A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 1-9

Copper Oxide - Red

Key Data

Formula: Cu2O
CAS: 1317-39-1
Other names: Copper (I) oxide, cuprous oxide, cuprite
Appearance: Brownish red powder
Solubility: Insoluble in water, but soluble in acids
Melting Point: 1232°C



A pigment in glazes.

Exposure Routes

Skin and Eye Exposure

Copper oxide can act as an eye irritant.

Some people have an allergic reaction to copper metal, causing itching. There's no data on if this occurs with copper oxide.

Skin Absorption

Not absorbed if dry or in water.


Copper dust is a respiratory irritant, causing coughing, sneezing and a runny nose at low levels, and long term, very high levels leading to pulmonary fibrosis and increased vascularity of the nasal mucosa. However there is no data on whether this applies to copper oxide.

There is very little data on copper absorption throught the lungs, but it looks as though absorption rates are very low.


Up to 60% of ingested copper can be absorbed into the body, but the greater the concentration of copper in the gut, the lower the absorption rate. This tends to make the rate of absorption self-limiting.

As red copper oxide is soluble in acids, the rate of absorption is likely to be higher than insoluble forms.


Excess copper can attack the liver and kidney, and may also have an adverse effect on the immune system.



No effect.



The minimum risk level (MRL) for ingestion of copper is 0.01mg/kg bw/day, so for red copper oxide is 0.0225mg/kg bw/day, i.e. 1.35mg/day for a 60kg person.

Ingestion of a single dose of about 0.04 mg/kg bw (0.017-0.018 mg Cu/kg bw) (2.3mg for a 60kg person) can result in nausea, vomiting and abdominal pain. This is transient, and doesn't cause any long term problems.

Ingestion of large quantities can be toxic. but the level for this is far greater than the potter will encounter.

Repeat Dose

There are three rare diseases that result in excessive concentrations of copper in the liver, and resultant severe liver damage: Wilson’s disease, Indian childhood cirrhosis, and idiopathic copper toxicosis.



Prolonged inhalation of copper or copper sulfate irritates the respiratory tract, though there is no evidence to show whether or not this is also the case for copper oxide.



No known effects. Animals tests on some other copper compounds have shown some genotoxicity, but these have not been found in humans.


Not a carcinogen.

Reproductive Toxicity

No known effects.

Health and Safety Practice


Regulatory Requirements

Dust Limits

OrganisationLimit mg/m3 as CuNotes
ACGIH0.2For fumes. 8 hour TWA
ACGIH1For dusts and mists. 8 hour TWA
NIOSH REL0.1For fumes. 10 hour TWA
NIOSH REL1For dusts and mists. 10 hour TWA
OSHA PEL0.1For fumes. 8 hour TWA
OSHA PEL1For dusts and mists. 8 hour TWA
PAC-10.68Notable discomfort level
PAC-216Long lasting or irreversible serious adverse health effects
PAC-393Life threatening effects or death
UK HSE1For dusts and mists. 8 hour TWA
UK HSE2For dusts and mists. 15 min TWA
UK HSE0.2Copper fume (as Cu). 8 hour TWA