Read the labels for directions on storage and never mix volatile chemicals. The best examples of this are chlorine products and ammonia products. A gas is produced that can be hazardous to your health. Drain cleaners should also be handled carefully. When pouring into water, never use cleaners that contain acid.
Acid spits and gurgles when poured into water and can then get into the eyes and on skin.
Only use acid decloggers when the drain is free and clear of water. Never look into the drain as you pour because the chemical can erupt and splash in your face. Proper drain cleaners are available to pour into standing water. Never mix these types with acid types. Other chemicals you should be concerned about are those in your workshop.