Table 1

TDI and MDI exposure periods for the nine polyurethane foam manufacturing plants and cohort sizes and person-years under observation for workers employed for at least one year

Plant	TDI exposure period	MDI exposure period	Cohort size	Person-years under observation
A	1959–73	1968–98	262	6560
B	1969–95	1969–95	71	1681
C	1973–90	1982–90	146	2712
D	1958–98	Not known	398	7872
E	1962–98	1972–98	404	9020
F	1972–92	1972–92	379	6632
G	1981–83	1970–98	955	17414
H	1958–74	1964–98	1038	20482
I	1977–87	1966–98	522	10650
Total			4175	83023