Effect Of Cotton Dust Exposure On Respiratory Health Outcomes Among Textile Workers.

BACKGROUND: Cotton dust is generated during various textile manufacturing processes. Only a few studies from Pakistan assessed cotton dust exposure and explored the relationship of duration of work in the textile industry with respiratory health outcomes. We aimed to assess cotton dust exposure and its association with lung function and respiratory symptoms among textile workers in Pakistan. METHODS: We report findings from the baseline survey of the larger study, MultiTex, among 498 adult male textile workers from six mills conducted between October 2015-March 2016 in Karachi, Pakistan. Data collection included the use of standardized questionnaires; spirometry, and area dust measurements through UCB-PATS. Multivariable logistic and linear regression models were developed to assess the association of risk factors with respiratory symptoms and illnesses. RESULTS: We found the mean age of workers to be 32.5 (±10) years; around 25% were illiterate. The prevalence of COPD, asthma, and byssinosis was 10%, 17%, and 2%, respectively. The median cotton dust exposure was 0.33 mg/m3 (IQR: 0.12-0.76). Increased duration of work among non-smokers was associated with a decline in lung function, FVC (-245 ml; 95% CI: -385.71, -104.89) and FEV1 (-200 ml; 95% CI: -328.71, -841.1). Workers with certain job titles (machine operators, helpers, and jobbers), those with greater duration of work, and higher dust exposure, were more likely to report respiratory symptoms and illnesses. CONCLUSIONS: We report a high prevalence of asthma and COPD and a low prevalence of byssinosis. Cotton dust exposure and duration of employment were associated with respiratory health outcomes. Our findings highlight the need for preventive interventions in the textile industry in Pakistan.

Byssinosis and lung health among cotton textile workers: baseline findings of the MultiTex trial in Karachi, Pakistan.

OBJECTIVES: To assess the association of exposure in cotton mills in Karachi with different definitions of byssinosis and lung health. METHODS: This cross-sectional survey took place between June 2019 and October 2020 among 2031 workers across 38 spinning and weaving mills in Karachi. Data collection involved questionnaire-based interviews, spirometry and measurements of personal exposure to inhalable dust. Byssinosis was defined using both WHO symptoms-based (work-related chest tightness), and Schilling's criteria (symptoms with decreased forced expiratory volume in 1 s (FEV1). Values of FEV1/forced vital capacity ratio below the lower limit of normality on postbronchodilator test were considered as 'chronic airflow obstruction' (CAO). RESULTS: 56% of participants had at least one respiratory symptom, while 43% had shortness of breath (grade 1). Prevalence of byssinosis according to WHO criteria was 3%, it was 4% according to Schilling's criteria, and likewise for CAO. We found low inhalable dust exposures (geometric mean: 610 µg/m3). Cigarette smoking (≥3.5 pack-years), increasing duration of employment in the textile industry and work in the spinning section were important factors found to be associated with several respiratory outcomes. CONCLUSION: We found a high prevalence of respiratory symptoms but a low prevalence of byssinosis. Most respiratory outcomes were associated with duration of employment in textile industry. We have discussed the challenges faced in using current, standard guidelines for identifying byssinosis.

A very unusual case of interstitial lung disease.

Cotton dust exposure has been implicated in causing diseases like byssinosis and obstructive airway diseases like COPD and asthma. Long-term exposure to cotton dust causing interstitial lung disease and pulmonary fibrosis has been sparsely reported in the literature. Here, we report a case of an individual with long-term cotton dust exposure who presented with typical symptoms of interstitial lung disease and was managed conservatively.

COVID 19 - Possible interrelations with respiratory comorbidities caused by occupational exposure to various hazardous bioaerosols. Part I. Occurrence, epidemiology and presumed origin of the pandemic.

