A Review of the Health Effects ofEnergy Conserving Materials

LESTER LEVIN, MS, AND P. WALTON PURDOM, PHD

Abstract: The energy conservation movement haspromoted both greater use of insulating materials andthe reduction of heat losses by sealing air leaks. Therelease of volatile or airborne materials from theinstallation of these building materials under theseconditions has resulted in an exacerbated indoor airpollution with the potential for certain health andsafety hazards. Consequently, a comparative reviewof the health and safety hazards, exposure standards,and regulatory action associated with the more com-monly used insulating materials with particular respectto current energy conservation measures was under-taken. The materials reviewed included asbestos,

Introduction

There are many health and safety hazards associatedwith building materials; however, this paper deals specifical-ly with health hazards related to building materials used forenergy conservation. Hazards commonly associated withglass doors, aluminum wiring, lead solder, paints, adhesives,and similar materials not specifically related to energyconservation have been excluded.

Some of the health problems associated with buildingmaterials are created or increased when building heat lossesand, consequently, the general ventilation of interior spacesare reduced. For example, natural radon gas emissions fromdecay of radioactive materials in soil, rock, concrete, andbrick and volatile or airborne materials from plastic orinsulation materials may be concentrated to produce airpollution.' This paper examines the inherent characteristicsof the building materials that cause problems, rather than thereduced ventilation rates which exacerbate them.

In addition to the occupants, building materials mayalso present hazards to installers, firemen, and maintenanceand repair personnel.

The materials described are those specifically used for

Address reprint requests to Professor Lester Levin, Professorof Industrial Hygiene, Environmental Studies Institute, DrexelUniversity, Philadelphia, PA 19104. Dr. Purdom is Director of theInstitute. This paper, submitted to the Journal June 11, 1982, wasrevised and accepted for publication September 9, 1982.

© 1983 American Journal of Public Health

urea-formaldehyde foam, polyvinyl chloride, cellulos-ic insulations, fibrous glass, mineral wool, and vermic-ulite. Although no longer used, the past installation ofasbestos in a friable form is the greatest potentialhealth hazard. The exposure to formaldehyde gas fromits release from urea-formaldehyde foam has elicitedsubjective complaints of sensory irritation and unre-solved controversy and regulatory action regarding itstoxicity to humans. Lesser health problems have beenassociated with the more widely used fibrous glass andmineral or rock wools. (Am J Public Health 1983;73:683-690.)

insulation or barrier purposes, including: asbestos, urea-formaldehyde foam insulation, polyurethane and polysty-rene rigid insulating board, polyethylene and polyvinyl chlo-ride sheeting, cellulosic insulation, fibrous glass, mineralwool, and vermiculite.

The amount of insulation appropriate for a particularhome depends on the local climate and the cost of energy.2The United States climate zones for heating purposes areshown in Figure .3 The insulating application may combineboth heat reflectance, as with aluminum foil, and resistanceto heat transfer, such as an air space or fibrous glass. "R-values" are used to compare the ability of materials to resistheat conductance. The higher the R number, the greater theinsulating properties. Recommended R-values for ceiling,walls and floors in various climatic zones for energy conser-vation are shown in Table 1.3A comparison between variousinsulating materials (Table 2) indicates that some of the rigidplastic foams have higher insulating values for the samethickness than other materials.

Asbestos

Some of the uses of asbestos described are no longerpermitted by law in the United States; nevertheless, theeffects of its use will probably be experienced for manyyears.

Asbestos is a broad term applied to nutnerous naturalfibrous mineral silicates that have a high fusion temperature,but are completely decomposed at 1000°C. Because of their

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HEATING ZONE MAP

FIGURE 1-Heating Zone Map, United States

thermal and chemical resistivity, tensile strength and fibrousproperties, they are used in many commercial productsincluding: cement asbestos pipe, flooring products, frictionmaterials (such as brake lining and clutches), roofing prod-ucts, paint, coating and patching compounds, and insulation.Production in the United States in 1978 was 900,000 tonswith more than 70 per cent in the construction industry.4

