Keep in mind these requirements are distinct; you may go well over the 4,500 hours but still not meet the duration requirement if those hours were not spread over a three-year period. For example, assume you worked on two projects at the same time, over a two-year period.
Nicotine is the main ingredient of concern in smokeless tobacco. It is estimated that a normal, 30-minute dip of smokeless tobacco delivers the same amount of nicotine as 3-4 cigarettes. Nicotine affects the brain and central nervous system and changes neurotransmitters levels regulating mood, learning, alertness, and ability to concentrate.
No. There is no scientific evidence that using smokeless tobacco can help a person quit smoking (7). Because all tobacco products are harmful and cause cancer, the use of all tobacco products is strongly discouraged. There is no safe level of tobacco use.