Allergic respiratory disease and fungal remediation in a building in a subtropical climate.

An outbreak of allergic respiratory disease occurred in a new building that was characterized from initial occupancy by the presence of extensive visible mold (especially Aspergillus versicolor) on interior surfaces. Epidemiological study of the occupants of both the affected building and a comparison neighboring structure indicated high rates of respiratory and other symptoms among persons working in the affected building. Subsequent clinical evaluations of some persons occupying the building for up to five years identified several cases of building-related allergic respiratory disease, including asthma and hypersensitivity pneumonitis. Based on these findings, the building was evacuated before remediation began. The mycological goal of the three-year building restoration project was to reduce concentration of non-phylloplane fungi such as A. versicolor to the lowest feasible level. All visibly colonized materials in the building were discarded and all fine dust on interior surfaces was removed by vacuuming and/or damp wiping. A medical surveillance program utilizing serial self-reported questionnaires and readily available clinical evaluations was designed to monitor the health of building occupants after re-entry. Symptom rates just prior to building reentry were substantially lower than those found before evacuation and have remained unchanged after re-occupancy was completed. No new or recrudescent cases of illness are known to have occurred after building re-entry.

Cross-sectional follow-up of a flu-like respiratory illness among fiberglass manufacturing employees: endotoxin exposure associated with two distinct sequelae.

Over a period of 10 years, employees in a manufacturing plant experienced sporadic flu-like episodes after work in a basement containing a recirculated washwater mist. We report a cross-sectional study to define the flu-like illness and bioaerosol exposures. High concentrations of gram-negative bacteria (GNB) (> 10(7) cfu/ml) and endotoxin (range 34-46 micrograms/ml) were found in the water. Mist contained > 10(3) cfu/m3 of GNB, and endotoxin up to 13,900 to 27,800 ng/m3. Few fungi and thermotolerant Bacillus species and no Actinomycetes, Legionella species, or amoeba were found in washwater. Airborne levels of fungi were of the same species and magnitudes as outdoor samples. Subjects volunteered (n = 28) because of a history of flu-like symptoms or were randomly selected (n = 102) from workers with and without current exposure to the basement. No acute cases were examined. Cases did not fulfill criteria for hypersensitivity pneumonitis (HP) and high levels of IgG antibodies to water-borne antigens were not observed. However, among 20 subjects indicating a history of severe flu-like episodes (severe basement flu, SBF), diffusion capacity (DLCO) was significantly lower (p = 0.015) than among other workers. The prevalence of SBF was independent of smoking. Cases occurred in clusters, and SBF was more common among workers with intermittent exposure to the basement (19 cases) than with daily exposure (1 case). These findings suggest that SBF and associated chronically depressed DLCO resulted from toxic injury following high-level endotoxin exposure. Asthma was prevalent in the study population, particularly among employees with daily, rather than intermittent, exposure to endotoxin-containing mist (odds ratio 6.7, p = 0.02). Thus, endotoxin exposure in this study was associated with two distinct sequelae depending on the temporal pattern of exposure.

Practical aspects of sampling for organic dusts and microorganisms.

Air sampling for organic dusts and microorganisms was carried out in silos when moldy silage was discarded through the discharge chute. Concentrations of respirable dust and airborne viable microorganisms exceeded 20 mg/m3 and 1 x 10(9)/m3, respectively, when dry silage was removed from silos. Much lower concentrations of dust and microorganisms were present when wet silage was discarded. Impinger and filter cassette samplers were equally effective in collecting the hardy spores present in silage dusts.

Role of ventilation in the causation of building-associated illnesses.

The objective of this article is to provide the reader with a basic knowledge of the operation of heating, ventilation, and air-conditioning (HVAC) systems and to explain why many systems do not perform correctly. The flow of air through a typical HVAC system is described, and the correlation between system components and their potential to affect indoor air quality is addressed.

An outbreak of recurrent acute and chronic hypersensitivity pneumonitis in office workers.

Three episodes of an acute, flu-like illness, one studied in detail, were associated with manipulations on the central air handling system of an office building in Tennessee in the summer and early fall of 1981. Symptoms were compatible with acute hypersensitivity pneumonitis, although the time of onset revealed a biphasic epidemic curve. Breathing air not supplied through the central air handling system protected against disease. Ill persons had significantly more precipitins to agents cultured from the building than did controls. Symptoms suggestive of chronic hypersensitivity pneumonitis were also found. Chronic disease was associated with the presence of humidifiers at home, asthma, and longer work in the building. Acute disease occurred less frequently in smokers and persons who had previously worked in the building before 1976. Persons with acute disease were more likely to have chronic disease. No single etiologic agent could be identified. Because of difficulties with demonstrating safety for reoccupancy, the building was vacated and remains empty at this time.