Sprayed fiber insulation material containing asbestoswas first used in Great Britain in 1932 and subsequently inthe United States in 1935.5 First used for condensation andnoise control, and later mainly for thermal insulation, somewas used for purely decorative purposes. Asbestos useexpanded rapidly after World War II, and was treatedsomewhat casually inasmuch as its health hazards as ahuman carcinogen were not generally known until the early1960s. Spackle and filler for do-it-yourself household repairsand wallboard joints often contained 10 per cent or moreasbestos without any notation on the labels.6 Mixing andsanding these compounds would increase dust levels andexposures to asbestos fibers in interior spaces. This expo-sure is of particular concern because it was in a confinedspace and could persist for a long period of time withreentrainment. On December 15, 1977, the US ConsumerProduct Safety Commission finally banned the use of respi-rable asbestos particles in patching compounds and artificialemberizing materials under the Consumer Product SafetyAct (16 CFR 1304 and 1305, 42 FR 63354).

From 1958 through 1973, friable sprayed material con-taining 10 to 30 per cent asbestos by weight was usedextensively to fireproof girders and decking in high risebuilding.7 Asbestos was also used to insulate heating and airconditioning ducts and for decorative and acoustical pur-poses. It was widely used in gymnasiums, hiallways, audito-riums and classrooms in schools, libraries, record storageareas, offices and elsewhere.4 Reitze, et al, estimates that in1950 one-half of the high rise buildings built in the UnitedStates used some form of sprayed-on mineral fiber fireproof-ing.8 Because of fugitive dust emission into the environment,use of sprayed-on asbestos materials was prohibited in 1970-1972 in several cities and states including Boston, New YorkCity, Philadelphia, and Illinois as summarized by Nicholson9and throughout the United States in 1973 by the US Environ-mental Protection Agency as a National Emission Stan-dard.'0

Subsequent to the ban, the sprayed-on asbestos remainsthe most significant cause of indoor airborne pollution byasbestos. As the material deteriorates and flakes off with ageor is cut or abraded in repair and remodeling work, or struckaccidentally, asbestos particles with fiber lengths from 1 to 5microns become airborne and the smallest of these mayremain so for up to 80 hours or be reentrained.5 All occu-pants of the building are then potentially exposed.

In addition to asbestosis, persons exposed to asbestoshave a higher risk of developing lung cancer, mesothelioma,

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TABLE 1-Recommended R-Values for Heating Zonest in theUnited States*

Recommended forHeatingZone Ceiling Wall Floor

0-1 R-26 R-13 R-1 12 R-26 R-19 R-133 R-30 R-19 R-194 R-33 R-19 R-225 R-38 R-1 9 R-22

tSee Figure 1 map*From Ref. 3

and certain gastrointestinal cancers.6 Asbestosis is an irre-versible and progressively disabling lung disease resultingfrom the retention of inspired asbestos particles in the lungs.Among asbestos exposed shipyard workers, 38 per centwere reported to have developed asbestosis after 20 years.6A nonsmoker exposed to asbestos is five times more likely todie fronm lung cancer than a similar nonsmoker who was notexposed." An exposed smoker, however, is 53 times morelikely to die from lung cancer than an unexposed nonsmokerand up to 11 times more than an exposed nonsmoker. Beforeregulations were adopted limiting worker exposure to asbes-tos, 20 to 25 per cent of exposed workers died of lung cancer.Wagner first reported that occupational exposure to asbestoswas associated with the development of mesothelioma, anormally very rare cancer of the membrane lining of thechest and abdominal cavities.'2 Seven to 10 per cent ofexposed asbestos insulation workers die of mesothelioma.'3Since one clearance mechanism for the lungs is to cough upmaterial, some of which is swallowed, asbestos insulationworkers are more likely to die of cancer of the gastrointesti-nal tract than those not exposed.

