Factors contributing to nail gun injuries* among union residential carpenters by trigger mechanism of tool, 1999–2002; values are number (%)
| Type of trigger mechanism† | ||
|---|---|---|
| Contributing factor | Contact trip trigger (n=53) | Sequential trigger (n=18) |
| *Categories are not mutually exclusive. | ||
| †Triggering mechanism unknown for nine injuries. | ||
| Use of non-dominant hand to handle tool | 6 (11) | 2 (11) |
| Placement of hand not holding tool/body (bracing materials, shooting towards self) | 18 (33) | 9 (50) |
| Awkward posture (work in rafters, leaning over, overhead, shooting back towards self) | 8 (15) | 3 (17) |
| Nail ricocheted (knot, laminated beams, metal truss components) | 12 (23) | 6 (33) |
| Rapid double fire, uncontrolled, misfire | 17 (32) | 1 (6) |
| Penetration of wood surface | 11 (21) | 4 (22) |
| Projectile nail | 9 (17) | 0 |
| By-passed safety mechanism | 19 (36) | 0 |
| Lack of eye protection | 2 (4) | 1 (6) |