The distribution of gram negative bacteria and endotoxin on raw cotton components.

The botanical composition of representative raw cottons from seven different growing regions was determined by manual removal and identification of all trash components greater than 50 micron in size. The number of gram negative bacteria (GNB) and the amount of endotoxin present in each of the separated raw cotton components were quantified. Low middling cotton contained significantly more bract-leaf trash than that found in higher quality cottons such as those in the middling grade division. Significantly more GNB and endotoxin were found in botanical trash components as well as lint of raw cotton derived from the southwest and southeast growing regions as compared to similar botanical components from far west cottons. For representative raw cottons from the 1980 USA crop we determined that 67% of the GNB and 89% of the endotoxin resided on white lint itself, from which all particulate larger than 50 micron in size had been removed manually.

Effects of a cotton bract extract on guinea pig isolated airway smooth muscle.

The effects of a water extract of cotton bracts (CBE) on guinea pig isolated trachealis smooth muscle was studied. The ability of CBE to evoke tension responses, to modify tissue reactivity to excitatory and inhibitory agents, and to modify electric field stimulation-induced neurogenic responses was evaluated. CBE caused contraction in low concentrations, which were not mediated by histamine H1-, muscarinic, or 5-hydroxytryptamine (5-HT) receptors, and caused relaxation in high concentrations. In the presence of CBE, the maximum contractile response to 5-HT and the sensitivity to KCl were reduced. The maximum relaxation responses and sensitivities to adenosine and ATP were increased by CBE. In contrast, contractile responses to histamine and methacholine and relaxation responses to isoproterenol were unaffected. Neurogenic cholinergic excitatory responses and neurogenic adrenergic responses did not appear to be affected by CBE. However, the relaxant effect of nonadrenergic inhibitory nerve stimulation was increased in the presence of CBE. These findings differ from previous ones observed in our laboratory for dog isolated trachealis smooth muscle preparations, which indicates that the effects of CBE in isolated airways is species-dependent. Virtually all of the contractile activity of CBE was dialyzable (molecular weight less than 14,000) and retained in ashed samples. Inorganic constituents may contribute to the spasmogenic activity of CBE.

Pulmonary disease associated with cafeteria flooding.

An illness among office workers, consisting of cough, fever, chills, muscle aches, and chest tightness was associated with water leaks from a cafeteria. Mean single breath carbon-monoxide diffusing capacity (DLCO) of cases differed significantly from that of non-cases. There was a significant decrease in the percent of predicted DLCO with increasing number of symptoms. Testing for precipitating antibodies to microbial agents found in the building revealed no differences between cases and non-cases. DLCO is an appropriate cross-sectional instrument for field investigations of building-associated respiratory disease.

Medical and industrial hygiene characterization of the cotton waste utilization industry.

We studied 260 workers in the cotton waste utilization industry and 310 "blue-collar" control workers from nondusty industries in the same geographic area of the United States by respiratory symptom questionnaire and by pre- and postshift spirometry. We excluded 75 cotton workers and 75 control workers from statistical analysis because of prior hazardous occupational exposures. Plant-wide, 8-hour time-weighted average exposures ranged from 0.28 mg/m3 to 7.80 mg/m3. The overall prevalence of symptoms compatible with byssinosis was 5.9% in cotton workers and 4.7% in the controls. Cotton workers with less than 2 years of employment had a significantly greater prevalence of bronchitis than their control counterparts. The cotton workers with 2 years or more of employment had significantly greater prevalences of bronchitis, shift decrement in forced expiratory volume in 1 second (FEV1) of greater than or equal to 10%, and FEV1/FEV1-predicted less than 80%, than their control counterparts. Regression analysis showed that for matched cotton and control workers, the percentage decrement in FEV1 over the shift was significantly greater for cotton workers; and that in all cotton workers, longevity in industry had a negative effect on the before-shift forced vital capacity (FVC). This study suggests that there are both acute and chronic effects of cotton exposure in the cotton waste utilization industry.

Vegetable ingredients of dusts in textile and nontextile cotton industries.

