The fumes of polyvinyl chloride (PVC) wrap, generated by cutting with a hot wire, cause eye irritation, chest tightness, cough and sometimes wheezing in meat wrappers. The worker stands before a console in the refrigerated meat department and pulls the PVC paper over the meat package. She then cuts the paper with a wire heated to between 150-200°C and seals the edges with a hot plate. The labels are also heated and emit fumes before being applied to the package. Studies using questionnaires have shown a significant increase in respiratory symptoms in this group of workers compared with other employees not exposed to the meat wrapping fumes. There have been some reports of decreased flow rates after work exposure.
Andraseh and his colleagues have suggested that fumes from the thermally activated price labels rather then the PVC may be the main cause of the respiratory problems.
The syndrome of “meat wrappers asthma” has caused considerable alarm both among the employees and the employers concerned with meat wrapping in supermarkets.
Methods and Results
Group 1
Eight wrappers who, according to their union, were most troubled by symptoms, constituted group 1 (Table 1). All were women with a mean age of 51. One-half were smokers with a mean exposure of 16 pack years. One subject had an asthmatic history worsened by her work. Only one was still at work.
Their work-related symptoms were, on average, severe or moderately severe, with six of eight complaining of wheezing and cough. Six said that their symptoms were worse on cutting; two said that they were equally bad cutting and labeling. Six said that symptoms were worse at the end of the week and one said that symptoms were worse at the start of the week.
The protocol consisted of a questionnaire, control pulmonary function tests, and then a X hour period of cutting (and in some cases, an additional period of labeling). A meat wrapping machine of standard hot wire cutting type, polyvinyl chloride wrap, labels and a label heater were obtained through the cooperation of the meat wrappers’ union. Pulmonary function tests before the exposure included lung volumes, measures of airway resistance, diffusing capacity and blood gases (Table 2). They were tested sitting, in the late morning after a % hour rest period, not having smoked, exercised, or taken bronchodilators. None had symptoms of a developing or waning cold. Plethysmographic tests which did not require a deep inspiration were performed first. We followed the results of the exposure using FEV1 and FEF for three hours.
The results of the serial measurement of pulmonary function tests surprised us (Table 2). The control studies were sometimes abnormal but only in the smokers, the ex-smoker and the asthmatic. After the challenge there was no change in the average FEV1 of any worker. FEF sometimes worsened sometimes improved.
Group 2
The remoteness of workers’ occupational exposure, their concurrent exposure to cigarette smoke, the shortness of the challenge of the exposure to PVC fumes and the resting conditions detracted from the relevance of the challenge. So a second group of eight workers was selected by the union because of their symptoms of meat wrappers’ asthma. They were all at work and did not smoke (Table 3). Their symptoms were similar to, but less severe than those of the first group.
We altered the protocol to increase the exposure. All were studied on a Friday at the end of a working week. The worker exercised at 100 KPM on a bicycle ergometer as the fumes were being generated alongside. The exposure was prolonged to the limit of tolerance, always at least one hour. We followed pulmonary function for six hours. The workers took a Wright peak flow meter home to continue measuring peak flows for 12 hours; some went on for three days.
The results showed variable FEVa, N2 and FEF without a trend (Fig 1). However, results of all the pulmonary function tests of this group were normal both before and after the challenge.
Table 1—Characteristics and Symptoms
Table 2—Pulmonary Function in 8 Women
Table 3 – Characteristics and Symptoms
Figure 1. Group 2: forced exhaled volume in 1 second (FEV1), % change in N« per 500 ml exhalation (AN2) and forced exhaled flow between 25-75% of a forced vital capacity (FEF 25-75%) over a 6 hour period after challenge in die 8 subjects.