Lung cancer rates in people exposed to asbestos arereported to rise 25 years after first exposure. The majority ofthe cases of mesothelioma occur after 30 years. In animaltesting, all types of asbestos commonly used in commercialproducts have produced cancer at the concentrations ordoses applied to rats.7

Asbestos work standards in most industrial countriesregulate worker exposure to protect against the noncarcino-genic effects, i.e. asbestosis, and to reduce materially therisk of asbestos induced cancer (for US values, see Table 3).Since many government agencies and some occupationalhealth scientists believe that there is no safe or "threshold"dose for a human or suspect carcinogen, it has been impliedthat only complete avoidance of exposure can assure protec-tion against the carcinogenic effects of asbestos.'4

In 187 measurements of urban atmospheric concentra-tion of asbestos by election microscopy, Nicholson15 found99 per cent of the values were below 50 ng/m3 and 63.6 percent were below 2 ng/m3. Sawyer'6 compared interior con-centrations with a background outside the buildings of fromzero to 48 ng/m3.

With respect to interior concentrations, Nicholson5surveyed 10 New Jersey public schools where there weredamaged asbestos surfaces and reported concentrationsranging from 9 to 1950 ng/m3. The highest interior samplewas taken after routine cleaning of a hallway where therewas no visible presence of asbestos. Other states have foundairborne asbestos exposures in their schools, and compara-ble levels have been found in other kinds of buildings whereasbestos had been similarly used.

Since the asbestos fibers will continue to be releasedgradually as the material deteriorates, three remedial solu-tions have been proposed:5" 7

* complete removal,* sealing, and* enclosure.

Enclosure is a questionable procedure since it leaves theasbestos in place as a hazard any time repairs are made thatrequire opening the enclosed space.

Complete removal requires isolating and securing thearea to be treated. Within the work area, protective clothingand masks have to be worn and precautions have to be takento prevent the scattering of the asbestos as it is removed,including the use of wet methods and special vacuumcleaning procedures. Removal of the debris and its disposalare also problems. Complete removal has the advantage thatthe problem is entirely eliminated although it is the mostexpensive of the remedial measures and the area cannot be

TABLE 2-Comparison of Insulating Value of Various Materials*

Batts or Blankets Loose Fill (Poured-In) Rigid Plastic Foams

Glass Rock Glass Rock CellulosicR-Values Fiber Wool Fiber Wool Fiber Urethane U-F Styrene

R-1 1 31/2-34" 3" 5" 4" 3" 11/2" 2" 21/4R-13 4" 41/2" 6" 41/2" 31/2" 2" 21/2½" 23/4"R-1 9 6-61/2" 41/4" 8-9" 6-7" 5" 23/4" 23/4" 41/4"R-22 61/2" 6" 10" 7-8" 6" 3" 4" 41/2"R-26 8" 81/2" 12" 9" 7-71/2" 33/4¾" 5"1 51/2"R-30 91/-1 01/2" 9"t 12-13" 10-11 " 8" 41/2" 53/4" 61/2"R-33 1 1" 1 O0" 15" 1 1-12" 9" 43/4" 61/2" 71/4"R-38 12-13" 101/2" 17-18" 13-14" 10-11" 51/2" 71/2" 81/2"

*From Ref. 3

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TABLE 3-Occupational Asbestos Exposure Standards andRecommendations

Fibers/cc of Air Fibers/cc of AirAgency/year Time Weighted Average Ceiling Limit

OSHA 1972 5.0 10.0OSHA 1976 2.0 10.0OSHA, proposed 1975 0.5 5.0NIOSH, revised 1977 0.1 0.5

Note: These values are not intended for general population exposure.

used while removal is in progress. It is the preferred methodfor loosely bonded friable materials and in case of highoccupancy, accessibility, and exposure risk, it is the onlyfeasible procedure.

Sealing involves applying a penetration polymer oradherence type material to the surface. Twelve sealantscomprising five classes of sealant materials were reviewedby Nicholson.5 One method uses an acrylic copolymer intwo applications. The first one penetrates and holds thefibers in place and the second provides a 45 mil (1.143 mm),flexible fireproof membrane over all the asbestos. Precau-tions similar to those which had been used in removing thematerial have to be taken except there is no disposalproblem. Proponents claim this method costs one-fifth thatof removal. This procedure will work where the materialremains intact, but Nicholson claims it is not successfulwhere there is loosely bonded friable material.

