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Metal Working Patina Hazards

ID Patina Chemical Other Names Ingestion Haz Inhalation Haz Skin Contact Haz Other Hazards
1 Acetic Acid
Highly toxic Highly toxic Highly toxic TLV 10 ppm; concentrate very corrosive; ingestion may be fatal; may cause chronic bronchitis; vinegar is 2-3% acetic acid
2 Ammonia
Moderately toxic to highly toxic Highly toxic Highly toxic TLV 25 ppm; household ammonia is 5-10% ammonia; skin contact can cause burns; high concentrations can cause chemical pneumonia; mixing w/alkalis releases ammonia gas; mixing w/chlorine bleach forms poison gas
3 Ammonium Chloride
Slightly toxic Slightly toxic Not significantly toxic TLV 10 mg/m3; if heated, it decomposes to hydrogen chloride, ammonia, which are strong respiratory irritants
4 Ammonium Nitrate
Moderately toxic Slightly toxic Not significantly toxic Very powerful oxidizing agent, which can react explosively w/solvents, organic materials, acids
5 Ammonium Sulfate
Slightly toxic Slightly toxic Slightly toxic If heated, it decomposes to form irritating ammonia and sulfur oxides
6 Ammonium Sulfide
Extremely toxic Highly toxic Moderately toxic Releases extremely toxic hydrogen sulfide gas; if heated/treated w/acid, it decomposes to form ammonia, hydrogen sulfide gas; hydrogen sulfide can also form in stomach due to reaction w/stomach acid, if ingested
7 Arsenic Oxide
Extremely toxic Extremely toxic Highly toxic PEL 0.01 mg/m3, NIOSH C 0.002 mg/m3; known carcinogen; acute ingestion may be fatal; reaction w/acid forms poisonous arsine gas; causes skin irritation, cancer, kidney & liver damage; nervous system damage; DO NOT USE
8 Barium Sulfide
Extremely toxic Highly toxic Moderately toxic TLV 0.5 mg/m3; may cause skin/eye/nose/throat irritation, intestinal spasms, heart irregularities, muscle pain; releases extremely hydrogen sulfide gas; reacts w/acid to form hydrogen sulfide (can react w/stomach acid, if ingested)
9 Chromium VI Compounds Chromium trioxide, potassium dichromate Highly toxic to extremely toxic Highly toxic to extremely toxic Highly toxic TLV 0.05 mg/m3, NIOSH 0.001 mg/m3; known carcinogen; strong oxidizing agents; corrosive; may cause irritation, ulcer, allergies, cancer, gastroenteritis, circulatory collapse, kidney damage; DO NOT USE
10 Copper Compounds Copper sulfate, copper carbonate, copper chloride, copper nitrate Highly toxic Moderately toxic Slightly toxic TLV 1 mg/m3, PEL 0.1 mg/m3; may cause irritation, ulcer, congestion, metal fume fever, gastrointestinal irritation, vomiting
11 Ferric Chloride Iron perchloride Moderately toxic Slightly toxic Moderately toxic Powder; forms hydrochloric acid in solution; ingestion of large amounts. by children could cause iron poisoning; heating releases highly toxic hydrogen chloride gas, which causes lung irritation, pulmonary edema
12 Hydrochloric Acid Muriatic acid Highly toxic Highly toxic Highly toxic Concentrates highly corrosive; causes severe stomach damage, lung irritation; possible chronic bronchitis; diluted acid less haz., but still causes skin/eye irritation; vapors highly toxic if inhaled
13 Hydrogen Peroxide (Concentrated)
Highly toxic Slightly toxic Moderately toxic TLV 1 ppm; corrosive to skin, eyes, gastrointestinal system, strong oxidizing agent; dilute solutions not considered haz.; may react w/ flammable liquids, combustible materials, some metal salts
14 Iodine
Extremely toxic Highly toxic Moderately toxic TLV-C 0.1 ppm; corrosive; skin contact may cause hypersensitivity and burns; oxidizing agent; inhalation causes severe respiratory irritation similar to chlorine gas, but at room temperature, not much of a problem because of low volatility; may be fatal
15 Lead Acetate
Highly toxic Highly toxic Not significantly toxic PEL 0.05 mg/m3; probable carcinogen, mutagen, developmental toxicant; may cause lead poisoning, causing lead colic, anemia, weakening of joints, headaches, irritability, malaise, pain in joints, kidney damage, birth defects; DO NOT USE
16 Liver of Sulfur (see Potassium Sulfide)




17 Nitric Acid
Highly toxic Highly toxic Highly toxic TLV 2 ppm; concentrate highly corrosive; strong oxidizer; reacts w/copper & alloys to form highly toxic nitrogen dioxide gas; can cause severe stomach damage, skin, eye irritation, emphysema
18 Oxalic Acid
Highly toxic Moderately toxic Highly toxic TLV 1 mg/m3; powder and solutions corrosive to skin, eyes, respiratory system, gastrointestinal system; causes kidney damage, gangrene of extremities, gastroenteritis
19 Platinum Chloride
Unknown Highly toxic Moderately toxic TLV 0.002 mg/m3; causes skin allergies, nasal allergies, asthma, lung scarring, emphysema; people w/red or light hair and fine-textured skin most susceptible
20 Potassium Chlorate
Highly toxic Moderately toxic Moderately toxic Strong oxidizing agent used in pyrotechnics; skin, eye, respiratory irritant; ingestion causes gastritis, methemoglobinemia, kidney damage; DO NOT USE
21 Potassium Ferricyanide
Moderately toxic Slightly toxic Slightly toxic When heated strongly, treated w/acid, or exposed to uv radiation, decomposes to form poisonous hydrogen cyanide gas
22 Potassium Sulfide Potassium polysulfide, liver of sulfur Extremely toxic Highly toxic Moderately toxic Reaction involves release of extremely toxic hydrogen sulfide gas; if heated/treated w/acid, it decomposes to form hydrogen sulfide gas; can also happen in stomach due to reaction w/stomach acid, if ingested
23 Sodium Hydroxide Lye Highly toxic Highly toxic Highly toxic TLV-C 2 mg/m3; highly corrosive; ingestion can cause severe pain and damage to mouth and esophagus, and can be fatal; inhalation can cause chemical pneumonia; dilute alkaline solutions more corrosive than dilute acid solutions
24 Sodium Thiosulfate
Moderately toxic Highly toxic Not significantly toxic Ingestion can cause purging; reacting w/acid or heating causes decomposition to sulfur dioxide; aqueous solutions also decompose to form sulfur dioxide; chronic inhalation causes bronchitis; asthmatics especially sensitive to sulfur dioxide
25 Zinc Chloride
Highly toxic Highly toxic Moderately toxic TLV 1 mg/m3; corrosive to skin, eyes, stomach; inhalation of fumes from heating highly irritating to respiratory system and may cause bronchitis/pulmonary edema