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¦.
The typhoid oral vaccine is given in a series of 4 capsules that are taken 1 per day on alternating days (days 1, 3, 5, and 7). On this schedule, you will take 1 capsule every 48 hours for 7 days. Take each capsule according to the recommended schedule or this vaccine may not be effective.