Urea-Formaldehyde Foam

Formaldehyde was first manufactured commercially in188918 and is now used in thousands of industrial andconsumer products and widely applied in the textile, furni-ture, automotive, machinery, energy, construction, and con-sumer industries. Formaldehyde reactivity makes it particu-larly applicable as a chemical bonding agent in polymers andresins. Ninety-five per cent of hardwood panels are manu-factured with formaldehyde resin adhesives.

Urea-formaldehyde foams were developed in Europe in193318 and have been used in northern Europe as an insulat-ing material since the early 1960s. Most installations in theUnited States were made after the 1976 energy shortage.Dally, et al,'9 summarized European and US reports ofindoor residential formaldehyde concentrations resultingfrom the installation of formaldehyde containing wood prod-ucts used in construction and from urea-formaldehyde foaminsulation (UFFI). Their own surveys of 100 Wisconsinresidents indicated mean formaldehyde concentrations frombelow the limit of detection (0.1 ppm) to 3.68 ppm.

Urea-formaldehyde foam insulation (UFFI) is preparedby an installer in the field at the time and at the place of use.It is made from urea formaldehyde resin and a surfactant(called a foaming agent or catalyst), with an air mixingsource. An air compressor and a mixing foaming gun form aresin coating foam that surrounds microscopic air sacs whichharden (cure) in a few days or weeks.

At first, UFFI appeared to be especially well suited forfilling cavities in exterior walls of old uninsulated homes.However, consumer complaints of formaldehyde odors andeye and upper respiratory irritation began immediately andhave persisted.20 Some occupants of treated homes claimedthat they were made ill and had to move out of their homes.

Subsequent investigations have shown several factorswhich can contribute to problems with UFFI.'8 These in-clude:

* Excessive amount of formaldehyde in the resin* Excessive amount of catalyst in the foaming agent* Improper ratio of resin to foaming agent* Excessive amount of foaming agent* Foaming at high humidities* Foaming with cold chemicals* Dry density of the foam exceeding manufacturer's

specifications.

Odors and eye and respiratory problems result because theformaldehyde based insulation and adhesive resins containfree formaldehyde that in the short-term escapes as a gas. Ona longer term, heat and moisture cause hydrolysis anddecomposition that also result in the release of the formalde-hyde vapor. The poured-in-place foam may deteriorateabove 27°C (80°F) and will not properly harden below 12°C(53°F).

In preparation for this paper, the authors surveyed stateand federal health agencies for information regarding expo-sures resulting from the use of building materials and theirpertinent requirements or regulations. Several agencies re-plied that they had no requirements regarding either thematerials or the indoor air quality in homes. Interestingly,virtually all of the positive responses dealt with the thencurrent problem of formaldehyde release from UFFI.

Idaho reported that there have been problems duringnormal occupancy associated with UFFI, as well as fromparticle board, plywood, and wood paneling.* Tennesseereported there had been several complaints of sensoryirritation from both UFFI and new paneling.** Indianareported some surveys that found measurements indoors of0.02 to over 1.0 ppm of formaldehyde in which occupantsreported symptoms varying from eye irritation to breathingdifficulties.*** Kentucky reported 300 complaints in 14months, ten percent of which were from use of UFFI inconventional homes and 90% were from mobile and modularhomes where particle board and paneling were used. Thehighest level found was 1.77 ppm.t In 1979 and 1980,Montana performed 54 investigations reporting levels from0.023 to 0.86 ppm in mobile and modular homes and from nil

*Personal Communication: Burkhardt HI: Department ofHealth and Welfare, Idaho, July 1980.

**Personal Communication: Foster RI: Department of PublicHealth, Nashville, TN, August 1980.

***Personal Communication: Konopinski VJ: Director of In-dustrial Hygiene and Radiological Health, Indiana, July 1980.

tPersonal Communication: Moore EE: Department of HumanResources, Commonwealth of Kentucky, July 1980.

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to 0.62 in residences. The UFFI residences had been foamedbetween 1976 and 1979.t#

Several studies have been made concerning the effectsof human exposure to small concentrations of formaldehydegas. Suta2' and Garry22 both state that a person can smellformaldehyde gas at 0.05 ppm. Swelling of mucous mem-branes occurs between 0.05 and 0.1 ppm and irritant effectsoccur at 0.2 ppm. This may involve burning of eyes, weep-ing, and irritation of upper respiratory passages. Above afew ppm there is coughing, constriction of the chest, and asense of pressure in the head. Diarrhea, nausea, and skinirritation may occur but, most significantly, there may be anallergic response or sensitization to formaldehyde exposure.

