Downright dangerous - Projects listed for knowledge basis only. These are best left well enough alone. More than one of the above symbols appearing on a page indicates a range. Involves the use of chemicals or toxic materials. Refer to any warnings or safety precautions involving the particular chemical used.
Electricity can cause severe injuries or even death, so take all possible precautions.
Fire or heat. Handle all sources of heat safely. Avoid use of flame near combustible materials. Live animals or plants involved. Take every precaution to avoid injury to yourself or to the animals.