The occupational bioaerosols containing viruses, bacteria, fungi, microbial toxins and plant or animal particles, may evoke infectious, allergic or immunotoxic diseases which may co-exist as comorbidities with COVID-19 and exacerbate the course of disease. They include hypersensitivity pneumonitis (HP) caused mostly by bacteria, fungi, and particles containing animal proteins, and immunotoxic diseases such as organic dust toxic syndrome (ODTS) and byssinosis, caused mostly by bacterial and fungal toxins. The two most probable scenarios of possible interrelations between these three comorbidities (CM) and COVID-19 are: 1) 'Triggering' - when infection with SARS-CoV-2 triggers severe CM after bioaerosol exposure; 2) 'Reverse triggering' when exposure to bioaerosol exacerbates a symptomless or mild course of COVID-19, and evokes a severe disease. The occupations mostly endangered by COVID-19 as the result of exposure to SARS-CoV-2 bioaerosol, or to other bioaerosols which may exacerbate this disease, include: health care workers, social workers, breeders of fur animals, slaughterhouse workers, workers engaged in the processing and selling of seafood, and probably also agricultural workers, mainly in the developing countries. The authors present a hypothesis for the origin of the present pandemic. It assumes that a mild form of the present SARS-CoV-2 that is supposedly circulating among the Chinese population in the eastern part of the country, mutated under the influence of as yet unknown factor(s) present in the Chinese seafood markets, probably component(s) of bioaerosols, into the virulent and highly contagious form, known as the present SARS-CoV-2, under a scenario similar to that the authors have named 'Reverse triggering'.

MultiTex RCT - a multifaceted intervention package for protection against cotton dust exposure among textile workers - a cluster randomized controlled trial in Pakistan: study protocol.

BACKGROUND: In the Pakistani textile industry the prevalence of workplace respiratory illnesses, including byssinosis, is high. The MultiTex RCT study aims to determine the effectiveness of a multifaceted intervention package in reducing dust levels in cotton mills, decreasing the frequency of respiratory symptoms among cotton textile workers, and improving their lung function. METHODS/DESIGN: We will conduct a cluster-randomized controlled trial at 28 textile mills in Karachi. The intervention will comprise: training in occupational health for all workers and managers reinforced by regular refresher sessions; the formation of workplace committees to draw up, agree and promote a health and safety plan that includes wet mopping, safe disposal of cotton dust, and the use of simple face-masks, as well as further publicity about the risks from cotton dust; and provision of adequate supplies of face-masks to support the health and safety plan. Participating mills will be randomized to intervention and control arms following a baseline survey. The impact of the intervention will be determined through follow-up surveys conducted at 3, 12 and 18 months. Data collection in the surveys will include spirometry, questionnaire-based interviews and cotton-dust measurements. DISCUSSION: If successful, the study may pave the way for simple, low-cost interventions that can help reduce cotton-dust levels in textile mills, and improve the respiratory health of textile workers in developing countries such as Pakistan. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT03738202. Registered on 12 November 2018.

Byssinosis and tuberculosis amongst "home-based" powerloom workers in Madhya Pradesh State, India.

BACKGROUND: Byssinosis is an occupational lung disease observed among workers exposed to cotton, flax, and hemp dust. The severity and extent of Byssinosis are well recognised in the high-income countries and control measures have been implemented to prevent the disease. In India, there are conflicting evidence on burden estimation of the disease, followed by inadequate prevention and control of Byssinosis. DESIGN/METHODS: We did a cross-sectional study to assess the prevalence of Byssinosis in "home-based" power-loom workers in Mominpura, an administrative ward of Burhanpur Municipality with 2800 population in the state of Madhya Pradesh, India. 290 adults working from "home-based" power loom units were randomly selected, profiled and screened for Byssinosis like symptoms with the help of a semi-structured questionnaire and simple hand-held peak expiratory flow monitor. For epidemiological purposes the symptoms were classified based on Schilling's classification. Chest x-rays were done for selected subjects. Sputum smear microscopy for detecting TB was done for those who had Byssinosis like symptoms. RESULTS: Prevalence of Byssinosis among "home based" powerloom workers was found to be 98% [n = 283, 95 CI (95.65-98.96)]. Peak expiratory flow rate (PEFR) was reduced in 44% (n = 124), of which 81 (29%) had more than 50% PEFR reduction, and of these, 69 (29%) were in early stage of Byssinosis (Grade 0.5). 11% of study participants who had Byssinosis like symptoms, also had TB. CONCLUSIONS: Byssinosis is highly prevalent in "home-based" power loom units in Madhya Pradesh. Adequate advocacy on awareness and prevention; prompt diagnosis and linkages to treatment services in "home-based" power loom units are urgently required to address Byssinosis at an early disease stage.