The US Consumer Product Safety Commission reportedthat, since 1978, 28 persons have been hospitalized and 68vacated old homes, or could not move into new homesbecause of formaldehyde gas.23 This Commission in 1979requested the National Academy of Sciences to renew andevaluate the literature to determine if there was a tolerablelevel of long-term continuous exposure to formaldehyde gasin the home.24 The Academy reported that formaldehyde gasis mutagenic using non-mammalian test systems-microorga-nisms and insects, but was negative for the Ames test. Thereport concluded that there is no population threshold forirritant effects of formaldehyde in humans, but research isneeded to assess fully the health effects. It was recommend-ed that formaldehyde be kept at the lowest practical concen-tration in indoor residential air.

The Academy acknowledged that its report had beensuperseded to some extent by a preliminary report of anongoing inhalation study by the Chemical Industry Instituteof Toxicology in which nasopharyngeal carcinomas werefound in 36 rats exposed to 15 ppm, 6 hours per day, 5 daysper week for 18 months with histologic changes at exposureof 6 and 2 ppm.25 However, a recent epidemiological studyby DuPont Company found no overall excess of cancerdeaths in occupationally exposed persons compared withother non-exposed employees.26 Adequate employee protec-tion, it was claimed, was provided by maintaining airborneexposure levels of 1 ppm as a time-weighted average and a 2ppm ceiling limit.

Reactions of state and local agencies have varied. OnDecember 4, 1978, the Rocky Mountain Poison Center inDenver issued a position paper,27 and on that same date, theColorado Attorney General issued a "Public Warning"concerning urea formaldehyde foam.

The Connecticut Department of Health Services28 in-vestigated 2,828 cases, and found that 52 to 66 per cent whoreported symptoms were exposed to less than 0.5 ppmformaldehyde and odor was detectable at 0.6 ppm. TheAttorney General of Connecticut worked out an agreementwith industry (nine companies) whereby the companies wererequired to issue notice regarding adverse effects and sensiti-zation. There are also suggestions for a procedure to obtainremedy of a complaint, e.g., sensory irritation. In practice,individuals have to prove that they required medical atten-

tlPersonal Communication: Hooper WA: Department ofHealth and Environmental Services, State of Montana, July 1980.

tion in order to obtain intervention by the Attorney Gener-al's Office.

Since February 1, 1979, the Minnesota Department ofHealth has investigated 575 complaints about formaldehydeproblems in homes.tt# Subsequently, the 1980 legislaturepassed a bill whereby the Health Department was authorizedto set a maximum concentration of formaldehyde gas at thetime of sale for homes completed after December 15, 1980. Atemporary emergency rule was adopted setting the limit of0.50 ppm. However, an injunction was obtained December5, 1980, which delayed enforcement.29A prepurchase notifi-cation required by the bill was not altered and this require-ment was made effective January 1, 1981.

Legislation was considered in 1980 to regulate UFFI inCalifornia.30 This bill would have limited emissions of form-aldehyde to not more than 2 mg per hour per kilogram ofinsulation at 45°C and 90 per cent relative humidity. This billalso set a limit for formaldehyde concentration in inhabitedportions of residential or commercial structures of 0.2 ppm.It also required training and certification of installers and a$100,000 bond to cover any remedial action required. Evenwith these provisions, UFFI could be prohibited if it wasdetermined to be carcinogenic, mutagenic, and teratogenic.This bill did not pass because of budgetary considerationsand the agency delegated the responsibility did not have theresources for implementation.*

