Are nicotine vapor products as safe as using smokeless tobacco?
From Safer nicotine wiki
Maybe. Today, we are confident that vaping is safer than smoking. But compared to smokeless tobacco, vapor products are relatively new. To date, the longest study following a group of vapers collected data for 3.5 years. Long term studies will need to consider data collected over 10, 15, or 20 years. For the time being, it is reasonable to assume that vapor and smokeless tobacco pose similar risks. Read more here.