True or False: It is safe to use flammable materials in poorly ventilated spaces.

Using flammable materials in poorly ventilated spaces is not safe due to the increased risk of fire and explosion. In such environments, the concentration of flammable vapors can build up to dangerous levels, and without adequate ventilation, these vapors are unable to dissipate. This can create a hazardous atmosphere where even a small spark or ignition source can lead to serious incidents.

The correct answer, therefore, is that it is false to claim that it's safe to use flammable materials in these conditions. Proper ventilation is crucial to ensure that any potentially harmful vapors are adequately dispersed, minimizing the risk of ignition and allowing for a safer working environment.