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¦.
Inactivated Typhoid Vaccine (Shot). 1  Should not be given to children younger than 2 years of age. 2  One dose provides protection. 3  It should be given at least 2 weeks before travel to allow the vaccine time to work.ive Typhoid Vaccine (Oral). 1  Should not be given to children younger than 6 years of age. 2  Four doses, given 2 days apart, are needed for protection. 3  A booster dose is needed every 5 years for people who remain at risk.