Massachusetts had taken the most direct action of anystate. Public Health Commissioner Alfred L. Frechetteissued a complete ban on the use of UFFI effective Novem-ber 14, 1979.31 After public hearings, he concluded that theproblems were not "due solely to faulty installation," andthat problems did not seem to be "associated with only onemanufacturer, but rather with the product itself." The banwas subsequently overturned by the State Superior Courtbut is still in effect pending appeal to the State SupremeCourt.** Massachusetts' tests of 73 homes by requestshowed 26 per cent with less than 0.1 ppm aldehydes, 50 percent with more than 0.1 to 1.0 ppm, and 22 per cent withmore than 1.0 to 2.9 ppm. These values compare with anOSHA (Occupational Safety and Health Administration)value of 3 ppm, as an eight hour time-weighted average andNIOSH (National Institute for Occupational Safety andHealth) recommended ceiling limit of 1 ppm for 30 minutes(see Table 3).

While there seems to be action regarding UFFI, noinformation concerning action aimed specifically at ureaformaldehyde adhesives used in particle board and panelingwas received although 60 per cent of the urea formaldehyderesin produced in 1978 was reported to be used in particleboard and medium density fiber board.32 It is less costly thanphenol formaldehyde resin; however, the latter does nothave as much problem with deterioration and offgassing.

tttPersonal Communication: Oatman LA: Minnesota Depart-ment of Health, July 1980.

*Personal Communication: Quinton J: Department of HealthServices, Sacramento, CA, December 1980.

**Personal Communication: Fox P: Deputy General Counsel,Massachusetts Dept. of Public Health. August 1982.

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Cellulose

With the energy shortage, cellulose insulation provedvery popular in that there was a ready supply of oldnewspapers and similar materials that could be used as thesource material. It is relatively inexpensive and suitable forretrofit in existing homes since it could be blown in place.

Unfortunately, cellulose proved to be a fire hazard.***Where there was overloaded plastic jacketed wiring coveredwith cellulose insulation, smouldering and eventually com-bustion occurred. Also, fires occurred when the insulationcontacted recessed lighting fixtures, especially where toohigh wattage lamps were used.

The US Consumer Product Safety Commission (CPSC)adopted an interim safety standard September 8, 1978 whichspecifies that cellulosic insulation is to be kept away fromheat sources in attics with at least three inches separationrequired from recessed lighting fixtures and other heatsources. t

Even though treated with a flame retardant, such asboric acid, cellulose insulation still presents a fire hazardwhere there is contact with recessed lighting fixtures.33 Asurvey by the US CPSC in August and September 1978estimated that three million houses had cellulose insulationinstalled between January 1976 and September 1978. About650,000 of these were estimated to have recessed lightfixtures with one-third of them candidates for attic fires.

The CPSC found that fires could occur when cellulosewas manufactured with a fire retardant to conform to astandard such as ANSI HH-1-515C. On June 15, 1978, a newmore stringent fire retardant specification was adopted forcellulose insulation that also included anti-corrosivenessprovisions. When tested with recessed light fixtures, enoughheat built up to cause a fire. The report points out, however,that there would be no hazard if the distances for separationare maintained as specified in the National Electrical Code.

Wood Chips

One incident was reported in Idaho where sawdust,used to fill wall cavities and cover ceiling, was involved in ahouse fire and firemen had to be treated for exposure to ahazardous gas. The sawdust had been subjected to destruc-tive distillation in the absence of oxygen causing a release ofcresols, and the firemen had not worn any breathing appara-tus. Subsequent investigation showed smouldering fires inthe walls would flare up when the hot spots were opened.#t

Polyurethane Rigid Board

Polyurethane is available as a foam or rigid board butbecause of great expansion of the foam during hardening, it

***Byington SJ: Remarks at Annual Meeting of Society ofInternational Cellulose Insulation Manufacturers, New Orleans,January 1978.

tKing SB: Remarks at CPSC Cellulose Home Insulation Semi-nar, Dallas, TX, October 1978.

ttPreviously cited Personal Communication, Burkhardt.

is not suitable for existing homes where walls are covered.Although flammability may be reduced by a flame retardant,the retardant may increase smoke and toxic gases in cases offire. According to a position paper published by the RockyMountain Poison Center in Colorado,27 the rigid boardshould be covered with 0.5 inch thick wallboard or equiva-lent thermal barrier to protect it from flame.

