which was allergic in natures^
long been used as textile finishes, but the recent de
The dermatitis potential of epoxy resin systemsa
velopment of durable press clothing has greatly in
summarized in Table I. Unprotected mixing and';UK:
creased their demand.
results in irritant contact dermatitis (illustrated Sf
Dermatitis produced from contact with formalde
dermatitis on the wrist of a chemist where hc-wa*
hyde resins, illustrated by plywood glue dermatitis
splashed with an epoxy resin) and In allergic contact
and by dermatitis from fabric finish in a "lace ten
dermatitis (illustrated by dermatitis on the face-and
ter," may be irritant or allergic, caused by the phe-
arm of a worker exposed to a volatile aliphatic'
' nolic or amino component, formaldehyde, or an in- amine). Metaphenylenediamine, an aromatic amine
f termediate reaction product.1'1 Hexamethylenetet
hardener, stains exposed skin a brownish color, not
ramine, a formaldehyde liberator, used as a stabilizer
unlike its cousin paraphenylenediamine, a hair and
and catalyst, can also cause dermatitis.
leather dye. There has been an exemplary attempt
For the phenolic and amino resins, there are
within the plastics industry to classify the toxic prop
several degrees of cure, and contact with any except
erties and local action of epoxy resin systems and'to
the last is potentially, but not always, dangerous. For
establish standard precautionary measures. ?&_
422
J.M.A. GEORGIA
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Polyester Resins
sociated with acroosteolysis. Cause is unknown, but
Polyester resin production, now over 250 million | -pounds annually, began early in World War It, stun
^Jated by applications in the aircraft industry-
exposure to the vinyl chloride monomer or to a peroxy-compound is suspected. The acroosteolysis is usually reversible if detected early.7' *
glazing, protective shields for self-sealing gas | Jarfe, and radar housings. Fibrous glass reinforced
polyester resins are molded in a number of ways-- `jjiand lay-up, spray-up, or by matched metal die !g[ding. Examples of application include boat hulls,
car bodies, automotive body putty, chairs, helmets, and decorative translucent panels, i of the early classifications for polyesters gives
to their chemistry--alkyd (derived from ohol and aCID, the reaction product of which tester). Polyester resins are frequently modified
ie, which acts as a cross-linking agent, natitis may result from contact with the polyester 'styrene, organic peroxide catalysts,plasticizers,
elerators pnd may be due to irritation or serr ation. Fibrous glass spicules embedded in the [cause an inordinate amount of itching, and most
dermatitis produced from this exposure is by scratching. Solvents are responsible for >f the dermatitis seen in polyester fabrication. i and ketone solvents produce the typical picchronic contact dermatitis--dry, scaly, fis; and lichemfied skin.*
ts and fibrous
latings.
he eye
and in utation
ic high
ligh a* /eloped
tune,
Polyvinyl*
npared with die preceding plastics, the poly^have a good reputation, and even the manu-
of this plastic was thought to be safe. The i of dermatitis that have been reported were
_by sensitivity to a plasticizer in the vinyl.* recently acroosteolysis, or loss of bone in
of the fingers, was observed in polycleaners aen who dean hardened polyvinyl chloride
ion kettles. It was first seen about 1964 occurred In several factories in the United a*nd Europe. Raynaud's phenomenon and a ke thickening of the skin are sometimes as
Polyurethane*
The polyurethanes (isocyanate resins) are the newest of the plastics. Isocyanate monomers are ir ritating to the skin, but because of precautions taken to prevent respiratory tract irritation and sensitiza tion, there has been very little dermatitis from the manufacture and spraying of polyurethanes.* Cuta neous sensitivity to toluene diisocyanate (TDI) has been reported in workmen protected by air-line res pirators, but is rare.10 Aliphatic amines and organic tin compounds, used as catalysts, are strong primary irritants but are diluted in the foam mix and are not as irritating as TDI. If the hot reacting foam gets on the Sirin, it can cause an irritant dermatitis, and the solvents ftnethylene chloride, methyl chloroform, or
dimethylfonnamide) used to dean guns and lines can also irritate the skin. Except for rare sensitiza tion to spandex11 a polyurethane elastomar, the finished product is innocuous.
One of the isocyanates, methylene diphenyl diiso cyanate (MDI), has been associated with an unusual soiling of the hands among foundxymen using a new no-bake binder. The other components are an. aircuring oil such as linseed oil and a metal-drier cata lyst such as cobalt naphthenate. The isocyanate cross-links the oil and provides sufficient strength to permit stripping and handling prior to air curing, hut it also binds dirt and graphite so firmly to the hands that cleaning is almost impossible.1*
Prevention of dermatitis can be achieved by en vironmental methods and personal methods. Sub stitution is high on the list of environmental methods, but is seldom feasible because product specifications usually take precedence over hygienic considerations. Of the epoxy hardeners available, one, polyamide resin, is worthy of mention because it seldom if ever produces dermatitis.