Environmental Causes of Asthma.

Environmental factors which cause asthma are those that induce airway inflammation with eosinophils (more common) or neutrophils along with airway hyperresponsiveness (AHR). The most common of these (indeed the most common cause of asthma) are IgE-mediated inhalant allergen exposures. Allergen-induced AHR and inflammation are both associated with the allergen-induced late asthmatic response (LAR). Although allergens were previously recognized only as causes of symptoms and bronchoconstriction in asthmatics, we now appreciate them as causes of the fundamental pathophysiologic features of asthma. Low-molecular-weight chemical sensitizers, causes of occupational asthma, also cause asthma in a manner analogous to allergen. Acute irritant-induced asthma (reactive airways dysfunction syndrome) following a very heavy irritant exposure and chronic irritant-induced asthma following repeated high exposures can also induce persistent or permanent changes (inflammation and AHR) consistent with asthma. Textile dust exposure produces a different form of airway disease (byssinosis) which is less frequently observed currently. Environmental exposure to tobacco smoke facilitates the development of asthma in children. Personal smoking and environmental air pollution have an inconsistent and likely generally small effect in causing asthma.

Byssinosis and COPD rates among factory workers manufacturing hemp and jute.

OBJECTIVES: Prior studies have been performed on cotton textile plants throughout the world. This study was planned to identify the rate of byssinosis and chronic obstructive pulmonary disease (COPD) in hemp and jute workers and those who worked with both of them. MATERIAL AND METHODS: The study was realized in a factory which consecutively processed hemp and jute. The study enrollment included 266 people, 164 of whom were active workers and 102 were retired. A questionnaire, plain chest X-rays, physical examination and pulmonary function tests were performed. Dust levels were measured in various sections of the factory during 8 h work shifts. Endotoxin levels of various quality hemp fibers and dusts were measured. RESULTS: The rate of byssinosis (28.2%) was higher among the workers that who exposed to both jute and hemp dust. The frequency of chronic bronchitis in retired workers who previously smoked was higher (20%) as compared to currently smoking workers (17%). High dust levels were measured in some parts of the factory (mean (M) = 2.69 mg/m3). Working in dense dust areas, active smoking, being older than 40 years of age, being an ex-smoker, and working in the factory for a period exceeding 15 years were significantly associated with bronchitis and emphysema development. High endotoxin levels were determined for fine hemp dust (605 EU/mg), coarse hemp dust (336 EU/mg) and poor quality hemp fibers (114 EU/mg), whereas in fresh hemp stalks the level of endotoxin was determined to be lower (0.27 EU/mg). CONCLUSIONS: Because of high exposures to jute and hemp dusts that are associated with high byssinosis rates, personal protection and environmental hygiene is crucial to prevention of byssinosis.

Metal fume fever and polymer fume fever.

