Common hazardous ingredients
Ammonium hydroxide, boric acid, carbon tetrachloride, chromate, formaldehyde, hydrochloric acid, methylene chloride, mercury, oxalate, silver, sodium hydroxide, sodium thiocyanate, trichloroethane.
Corrosive; acids can burn and blind; can cause skin, eye and lung irritation; toxic. Air and water pollutant.
Use according to label instructions. Cover all exposed skin. Wear chemical splash goggles and heavy rubber gloves. A canopy-type exhaust hood should be OK for photography development done occasionally in the home; a bathroom-type exhaust fan is not adequate.
When mixing chemical solutions, always add acid to water rather than water to acid as this causes a dangerous reaction.
Store in clearly marked, nonmetal, unbreakable containers. Keep out of reach of children and pets.
Best: Use up your unmixed chemicals or give to someone who will, such as a school, materials supplier or photography club.
If you have color photography chemicals and solutions, contact the manufacturer for disposal instructions.
Second best: If your home is connected to a city sewer system, small amounts of well mixed and diluted black-and-white photography solution can be flushed down the drain (toilet is best) with plenty of water. Contact your local sewer agency to know what is an acceptable small amount for your wastewater treatment plant.
Third best: If you are on a septic system or have large amounts of chemicals, take to a hazardous waste facility or collection event.
If you generate substantial amounts of photographic solution or generate it on a regular basis, equipment is commercially available for reclaiming the silver from the chemicals safely.