There are many types of acids and alkalies used in photography. In general, acids and alkalies are similar in their injurious properties in that either may cause the following:

Corrosion (chemical burn) by direct contact with the skin or eyes or indirectly through the clothing.

Intoxication or suffocation by inhalation of their fumes. The fumes of some compounds are toxic or poisonous, while others displace air, thereby producing a suffocating atmosphere.

Poisoning when taken internally.

Fire and explosion because of their instability under adverse storage conditions. Also, some acids are strong oxidizing agents that can generate ignition temperatures upon contact with organic materials and other chemicals.

PRECAUTIONS

There are several safety items that must be worn when mixing chemicals. They are as follows:

1. Face shield or goggles-Protects the eyes from caustic chemicals.

2. Plastic or rubber apron-Reduces the chance of chemical contamination of clothing.

3. Rubber gloves-Protects the hands and lower arms. Gloves should extend up to the elbows.

4. Respirators-Used to prevent the inhalation of fumes or chemical dust. The correct cartridge must be used for the type of chemical being mixed as described in Navy Occupational Safety and Health (NAVOSH) Program Manual, OPNAVINST 5100.23 series (app. 15).

Respirators must be cleaned and sanitized with alcohol and placed in an airtight bag after each use.

5. Long sleeve shirt-Used to protect the arms.

The majority of photographic chemicals cause the skin to dry out due to the removal of natural skin oils. Some types of chemistry have an accumulative nature. This is when some of the chemicals are being absorbed into the skin layers during each exposure to the chemistry. The chemistry then replaces some of the natural oils that lubricate the skin. Over an extended period of time, which varies for different people, accumulation could result in a total breakdown of the ability of the skin to produce natural fats and lubricating oils. Extreme conditions can result in contact dermatitis. Metol (developing agent) poisoning can be a result of accumulation poisoning.

Certain precautions must be observed in areas where acids and strong alkalies are handled. These precautions are as follows:

Warning signs and labels-Signs should be posted in the chemical mixing area, warning personnel of the principal hazards of the chemical being used. All containers must be properly identified with hazardous material labels.

Showers and eyewash stations-Showers and eyewash stations must be provided near all chemical mixing areas.

Ventilation-In a chemical mixing area, exhaust ventilation must be provided The exhaust vent must draw vapors away from the person mixing the chemicals and provide a complete air change once every 3 minutes (20 changes per hour).

Mixing and diluting-Strong acids and strong oxidizing agents may react violently or produce explosive products. Toxic gases may be created when acid is mixed with such chemicals as sulfides, cyanides, nitrates, and nitrites. Diluting acids with water can generate considerable heat; acid should always be added to water, not water to acid. The addition should be done slowly with constant stirring.

Never smell a chemical directly from the bottle; instead, hold the bottle at a distance from your nose and sniff its contents cautiously rather than inhale directly.

Never taste a chemical. produce burns or skin irritation.