Temporal and seasonal occurrence of chemical incidents in the West Midlands region, UK: 1997–2001
| Type of chemical incident reported, n (%) | |||||||
|---|---|---|---|---|---|---|---|
| Deposit | Spill/leak | Fire/explosion | Releases | Other | Unknown | Total | |
| All events | 85 | 355 | 340 | 87 | 107 | 55 | 1029 |
| Study year | |||||||
| 1997 | 2 (2.4) | 23 (6.5) | 17 (5.0) | 5 (5.7) | 9 (8.4) | 21 (38.2) | 77 (7.5) |
| 1998 | 17 (20.0) | 60 (16.9) | 50 (14.7) | 19 (21.8) | 7 (6.5) | 9 (16.4) | 162 (15.7) |
| 1999 | 13 (15.3) | 81 (22.8) | 64 (18.8) | 24 (27.6) | 30 (28.0) | 10 (18.2) | 222 (21.6) |
| 2000 | 30 (35.3) | 91 (25.6) | 117 (34.4) | 16 (18.4) | 23 (21.5) | 9 (16.4) | 286 (27.8) |
| 2001 | 23 (27.1) | 100 (28.2) | 92 (27.1) | 23 (26.4) | 38 (35.5) | 6 (10.9) | 282 (27.4) |
| Season | |||||||
| Spring | 20 (23.5) | 83 (23.4) | 89 (26.2) | 20 (23.0) | 24 (22.4) | 16 (29.1) | 252 (24.5) |
| Summer | 18 (21.2) | 104 (29.3) | 111 (32.6) | 32 (36.8) | 29 (27.1) | 8 (14.5) | 302 (29.3) |
| Autumn | 28 (32.9) | 98 (27.6) | 70 (20.6) | 18 (20.7) | 35 (32.7) | 14 (25.5) | 263 (25.6) |
| Winter | 19 (22.4) | 70 (19.7) | 70 (20.6) | 17 (19.5) | 19 (17.8) | 17 (30.9) | 212 (20.6) |
| Day of the week | |||||||
| Monday | 14 (16.5) | 48 (13.5) | 54 (15.9) | 14 (16.1) | 19 (17.8) | 10 (18.2) | 159 (15.5) |
| Tuesday | 16 (18.8) | 59 (16.6) | 44 (12.9) | 12 (13.8) | 23 (21.5) | 8 (14.5) | 162 (15.7) |
| Wednesday | 13 (15.3) | 63 (17.7) | 39 (11.5) | 21 (24.1) | 24 (22.4) | 9 (16.4) | 169 (16.4) |
| Thursday | 13 (15.3) | 68 (19.2) | 59 (17.4) | 12 (13.8) | 13 (12.1) | 11 (20.0) | 176 (17.1) |
| Friday | 14 (16.5) | 62 (17.5) | 52 (15.3) | 14 (16.1) | 14 (13.1) | 12 (21.8) | 168 (16.3) |
| Saturday | 7 (8.2) | 27 (7.6) | 40 (11.8) | 8 (9.2) | 7 (6.5) | 3 (5.5) | 92 (8.9) |
| Sunday | 8 (9.4) | 28 (7.9) | 52 (15.3) | 6 (6.9) | 7 (6.5) | 2 (3.6) | 103 (10.0) |
| Time of day (6 hourly) | |||||||
| 00 00–05 59 | 11 (12.9) | 55 (15.5) | 62 (18.2) | 35 (40.2) | 35 (32.7) | 20 (36.4) | 218 (21.2) |
| 06 00–11 59 | 17 (20.0) | 104 (29.3) | 68 (20.0) | 23 (26.4) | 29 (27.1) | 12 (21.8) | 253 (24.6) |
| 12 00–17 59 | 33 (38.8) | 118 (33.2) | 102 (30.0) | 21 (24.1) | 29 (27.1) | 17 (30.9) | 320 (31.1) |
| 18 00–23 59 | 24 (28.2) | 78 (22.0) | 108 (31.8) | 8 (9.2) | 14 (13.1) | 6 (10.9) | 238 (23.1) |