We just got the results back from the test lab for nickel testing under normal vaporizing conditions. To get double the amount of nickel fumes that are normally breathed in during a day*, you would have to use the Lotus from 700 to 7000 times per day at normal vaporizing temperatures. We don't recommend that you use it that often. The lab results will be posted on our website next week. *According to the CDC the amount of nickel fumes a person breathes in varies from .1 to 1 micrograms per day.