INTRODUCTION: Inhalational exposure to metal-containing fumes generated by welding and related processes may result in the development of the clinical syndrome known as "metal fume fever." Polymer fume fever is a separate and distinct but related disorder that has been associated with inhalational exposure to specific fluorinated polymer products, such as polytetrafluoroethylene or Teflon(®). We undertook a review of the peer-reviewed medical literature as it relates to these two disease entities in order to describe their epidemiology, pathophysiology, clinical presentation, diagnosis, treatment, prevention, and prognosis. METHODOLOGY: We performed a search of the PubMed ( www.pubmed.com ) and Ovid MEDLINE (ovidsp.tx.ovid.com) databases for keywords "metal fume fever," "polymer fume fever," and "fume fever," covering the period 1946 to September 2014, which resulted in a total of 141 citations. Limiting the search to articles published in the English language yielded 115 citations. These 115 articles were manually reviewed for relevance. In addition, the reference lists in each article retrieved were reviewed for additional relevant references. This left 48 relevant citations. EPIDEMIOLOGY: Metal fume fever occurs most commonly as an occupational disease in individuals who perform welding and other metal-joining activities for a living. It is estimated that 1,500-2,500 cases of metal fume fever occur annually in the United States. Polymer fume fever was initially identified as an occupational disease but increased regulations have resulted in decreased incidence in the occupational setting. Overheating of Teflon(®)-coated cookware is one of the more common mechanisms for exposure. PATHOPHYSIOLOGY: While the precise pathophysiology associated with the development of metal fume fever is yet to be elucidated, suggested pathophysiologic mechanisms include pro-inflammatory cytokine release, neutrophil activation, and oxygen radical formation. The pathophysiologic mechanism for polymer fume fever has not been definitively elucidated but may involve similar mechanisms to those proposed for metal fume fever. CLINICAL PRESENTATION: Metal fume fever typically presents with generally non-specific complaints including influenza-like symptoms, fever, shaking chills, arthalgias, myalgias, headache, and malaise. Onset of symptoms typically occurs 4-10 h following the exposure to metal-containing fumes. While metal fume fever is typically benign and self-limited, severe cases of the disease have been reported. In patients with ongoing metal fume exposure over the course of a workweek, tachyphylaxis occurs resulting in improvement in symptoms over the course of the workweek and maximal symptoms occurring after an exposure-free period such as a weekend. The clinical presentation of polymer fume fever is indistinguishable from metal fume fever, with an exposure history being necessary to distinguish the two entities. DIAGNOSIS: Chest radiographs are typically normal in cases of metal fume fever and polymer fume fever; however, mild vascular congestion may be demonstrated and severe cases may feature diffuse patchy infiltrates. Laboratory studies are typically not necessary but may demonstrate leukocytosis with leftward shift or an elevated erythrocyte sedimentation rate. TREATMENT: The primary treatment for both metal fume fever and polymer fume fever is supportive and directed at symptom relief. Oral hydration, rest, and the use of antipyretics and anti-inflammatory medications (e.g., non-steroidal anti-inflammatory drugs and aspirin) are recommended. A careful workplace exposure assessment analysis conducted by an occupational medicine specialist or clinical toxicologist in concert with a qualified industrial hygienist should be performed. PREVENTION: A careful workplace exposure assessment including measurement of ambient zinc and other metal (e.g., chrome, nickel, copper and manganese) fume concentrations or concentrations of fluorocarbon polymer decomposition products at different locations within the workplace should be performed. PROGNOSIS: Metal fume fever is typically a benign and self-limited disease entity that resolves over 12-48 h following cessation of exposure. CONCLUSIONS: Metal and polymer fume fevers generally follow a benign course with spontaneous resolution of symptoms, though both have the potential to be serious, especially in those with significant preexisting cardiorespiratory disease.

A large scale gene-centric association study of lung function in newly-hired female cotton textile workers with endotoxin exposure.

