Here you go.
"Your gas hot water heater seems safe enough, sitting there day after day providing a continual supply of water when you need it.
But if you store flammable substances in its vicinity, that same water heater could trigger a fire or even explosion.
According to estimates by federal safety officials and heater manufacturers, hundreds or even thousands of fires and explosions occur each year because people use or store gasoline, paint solvents or other flammable substances near gas-fired hot water heaters in basements, garages and other locations.
``Those vapors accumulate and could be ignited by the pilot light,'' said Robert A. Hauserman, director of customer service for Connecticut Natural Gas Corp.
But the issue has caused such concern that gas appliance manufacturers have spent more than $6 million since 1993 studying the problem and running a national education campaign to warn the public. Those efforts were prompted by the federal Consumer Product Safety Commission, which is hoping the industry can find a way to build a heater that is both economical to buy and resists setting off volatile gases.
Federal officials are concerned about incidents such as the one in June 1992, in which a heater was blamed for igniting gasoline vapors from a motorcycle being stored in a two-family home in Essex, Mass. The structure was severely damaged by the resulting blaze. In August 1983, a 2-year-old boy suffered first- and second-degree burns when a hot water heater ignited gasoline fumes in a home in Manomet, Mass. Investigators concluded that the child knocked over a container of gasoline when he went into the basement to look for his father.
Although furnaces and kitchen ranges also can pose such a danger, hot water heaters most often are to blame, causing about 76 percent of all incidents involving the ignition of flammable vapors. In contrast, ranges cause about 20 percent, and heating equipment 4 percent."
Source: articles.courant.com/.../
New gas hot water tanks are sealed, but I still wouldn't store gas near one. As for garage heaters most are up by the ceiling, and as I stated previously the fumes stay low, plus garages are not as air tight as a house.