Polyurethane contains an isocyanate moiety whichwhen pyrolyzed yielded isocyanates, which are primaryirritants to the eyes, skin, and pulmonary system. They areextremely potent (especially toluene diisocyanate), and canproduce pulmonary sensitization which may result in severebronchoplastic reactions. The main concern, however, isexposure to the toxic products of thermal decomposition,primarily carbon monoxide and hydrogen cyanide which areboth fatal in low concentrations.34

Vermiculite

Vermiculite is a gravel-like hydrated silicate substancepuffed up with air. It comes in bags of loose material and isused for filling cavities in masonry walls. Due to its lowdensity, and relatively higher cost, it is not generally used forresidential ceiling insulation. No toxic effects of vermiculitehave been reported.

Mineral Wool and Fibrous Glass

"Mineral wools" have been used to indicate any fibrousglassy substance manufactured from natural rock or mineralproducts such as slag or glass.35 They are available as loosefill that can be blown into wall cavities and over ceilings, oras preformed blankets or rolls. The rolls are faced with kraftpaper, which is flammable, or aluminum foil, which shouldbe used if the facing is exposed to high temperatures or anignition source. However, mineral wool is more commonlyapplied to the fibers derived from natural rock (rock wool) orfrom slag (slag wool) whereas fibrous glass or glass fiber isapplied to the product made from synthetic glass material.Mineral wool because of its higher density, better acousticproperties and generally lower cost, finds greater use indus-trially than fibrous glass. It does contain impurities, whichmay cause health effects, and it has lesser thermal insulationproperties than fibrous glass. NIOSH reports that no firmevidence exists on which the health effects of mineral woolcan be predicted.35 Apparently, no significant or provenhealth effects from mineral wool use had been demonstrated;rather, the potential for injury is based upon animal labora-tory studies of implanted fibers of similar materials whichresulted in tumor promotion and fibrogenicity. A recentNIOSH epidemiological study36 of the mortality of rock andslag mineral wool production workers found an increase incancer deaths of the digestive system and non-malignantrespiratory diseases after 20 years of mineral wool exposureor 20-year survival after initial exposure. However, becauseof the small number of deaths reported, the increase couldnot be demonstrated to be statistically significant. Further-

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more, since such important contributory factors as thesmoking history of the workers were not assessed in themulti-factored etiology of these causes of death, the expo-sure hazard to mineral wool is only suggestive and notproved.

The health effects from fibrous glass are more demon-strative.35 Particles larger than 3.5 micron can be severelyirritating to skin, eyes, and upper respiratory tract. Removalor installation of fiber glass produces characteristic itchingand dermatitis on susceptible persons. However, there is arelatively low incidence of fibrotic lung changes, and thereare preliminary indications of slight excess mortality risk dueto non-malignant respiratory disease. NIOSH considers haz-ards of mineral wool particulates greater than that of anuisance dust but significantly less than coal dust or quartz.Recommendations of NIOSH concerning exposure to fi-brous glass are based on the fiber diameter.

There is less information on the health effects of smalldiameter fibers, i.e. less than 3.5 micron. Stanton37 et al, haddemonstrated carcinogenicity with respect to fiber dimen-sions when fibrous glass fibers were implanted in rat lungtissue, but the results of these studies cannot be extrapolatedto human exposure. Konzent1t has examined 46 referencesand found no credible evidence of malignant or chronicprogressive nonmalignant pulmonary disease resulting fromexposure to man-made vitreous fibers. He also points outthat vitreous fibers break transversally, while asbestos splitslongitudinally, and, with animal implantation studies, it isthe long, thin fibers that have been associated with carcino-genesis.

NIOSH states that observed effects are confined pri-marily to skin irritation due to mechanical actions. There isno concern over possible long-term effects from inhaledparticles, particularly those less than 3.5 micron diameter,over a long period; however, no cases of human cancer havebeen statistically associated with exposure to fibrous glass.A Japanese report reporting preliminary findings of a pneu-moconiosis developed by a woman alleged to have beenexposed to fibrous glass was subsequently discredited whenasbestos exposure was confirmed also to have been pres-ent.38

Recommendations for control include limiting airborneexposure by ventilation or respiratory protection to 3 fibersper cubic centimeter of air with fiber diameter less than 3.5micron and length greater than 10 micron, and eye and skinprotection.

