OSHA defines an excavation as any man-made cut, cavity, trench, or depression in the earths surface formed by earth removal. A trench is defined as a narrow underground excavation that is deeper than it is wide, and is no wider than 15 feet (4.5 meters). Dangers of Trenching and Excavation. Cave-ins pose the greatest risk and are much more likely than other excavationrelated accidents to result in worker fatalities.
How long does a typhoid shot last?   According to the CDC website, a booster dose is needed every 2 years for people who remain at risk.. The oral (live) vaccine lasts 5 years before another dose is neededâ¦.
Tetanus - 10 years ; Typhoid - 3 years ; Yellow Fever - 10 years ; what are the likely side effects: These days, vaccines cause fewer problems than in the past. On the day of vaccination, most people can work, drive a car, play sport or go to the gym, but it is best to 'take it easy'. Modern vaccines do not leave a scar. Any vaccine can cause rare and less common reactions.