BACKGROUND: Occupational exposure to endotoxin is associated with decrements in pulmonary function, but how much variation in this association is explained by genetic variants is not well understood. OBJECTIVE: We aimed to identify single nucleotide polymorphisms (SNPs) that are associated with the rate of forced expiratory volume in one second (FEV1) decline by a large scale genetic association study in newly-hired healthy young female cotton textile workers. METHODS: DNA samples were genotyped using the Illumina Human CVD BeadChip. Change rate in FEV1 was modeled as a function of each SNP genotype in linear regression model with covariate adjustment. We controlled the type 1 error in study-wide level by permutation method. The false discovery rate (FDR) and the family-wise error rate (FWER) were set to be 0.10 and 0.15 respectively. RESULTS: Two SNPs were found to be significant (P<6.29×10(-5)), including rs1910047 (P = 3.07×10(-5), FDR = 0.0778) and rs9469089 (P = 6.19×10(-5), FDR = 0.0967), as well as other eight suggestive (P<5×10(-4)) associated SNPs. Gene-gene and gene-environment interactions were also observed, such as rs1910047 and rs1049970 (P = 0.0418, FDR = 0.0895); rs9469089 and age (P = 0.0161, FDR = 0.0264). Genetic risk score analysis showed that the more risk loci the subjects carried, the larger the rate of FEV1 decline occurred (P trend = 3.01×10(-18)). However, the association was different among age subgroups (P = 7.11×10(-6)) and endotoxin subgroups (P = 1.08×10(-2)). Functional network analysis illustrates potential biological connections of all interacted genes. CONCLUSIONS: Genetic variants together with environmental factors interact to affect the rate of FEV1 decline in cotton textile workers.

Byssinosis: as seen in cotton spinning mill workers of Karachi.

OBJECTIVE: To identify Byssinosis in cotton spinning mill workers, probable associations of disease with factors such as different work areas, safety gadget usage and overtime and to ascertain proportions of byssinosis to accidental injuries. METHODS: This study was conducted in a spinning mill of Karachi in June 2006. Mill workers who had worked for a period of minimum 5 years were selected. A sample size of 83 conveniently selected workers participated in the research study. Data collection was done via questionnaire, and pulmonary function tests. RESULTS: The mean age of the sample was 30 +/- 6.9 years. Of all the workers 72% used safety gadgets (masks) while working and 50% availed overtime. Smokers amounted to 31% of the total subjects. Around 35% workers complained of having respiratory ailments of which 19% (16 workers) closely matched byssinotic symptoms. Pulmonary Function Tests (PFTs) confirmed 13 of 16 workers to be byssinotics, with the remaining being labeled as Probables. The overall proportion of Byssinotics in the mill was 19.28% (95% C.I. 11-27) and that of accidental injuries was 22.9%. The association of byssinosis with respect to work areas was significantly high in Ring area (O.R. = 2.04) followed by carding (O.R. = 1.3). The association of byssinosis was also high in workers who did not use safety gadgets, e.g. dust masks (O.R = 4.89) and in people who worked overtime (O.R. = 1.82). Associations with respect to duration of employment and smoking could not yield significant results. CONCLUSION: Results indicate a very high probability of association of disease to non-usage of safety gadgets and overtime working. Studies comprising of a greater sample size would show precisely the overall prevalence of the disease.

The measurement and health impact of endotoxin contamination in organic dusts from multiple sources: focus on the cotton industry.

Endotoxin is derived from Gram-negative bacterial membranes, and its inflammatory effects following inhalation are well characterized. The significance of this fact becomes apparent when the wide-ranging environments containing high levels of this microbial product are considered. Endotoxin is present in numerous industrial environments, especially where organic fibers are processed. Microbial contamination of these fibers mainly occurs at the agricultural stage. Materials such as flax and hemp are affected in this way, but the most important product in this context is cotton, from which chronic dust inhalation causes the disease byssinosis. Despite the fact that endotoxin constitutes a significant threat to public health, there are currently no occupational exposure limits for this toxicant. This communication describes the toxicology of endotoxin, and its role in inhalation-induced disease, focusing on measurement of airborne endotoxin in the occupational and domestic environments using the Limulus amebocyte lysate (LAL) enzyme assay. Following the success of the LAL assay for measuring endotoxin in dusts, our laboratory has examined its application to aqueous washes from cotton fibers. Reproducibility of the results was high, and data are presented displaying levels of endotoxin contamination in fibers from different cotton producing countries. Hence, worldwide comparison of industrial endotoxin concentrations can be readily made using this test. It would be highly desirable if the performance of the LAL assay facilitated introduction of industrial endotoxin safety limits, and in spite of minor surmountable shortcomings, the test is accurate, reliable, and well field-tested, so its continued widespread use may achieve this goal.

