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1.  Byssinosis in the Waste Cotton Industry 
This paper is of some historical interest. It describes an investigation to determine whether byssinosis occurred among workers in the waste cotton industry. It was undertaken in 1950 at the instigation of the Minister of National Insurance.
The materials used in the industry were (1) cotton that had been previously spun, and (2) waste material discarded during the preparations for spinning higher grades of yarn. A proportion of raw cotton was sometimes blended with the waste.
Twenty-two mills, representative of the industry, were surveyed. All the men in these mills, who were over 35 years of age and with at least 10 years' exposure to cotton dust, were seen. The investigations included a work history, a clinical examination, an assessment of effort dyspnoea, and a chest radiograph.
There were 140 men who had never been exposed to any dust hazard other than waste cotton. In this group were found seven (5%) men with disabling byssinosis and 35 (25%) men with lesser degrees of the same disease. There were also 15 (11%) men with bronchitis or emphysema without byssinosis.
Thus it was established that byssinosis did occur in the waste cotton industry. Insurance cover, under the National Insurance (Industrial Injuries) Act, 1946, was subsequently extended to workers in the waste cotton industry.
The survey provided no evidence that either the type of waste cotton processed or an admixture of raw cotton played a significant part in the aetiology or incidence of the disease.
PMCID: PMC1008348  PMID: 5904098
2.  A Follow-up Study of Lead Workers 
Following the suggestion that lead derivatives might cause cancer in man, the causes of death among workers known to have been exposed to lead were studied. A group of companies made available the records of their pension fund, and an accumulator factory provided details of men who had died whilst in their employ. Details of each man's exposure to lead were supplied.
There were 425 pensioners, of whom 184 had died; 153 deaths occurred among an unknown number of employed men who had not yet reached pensionable age. Expected deaths were calculated from the appropriate rates for all males in England and Wales.
It was concluded that there was no evidence to suggest that malignant disease was related to lead absorption. There was, however, evidence that heavy exposure to lead was associated with an increased incidence of deaths from cerebrovascular catastrophies.
PMCID: PMC1038384  PMID: 14072623
3.  The Reliability of Repeated Auditory Threshold Determination 
This paper considers the precision which may be expected in short-term serial measurements of audiometric thresholds.
Twelve otologically normal young men were tested on four separate occasions at 1, 2, 3, 4, 6, 8, 0·5, and 1 kc/s. The tests were carried out in a mobile test room installed in a specially constructed vehicle chassis.
The acoustic output of the audiometer and ear-phones was measured at intervals throughout the investigation. Output stability with variations of mains supply voltage and drift during the warming-up period of the instrument were also measured.
It was concluded that the instrument variation had been extremely slight throughout the investigation.
The estimates of variance of repeated threshold determinations on a single ear were found to be 8·5 (dB)2 at 0·5 kc/s, 6 (dB)2 at 3 kc/s, and 23 (dB)2 at 8 kc/s. Differences between consecutive determinations extended to 25 dB.
These results were obtained under conditions which practically precluded all sources of variation other than that due to the inherent uncertainty of audiometric measurements. It appears to follow, therefore, that if an apparent drop in auditory threshold in one ear is to be considered as significant evidence (P = 1%) of a real change, the difference would have to be at least 17·5 dB at the higher frequencies. This level could possibly be reduced to 10 dB if the change occurred simultaneously at both 4 and 6 kc/s.
PMCID: PMC1039205  PMID: 14046161

Results 1-6 (6)