Is that a no-smoking sign ?   Yes , it is . As you know , some of the materials we use are highly-flammable so we have a very strict non-smoking policy in the factory .   What does that sign mean ?   It means there must be no naked flames or sparks anywhere near flammable materials . If the materials ignite , it could cause a serious fire and the fumes they give off can be very dangerous if you inhale them . 