SAN FRANCISCO — Fabled as a mecca for the health-conscious and fitness-obsessed, California is also one of only a few states that hasn’t hiked cigarette taxes in the last decade — and the tobacco industry wants to keep it that way.

Cycling star Lance Armstrong has championed a $1-per-pack tax on cigarettes and other tobacco products to fund cancer research in a proposal that will go before voters Tuesday.

But tobacco companies and their allies have amassed nearly $50 million to fund a media blitz to snuff out Proposition 29.

With less than a week to go before the California primary, the measure’s passage is uncertain.