Beware before you rejoice in smoking e-cigarettes, as a study has found significant level of cancer-causing benzene in e-cigarette vapors, when the devices are operated at high power.

Benzene, a component of gasoline, has been linked to a number of diseases, including leukemia and bone marrow failure.It is found in urban air because of industrial emissions and unburned gasoline in exhaust and fuel tank leakages. Researchers from Portland State University in the US revealed that with one device operated at high power and when the e-cigarette fluid additive chemicals benzoic acid or benzaldehyde were present, benzene levels were thousands of times higher than in ambient air. The levels, nevertheless, were still 50 to 100 times lower than in smoke from conventional cigarettes, which deliver considerable benzene.

The finding appeared in the online journal PLOS ONE.It has been named the largest single cancer-risk ambient air toxin in the United States.The amount of benzene the PSU scientists measured from e-cigarettes depended greatly on the device.