The objective was to determine if garnetting and raw cotton dusts differed in botanical composition. Estimates of dust composition were based on the contents of gross trash in cotton raw materials and the potential of each gross trash component to be converted into less than 10 mum particulate by a laboratory abrasion test. All types of garnetting dusts are predicted to contain a lower percent content of leaflike material than raw cotton dust. Garnetting dusts arising from linter-polyester blends are estimated to contain only 20 to 25 percent of the concentration of leaflike ingredients predicted to be present in raw cotton dusts. The low prevalence of byssinosis reported in the garnetting industry may be explained, in part, by the relatively low percent content of leaflike particulate in this cotton dust.

Capitate hairs on cotton textile wastes.

Bract and leaf samples from growing cotton plants and from cotton textile wastes were examined by scanning electron microscopy to determine if intact capitate hairs are important components fo raw cotton wastes. The density of capitate hairs on bract and leaf fragments in raw cotton was similar to that found on bracts and leaves from greenhouse and field collections. A bale of strict low middling raw cotton contains between 1.23 an 2.54 X 10(8) capitate hairs of bract origin alone. Capitate hairs could be important components of cotton textile wastes because of their abundance and because they contain chemicals that may be involved in the cause of respiratory disease in textile workers.

Botanically what is raw cotton dust?

The objective of this study was to determine the specific botanical ingredients present in respirable raw cotton dust. Significant differences in content of gross leaflike (bractcontaining) trash were found between several grade divisions of raw cottons. For example, higher grades of raw cotton (strict low middling = SLM) contained less leaflike trash than lower grade cottons (low middling = LM). The potential for production of fine particulate from botanical trash materials plus lint and linters was determined in the laboratory by an abrasive milling test. Bract and wood fragments were the most friable of all plant materials found in raw cottons whereas seed meat, lint, linters and seed coat were the least friable. Respirable (10 less than 10 micrometers) raw cotton dusts associated with the processing of middling, SLM and LM raw cottons were predicted to contain the following % weight composition of specific vegetable ingredients: leaflike = 70--72%, stem = 13--18%, bark = 3--8%, exocarp-mesocarp = 3.6%, endocarp = 1--2% and seed = 0.5--2%. Bract is the most abundant component in respirable raw cotton dust.

Evaluation of a fluorescent dust tracer technique in cotton ginning.

A technique employing a fluorescent tracer for following the break-up and dispersion of cotton trash has been developed. Senescent cotton leaves were treated with a fluorescent dye, pulverized to match the same particle size distribution as naturally occurring leaf in raw seed cotton and uniformly incorporated into the seed cotton mass prior to processing in a saw-type micro-gin. A control lot was similarly processed, excluding any dye. Airborne samples collected from the major fugitive dust emission points by standard techniques, macro trash samples collected from four locations, and the final condensed lint product clearly show that the use of such tracers is not only feasible but highly useful in determining the locations where respirable dust is emitted. From the fraction of labelled tracer material found at any site, the relative amounts of both total and respirable dust emissions of that plant component can be estimated from the known masses of dyed material added to a given mass of seed cotton. Estimates of the relative severity of fugitive dust emissions from various processing steps in a cotton gin are presented based on vertical elutriator, high volume and multistage cascade impactor sampler data.

Effect of chemical defoliation on leaf and bract content in raw cotton.

Chemical defoliants are applied to about 40% of the U.S. Cotton acreage as a harvest-aid practice prior to machine picking. Raw cottons derived from defoliated and nondefoliated fields were examined for content of bract and leaf trash Chemical defoliation lowered, but did not remove, leaf as a major trash component. The content of bract was unaffected by this harvest-aid practice. The histamine content in green leaf trash was 10X that found in nongreen leaf trash.

Occupational dust exposures in West Texas cotton gins.

Total and elutriated dust concentrations were measured by four methods for typical ginning situations. Total and elutriated levels were 0.73 and 0.47 and 0.59 and 0.26 mg/m3 per bale/hr by the gin stands and bale press, respectively. Limited data show the corresponding mass media diameters are 9.2-14.8 and 9.6-18.5 micrometer.

A comparison of cotton dust sampling techniques.

The standard high volume sampler, multistage cascade impactor, and modified vertical elutriators were evaluated for total cotton dust sampling. The effects of changes in performance parameters is reported. Mass median dust diameter found in four textile operations for several cotton grades are reported.