Airborne endotoxin and its relationship to pulmonary function among workers in an Indian jute mill.

Air samples from various processing areas of an Indian jute mill were examined for endotoxin. The authors assessed work-related respiratory symptoms and pulmonary function changes in the dust-exposed workers from the different processing areas using a standard questionnaire and spirometry. Endotoxin was estimated in water extract of jute dust from 3 milling areas, and in outside air, by the Limulus amebocyte lysate gel clot technique. The batching, spinning, and weaving areas of the jute mill showed endotoxin levels of 0.22-4.42 microg/m3, 0.04-1.47 microg/m3, and 0.01-0.07 microg/m3, respectively, values similar to those found in Indian cotton mills. Respiratory morbidities among the workers included typical byssinotic symptoms, along with acute changes in postshift forced expiratory volume in 1 s (FEV1.0) (31.8%). Results of this study demonstrated that increased exposure to bacterial endotoxin in airborne dust is related to byssinotic symptoms among Indian jute mill workers. Findings were similar to those reported previously for workers in the cotton, flax, and hemp industries.

Respiratory symptoms and cotton dust exposure; results of a 15 year follow up observation.

AIMS: To determine chronic effects of long term exposure to cotton dust and endotoxin on incidence of respiratory symptoms and the effect of cessation of exposure. METHODS: Respiratory health in 429 Chinese cotton textile workers (study group) and 449 silk textile workers (control group) was followed prospectively from 1981 to 1996. Byssinosis, chest tightness, and non-specific respiratory symptoms were assessed by means of identical standardised questionnaires at four time points. Exposures to cotton dust and endotoxin were estimated using area samples collected at each survey. Incidence and persistence of symptoms were examined in relation to cumulative exposure and exposure cessation using generalised estimating equations (GEE). RESULTS: Among cotton workers, the cumulative incidence of byssinosis and chest tightness was 24% and 23%, respectively, and was significantly more common in smokers than in non-smokers. A high proportion of symptoms was found to be intermittent, rather than persistent. Among silk workers, no typical byssinosis was identified; the incidence of chest tightness was 10%. Chronic bronchitis, cough, and dyspnoea were more common and persistent in the cotton group than in the silk group. Significantly lower odds ratios for symptoms were observed in cotton workers who left the cotton mills; risk was also related to years since last worked. Multivariate analysis indicated a trend for higher cumulative exposure to endotoxin in relation to a higher risk for byssinosis. CONCLUSION: Chronic exposure to cotton dust is related to both work specific and non-specific respiratory symptoms. Byssinosis is more strongly associated with exposure to endotoxin than to dust. Cessation of exposure may improve the respiratory health of cotton textile workers; the improvement appears to increase with time since last exposure.

Respiratory effects of long-term exposure to cotton dust.

Traditionally, the concept of cotton dust-related disease focused on acute airway responses. A possible connection of long-term exposure to cotton dust with chronic obstructive airway disease was not addressed until the past two decades. This review summarizes the latest findings relevant to this topic that were observed from longitudinal cohort studies and discusses the relation between acute airway responses and chronic losses of lung function.

A longitudinal observation of early pulmonary responses to cotton dust.

AIMS: To examine early adverse pulmonary effects of exposure to cotton dust, and to identify potential risk factors, including atopy for pulmonary responses to cotton dust. METHODS: Spirometry, methacholine challenge testing, and questionnaire; performed among 101 non-smoking newly hired textile workers at baseline (prior to starting work), and at 3, 12, and 18 months after starting work. Concentrations of airborne cotton dust in various work areas were measured at each follow up survey using vertical elutriators. RESULTS: The incidence of non-specific respiratory symptoms was 8% at three months, then diminished afterwards. Substantial acute cross shift drops in FEV(1) at each follow up survey, and longitudinal declines in FVC and FEV(1) after 12 months of exposure were observed. Airway responsiveness to methacholine increased with follow up time, and was more pronounced among atopics. Increasing airway responsiveness was strongly correlated with cross shift drops in FEV(1). In addition, one or more respiratory symptoms at three months was significantly, and pre-existing atopy marginally significantly, associated with cross shift drops in FEV(1) after adjusting for other covariates and confounders. CONCLUSION: Results suggest that non-specific respiratory symptoms, decreasing lung function, and increasing airway responsiveness are early pulmonary responses to cotton dust. In addition, the occurrence of respiratory symptoms and increasing airway responsiveness, as well as atopy, may be important predictors for acute changes in lung function among cotton textile workers.

