Carbon black does not appear to cause significant harmful effects after a single short-term exposure, except general effects that would be expected with any fine dust (high concentrations can cause coughing and mild, temporary irritation).

Carbon black can have potentially serious respiratory effects following long- term inhalation. Refer to "Effects of Long-Term (Chronic) Exposure" below for information.

Carbon black is not irritating to the skin. It is not absorbed into the body through the skin. However, fine particles can become embedded in the skin and trapped in hair follicles causing discolouration (carbon black "tattoos") and follicular blackheads.

Carbon black dust is not irritating to the eyes except as a "foreign object". Some tearing, blinking and mild, temporary pain may occur as the solid material is rinsed from the eye by tears.

Carbon black is probably not toxic following ingestion. There is no human or animal information available. Ingestion is not a typical route of occupational exposure.

INHALATION: Carbon black dust is extremely fine and light and can be breathed deeply into the lungs, where it can accumulate. Normally the dust is cleared gradually from the lungs and has no harmful effects. However, high concentrations of dust can overwhelm the clearance capacity of the lungs, obstruct the lungs, and interfere with lung function. Symptoms may include coughing, increased phlegm production, and shortness of breath. A number of studies have shown x-ray changes, reduced lung function, emphysema and/or chronic bronchitis in some carbon black workers. In other studies, no respiratory effects were seen. A few studies have shown evidence of fibrosis (scarring of the lungs) in the area surrounding carbon black deposits in the lungs.

Non-specific irritant effects including cough and changes in lung function, have been observed in workers occupationally exposed to carbon black. In one case, these effects were seen in workers exposed to airborne concentrations of up to 0.45 mg/m³ respirable dust and up to 1.60 mg/m³ total dust. Interpretation of the studies is complicated by the lack of exposure information (airborne concentration of carbon black, duration of exposure and/or particle size), small study population size, lack of information regarding smoking history and lack of information about other potential occupational exposures. At this time, it is not possible to establish a dose-response relationship between exposure levels and specific effects. However, limited animal and human evidence suggests that significant and potentially irreversible lung effects may occur with exposures to high airborne concentrations (10-100 mg/m³).

SKIN CONTACT: Fine particles can become embedded in the skin and trapped in hair follicles causing discolouration (carbon black "tattoos") and follicular blackheads.

The International Agency for Research on Cancer (IARC) has based its conclusions on four studies conducted to evaluate lung cancer risk among carbon black-exposed workers. Of these, two were positive, one was positive but not statistically significant and the other was negative. Overall results are conflicting and IARC considers the evidence rather weak. Studies evaluating skin cancer risk have shown no excess risk. Isolated findings of cancers of the urinary bladder, kidney and oesophagus are considered insufficient to support an evaluation of human carcinogenicity.

The International Agency for Research on Cancer (IARC) has concluded that there is inadequate evidence for the carcinogenicity of carbon black to humans and that there is sufficient evidence that carbon black is carcinogenic to experimental animals. Overall IARC evaluation of carcinogenic risk: Group 2B (possibly carcinogenic to humans).

There is no human or animal information available.

There is no human or animal information available.

There is no information available.

Generally, inhaled or ingested carbon black is not absorbed into the body. Some inhaled carbon black is retained in the lungs, while ingested material is excreted.