Use effective fume removal device to protect against acid fumes or alkali dusts or vapors. Always add concentrated sulfuric acid or sodium hydroxide pellets to water, not vice versa. Concentrated sodium hydroxide can quickly and easily cause blindness. If splashed on skin or in eyes, flush with copious amounts of water and seek medical attention. Mercury in contact with ammonia, halogens and alkali can produce extremely toxic and cumulative vapors.
Regard spills as extremely hazardous and clean up promptly.
Powdered sulfur sprinkled over spilled mercury can assist in cleaning up spills. A high degree of personal cleanliness is necessary for persons who use mercury. Use skin and respiratory protection when dry mercuric salts are to be used. The sulfur oxide fumes produced during digestion are hazardous to inhale. Digests must be cool before dilution water is added to avoid a violent reaction during which the acid can shoot out of the flask.