.terns i*
jndu* ited by
he was contae1 ace and
iliphatif
; amine
,lor. net iair and
attemr* iepror 5 and ip
- TABLE I DERMATITIS POTENTIAL. OF EPOXY RESIN COMPONENTS
Put Irrifetisn proportional
p wotaculmr mUt E* .
BUja -
Sr' *
1fer-
Components
Uncored liquid epoxy rosins '
Uncured solid epoxy resino Reactive diluent* Amine hardeners Anhydride hardeners Polyamide resin hardener Cured eooxy resin* Fibrous (lam Solvents (ketones, esters, ethers)
''
Sensitization
VT_______ -- -
Raw tTnffiomfiMm Common Rare None None None Raw
ORf"M
SEB 1968, Vol. ST
423
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DERMATITIS / Key
- Contact Can Be Minimized
In manufacturing items from plastics and resins, enclosure of the process is seldom practicable, but the process usually can be isolated as in a resin-mixing booth. Exhaust ventilation can be provided at the booth or at imbedding and encapsulating machinesPush-pull ventilation is helpful in controlling fibrous glass dust generated by sanding fibrous glass rein forced plastics. Alternately, housing and a vacuum cleaner line can be attached to sanders and routers. Proportional pump mixers dispense the correct amount of hardener for a given amount of resin, and paper containers minimize clean-up. Good house keeping is important, not only in minimizing contact, but also in inspiring the workers to be cleaner.
Protective Clothing and Ointments %
Of the personal methods which are available, pro tective clothing is the safest Care must be taken in selection of gloves and apron which are not adversely affected by the resins and solvents. Protective oint ments have their place for those workers who can not or will not wear gloves; their use insures a cer tain amount of hand washing, but protective oint ments are of little value after sensitization has oc curred. Soap and water wash-up is seldom sufficient to remove tenacious resin soils. Sparing use of sol vent on a cloth or a mixture of equal parts of acetone and sulfonated oil is helpful in removing resins, but this should be followed by soap and water washing. Many resin shops now supply an emollient for use after water washing to minimize drying and chapping in the winter time.
Of further help in preventing occupational skin diseases would be a labeling law for industrial chem icals and upgrading of State and local occupational health agencies. Industrial hygienists and physicians in these agencies can help in improving communica tions between the practicing physician and plant management
In spite of preventive measures and con dance, there will still be a few cases of < dermatitis. The combinati n of forgetfu mitiarity, and ingenuity in circumventing com almost unbeatable. However, even in defeat] may be some recompense. There is a certain' of pleasure associated with the ability to scrati this gratification is so intense that some in ^'' overscratch with a vehemence that passion. Ogden Nash summed it up very follows:
One bliss for which There is no match Is when you itch To up and scratch.
REFERENCES
1. Malten, K. E.. and Zielhuis, R. l_: Pi
Toxicological and Dermatological Industrial Hi
sevier Publishing Company, Amsterdam and
Jersey, 1963.
2. Malten, K. E.: Textile finish contact h;
Arch. Derm. 89:215, 1966.
3. O'Qumn, S. E,, and Kennedy, C B.: Contact
titis due to formaldehyde in clothing
JAM.
593, 1965.
M
4. Birmingham, D. J.: Clinical observations on 3&
taneous effects associated with curing epoxy resins; AM,
Arch. Indust. Health 19:365. 1959.
3. Key, M. M., and Discher, D. P.: Polyester
their dermatologic aspects in industry; Cutis 2:27Uflr7*'
1966-
`-'o. Morris, O. E.: Vinyl plastics, their dermatoli^r
chemical aspects; AMA Arch. Must. Ryg. A Occupy
8:535. 1953.
.
7. Wilson, R. H., McCormick, W. E., Tatum, C.
Creech, J. L.: Occupational acroosteolysis; JAMA 20135
1967.
8. Harris, D. K., and Adams. W. G. P.;
occurring in men engaged in the polymerization oi
chloride; Brit. Med. J. 3:712 (Sept. 16) 1967.
9. Fisher, Alexander A.: Contact Dermatitis;
Febiger, Philadelohia, 1967. Chapter 8.
10. Dernehl, Carl U.: Health hazards assodal
polyurethane foams; /. Occup. Med. 8:59. 1966.
11. Joseph, H. L. and Maibach, H. L: Contact
from spandex brassieres; JAMA 201:880, 1967. ,3,
12. Arndt, K. A., Perone, V. B., and Tubich,
Stained bends in the foundry; Arch. Environ. HealthJ
1968.
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