Table 4 Setting weight by operating period
Operating Period (year) | Weight by period | Evidence |
|---|---|---|
1966 (Initial operation)-1974 | 3.5 | The average concentration of CS2 in the spinning division in the 1960s (20 ppm) was about 3.5 times the average concentration of the total spinning division measured in 1991 (5.6 ppm). |
1975–1989 | 2.75 | The average concentration in the spinning division measured in the 70s and 80s (10–15 ppm) was about 2.25 times the average concentration in the total spinning division measured in 1991 (5.6 ppm). Since 1975, the production of rayon has increased. According to the operator interview, the exhaust system has changed, and the screen breaks down due to the age of the equipment. Thus, an additional weight of 0.5 was included. |
1990–1993 (Upon closure) | 0.5 | The compliance towards wearing personal protective gear was relatively good. The highest CS2 exposure concentration measured in protective equipment (3.2 ppm) was about 0.5 times that measured in 1991 (5.6 ppm). |