Polethylene and Polyvinyl Chloride Sheeting

These materials are used as a barrier sheeting to pre-clude moisture or drafts and do not have significant thermalinsulating properties. Thermal decomposition or combustionpresents the potentially toxic exposure to carbon monoxide

ttlKonzen JL: Man-made Vitreous Fibers & Health. Paperpresented at National Workshop on Substitutes for Asbestos, spon-sored by Envitonmental Protection Agency and Consumer ProductSafety Commission, Salt Lake City, Utah. September 1980.

HEALTH EFFECTS OF ENERGY CONSERVING MATERIALS

and smoke and, in the case of polyvinyl chloride (PVC),hydrogen chloride is the principal low temperature decom-position product up to about 310°C.39 There is no evidence ofsignificant toxic amounts of the vinyl chloride monomer orthe highly toxic phosgene from thermal decomposition ofPVC fibers.40

Conclusions

Based on the information gathered in this study, thefollowing findings and conclusions are presented:

Asbestos-This is the most hazardous of all insulatingmaterials for which no level of exposure can be consideredcompletely safe. Consequently, substitute mnaterials shouldbe used whenever possible. Existing installations of friableasbestos should be removed or sealed as soon as possibleand before deterioration begins. Extreme precautionary pro-cedures are required in removal, sealing, and disposal proce-dures.

Urea-formaldehyde foam insulation-Poured in placeinsulation of this type has caused a variety of health prob-lems and is an acute inhalation problem for some people whoare or become sensitive to formaldehyde gas. The previouslycited CIIT animal study25 confirms that formaldehyde gas iscarcinogenic to rats, but no evidence of human carcinogenic-ity has been established. Off-gassing offormaldehyde occursover an extended period of time. Warning labels and noticesare ineffectual when dealing with this type of health problem.Setting standards for indoor air quality would be expensiveand difficult to enforce. Since there are reasonable substi-tutes available, the US CPSC ban of UFFI for residentialand school use may not be unreasonable.

Cellulose-The fire hazard associated with wood cellu-lose, even that which has been treated with fire retardants,indicates no preferential use or advantage for this material.

Vermiculite-This material has no known health prob-lems but its use is limited by cost and density.

Polyurethane-The potential for exposure to the highlytoxic thermal decomposition products bears caution in anyrecommendation.

Mineral Wool and Glass Fibers-If a flammable vaporbarrier is used as the facing, these materials should becovered with gypsum board or similar protective material.Although precautions may have to be taken to avoid eye,skin and respiratory irritation from glass fibers, the generic"mineral wools" are the material of choice from the stand-point of health hazards, flammability and fire protection, andcost. Generally, the rock or slag wool product is favoredindustrially whereas glass fiber finds greater, though notexclusive, application in residences.

REFERENCES1. US Comptroller General: Indoor Air Pollution: An Emerging

Health Problem. A Report to the Congress of the United States.September 24, 1980.

2. HUD/DOE: The Energy-Wise Home Buyer: A Guide to Select-ing an Energy Efficient Home. US Department of Housing andUrban Development in cooperation with the US Department ofEnergy. Washington, DC: HUD/DOE March 1979.

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3. HUD: Insulation Fact Sheet FS-3, Pub. No. HUD-PDR-492-17.Washington, DC: US Department of Housing and Urban Devel-opment.

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ACKNOWLEDGMENTAn earlier version of this paper was presented at the Annual

Meeting of the American Association for the Advancement ofScience, Toronto, Canada, January 1981.

1983 Public Health/Community Health Nursing Leadership Institute"Transforming Realities of Practice," the third annual public health nursing leadership institute

will be held June 12-15, 1983 at the Earle Brown Continuing Education Center, St. Paul Campus,University of Minnesota, Minneapolis.

For further information, contact Continuing Nursing Education, University of Minnesota, 107Armory Bldg., 15 Church Street SE, Minneapolis, MN 55455. Telephone 612/373-5831.

690 AJPH June 1983, Vol. 73, No. 6