Respiratory symptoms, lung function and cell surface markers in a group of hemp fiber processors.

BACKGROUND: Hemp dust exposure is associated with byssinosis and accelerated lung loss in longitudinal studies. The immunological changes associated with hemp dust exposure are less well understood. METHODS: We studied a small group of current male hemp processors with a mean age of 43 years. Questionnaire data, lung function, serial FEV(1) and blood were collected from all workers. RESULTS: In total, seven workers (64%) complained of at least one respiratory symptom (one with byssinosis). The mean percentage predicted FEV(1) was 91.5, FVC 97.7, PEF 92.1, and FEF(25-75) 79.5. Serial FEV(1) measurements in the two workers with work-related respiratory symptoms revealed a mean change in FEV(1) on the first working day of -12.9%. This contrasted with +6.25% on the last working day. Respective values for the two workers without work-related symptoms were -1.4 and +3.2%. CONCLUSIONS: Lung function changes and abnormalities in a profile of cell surface activation markers and antibodies were noted to relate to the presence of work-related respiratory symptoms, not seen in the control group.

Pulmonary response of mice to aqueous cotton dust extract.

OBJECTIVE: To determine the pulmonary response of mice to acute exposure of aqueous cotton dust extract (CDE). DESIGN: CDE was made from a standard cotton mill dust. Under mild anaesthesia, 0.05 ml of CDE was instilled intratracheally in balb/c mice. The same volume of sterile isotonic saline was instilled in controls. After 1, 5 and 10, days animals were given an overdose of pentobarbital by intraperitoneal injection, and the upper thorax was opened to expose the trachea. An incision was made and cannulae was inserted. Bronchoalveolar lavage (BAL) was done by instilling, phosphate buffer saline. Total and differential counts were done. The lavage supernatant was assayed for protein. SETTING: The laboratory of Division of Pulmonary and Critical Care Medicine, Duke University Medical Center, USA. ANIMALS: Balb/c mice. MAIN OUTCOME MEASURES: Post-exposure acute effects at bronchoalveolar level. RESULTS: Total and differential cell counts in BAL fluid were significantly higher in CDE exposed compared to controls (P < 0.01). The total mean values (expressed as cells x 10(4)) after exposure for days 1, 5 and 10 were 193.4 +/- 8.6, 177.8 +/- 7.7 and 113.5 +/- 6.4 respectively versus controls (41.6 +/- 3.4). Differential counts (cell no. x 10(4)) revealed 124.3 +/- 6.8, 94.2 +/- 7.9, 19.9 +/- 3.5 polymorph neutrophils (PNM) and 67.3 +/- 7.1, 81.6 +/- 9.4, 90.2 +/- 8.6 macrophages (AM) on days 1, 5 and 10 respectively compared to controls 2.8 +/- 2.3 (PMN) and 37.2 +/- 1.1 (AM). Analysis of protein (mg/ml BAL fluid) demonstrated a significant increase on exposure for days 5 and 10 (0.8 +/- 0.05 and 0.9 +/- 0.6 respectively versus controls, 0.09 + 0.01, p < 0.01). CONCLUSION: Acute exposure to CDE causes influx into the air spaces of inflammatory leukocytes accompanied by an increase in lung permeability (evidenced by the presence of protein in BAL fluid). In cotton mill workers, the above factors may contribute to the development of chronic byssinosis by as yet undefined agent(s) in cotton dust.