There are no reports of effects following short-term inhalation of aluminum. In general, high concentrations of dust may cause coughing and mild, temporary irritation. Certain types of aluminum powder may cause effects following long-term exposure (see Effects of Long-term Exposure below).

Aluminum dust is not irritating to the skin, based on animal information. There is no human information available.

It has generally been considered that aluminum is very poorly absorbed through the skin. Animal toxicity values for aluminum salts indicate that toxic effects would not be expected following short-term skin contact.

No irritation or inflammation has been observed in cases where aluminum has become embedded in the eyes. Temporary irritation has been observed in animal studies. The dust is probably not irritating to the eye, 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.

Short-term oral toxicity is low. Aluminum is a normal component of the human diet and the normal daily intake is significant. In adults, daily aluminum intake has been estimated at about 9 to 14 mg in one reference and 1 to 100 mg (mean 5 mg) in another, and can be much higher (1000 mg or more) in individuals taking antacids containing aluminum hydroxide. No animal toxicity values are available since death occurs from intestinal blockage rather than systemic toxicity. Ingestion is not a typical route of occupational exposure.

LUNG EFFECTS: No conclusions can be drawn regarding the possible long-term effects of aluminum on the lungs. Historically, several cases of scarring of lung tissue (pulmonary fibrosis) have been observed following prolonged or repeated occupational exposure to certain types of aluminum dust, either a molten pellet variety or stamped aluminum powder (also called pyro powder). Pulmonary fibrosis is a potentially serious lung disease which, in severe cases, may lead to death. Airborne dust concentrations required to produce the effects were not well documented and there was exposure to other chemicals at the same time. Some reviewers have concluded that the lung effects may have been related to a mineral oil-based lubricant historically used to treat pyro powders in Germany and the United Kingdom. Pulmonary fibrosis has not been observed following more recent occupational exposures to coarser granulated aluminum dust, manufactured from melted aluminum, aluminum pigment flake or pyro powders treated with stearin.

Reduced lung function, consistent with chronic airflow limitation, has been observed in aluminum production workers although the cause has not been determined and exposures to many different airborne substances occur in this industry.

One case of injury to the lower lung (pulmonary alveolar proteinosis) has been reported in a worker employed as an aluminum grinder. This disease may or may not be reversible. No details of the level of exposure were reported. Similar effects have been observed in experimental animals. However, no conclusions can be drawn based on this limited information.

NEUROLOGICAL EFFECTS: A link between exposure to aluminum or aluminum compounds and Alzheimer's disease or other neurological diseases has been suggested. This link was suggested because of severe neurological effects which have been observed in patients receiving dialysis treatment (with dialysis fluids containing aluminum); effects seen in animals exposed to aluminum using non-occupational routes of exposure; case reports of neurological effects in individual workers; and findings of elevated aluminum levels in the brains of patients with neurological diseases. At present, whether or not this association is a true effect is controversial and findings are inconsistent. Recent reviewers have concluded that the evidence is inadequate to establish a link between occupational exposure to aluminum and specific effects on the nervous system or Alzheimer's disease, in normal, healthy workers. One reviewer has concluded that there is a likely connection between long-term occupational exposure to aluminum and a specific effect, impaired co-ordination, but not other toxic effects on the nervous system or Alzheimer's disease.

One case of brain disease (encephalopathy) involving convulsions, as well as pulmonary fibrosis, was observed in a worker occupationally exposed to aluminum flake powder. These effects were not observed in another 53 workers similarly exposed. In another study, follow-up of 2 employees who had been diagnosed with fibrosis, following exposure to pyro powder in the 1930's and 1940's, revealed that one had developed a brain disorder (dementia with motor disturbances). No firm conclusions can be drawn based on these limited findings.

SKIN CONTACT: One recent report indicates that aluminum can be absorbed through the skin of mice following long-term application of a water soluble salt (aluminum chloride hexahydrate). This study indicates that long-term skin contact may contribute to overall exposure and accumulation of aluminum in the body. The relevance of this finding to aluminum metal is not known.

SKIN SENSITIZATION: Considering the widespread use of aluminum, only a very few cases of potential sensitization have been reported and very few details of the cases are available. In one report, 4 cases of contact dermatitis were reported in workers occupationally exposed to aluminum. No information on previous history of allergies was reported. In addition, the possibility of an irritant, rather than allergic, reaction was not excluded. Another case report describes a hospital worker who showed a positive response to aluminum following sensitivity tests. It is not clear that this person was occupationally exposed to aluminum. If aluminum is a true allergen, which is doubtful, the allergy is considered very rare. Negative results have been obtained in animal studies.

RESPIRATORY SENSITIZATION: Cases of asthma-like symptoms have been observed among workers in the aluminum production industry. However, the cause has not been determined, and these workers are potentially exposed to many different airborne substances.

INGESTION: Ingestion of large amounts of aluminum compounds over a prolonged period may cause phosphate deficiency, based on animal and human information. Prolonged ingestion of very large amounts (several grams/day) may result in osteomalacia (softening and bending of the bones). There are no reports of these effects from occupational exposures to aluminum.

Increases in death rates from some types of cancer have been observed in aluminum production, but these effects are believed to be the result of exposure to other substances, not of exposure to aluminum. Cancers have not been observed in animal studies. The International Agency for Research on Cancer (IARC) has concluded that aluminum production is classified as carcinogenic to humans, based on sufficient human information (overall evaluation: Group 1). However, IARC does not suggest that the carcinogenic effect is due to aluminum exposure.

There is no specific information available for metallic aluminum or its insoluble compounds. A soluble aluminum compound (aluminum chloride) has caused slight sperm effects in rats.

There is no specific information available for metallic aluminum. In animal studies, an insoluble aluminum compound (aluminum hydroxide) was not embryotoxic or fetotoxic unless administered in the presence of citric acid, lactic acid or ascorbic acid, in which case there was also maternal toxicity. Very high oral exposure of rats to soluble aluminum compounds has caused fetotoxicity, in the absence of maternal toxicity. It is not known if similar effects would be expected from aluminum or its insoluble compounds. There is no human information available.

There is no information available.

Aluminum is absorbed only to a limited degree from either the gastrointestinal tract or the lungs, and is rapidly excreted in the urine. A certain amount of tissue uptake does occur. The degree of absorption of aluminum following ingestion has been shown to depend on the chemical form of the metal as well as the presence of other dietary constituents such as citrate, ascorbate and lactate. Water solubility has not been found to be a good indicator of the degree of aluminum absorption for different aluminum compounds. In one study, urine aluminum levels increased by between 4 and 50 times following ingestion of antacids containing aluminum hydroxide.