Table 4

Bladder cancer: SIR by workplace type and RIR by period of hire, duration of employment, years since hire, highest hydrocarbon ranking job held, and hydrocarbon ranking of job held longest, adjusted for age, calendar year; RIRs also adjusted for smoking

Workplace type	Person-years	Obs/Exp	SIR	95% CI
Refinery	69795	21/14.2	1.48	0.92 to 2.26
Terminal	73373	18/15.1	1.19	0.71 to 1.88
Airport	6877	4/1.4	2.85	0.78 to 7.29
Onshore production	19629	2/2.2	0.9	0.11 to 3.27
Offshore production	6924	1/0.6	1.61	0.04 to 8.96

Period of hire	Person-years	Cases	RIR*	95% CI
Post-1975	79838	9	1
1965–74	60283	13	0.82	0.32 to 2.08
1955–64	24837	16	0.98	0.35 to 2.75
Pre-1955	11640	8	0.68	0.21 to 2.24

Years of employment	Person-years	Cases	RIR†	95% CI
5–9	45836	4	1
10–15	43718	10	1.45	0.44 to 4.80
15–19	32976	6	0.74	0.20 to 2.81
20–24	21475	2	0.25	0.04 to 1.45
25+	32593	24	0.99	0.29 to 3.40

Years since hire	Person-years	Cases	RIR‡	95% CI
5–9	37624	4	1
10–14	41147	5	0.68	0.18 to 2.61
15–19	34372	6	0.57	0.15 to 2.21
20–24	23741	6	0.47	0.11 to 1.94
25+	39714	25	0.44	0.12 to 1.65

Highest hydrocarbon ranking job	Person-years	Cases	RIR§	95% CI
1	33991	6	1
2	14986	1	0.79	0.09 to 6.68
3	1912		0
4	80583	23	2.06	0.83 to 5.08
5	6430	2	2.65	0.53 to 13.2
6	28420	9	2.21	0.78 to 6.26
7	10252	5	3.74	1.14 to 12.3

Hydrocarbon ranking longest job	Person-years	Cases	RIR¶	95% CI
Tests for trend: *p = 0.63, †p = 0.60, ‡p = 0.24, §p = 0.02, ¶p = 0.09.
1	45922	8	1
2	15856	1	0.66	0.08 to 5.34
3	2959	0	0
4	74258	25	2.02	0.91 to 4.48
5	4723	1	1.32	0.17 to 10.6
6	25187	8	1.84	0.69 to 4.92
7	5011	2	2.11	0.45 to 9.95