Calcium Magnesium Carbonate

Principle Routes of Exposure

Eye contact, skin contact, inhalation, and ingestion. Effects Resulting from Eye Contact: Exposure to airborne dust may cause immediate or delayed irritation or inflammation. Eye contact by large amounts of dry powder or splashes of wet limestone dust may cause effects ranging from moderate eye irritation to corneal abrasions. Such exposures may require immediate first aid (see Section 4) and medical attention to prevent damage to the eye. Effects Resulting from Skin Contact: Direct contact may cause irritation by mechanical abrasion. Effects Resulting from Inhalation: Limestone may contain trace amounts of free crystalline silica. Prolonged exposure to respirable free silica can aggravate other lung conditions and cause silicosis, a disabling and potentially fatal lung disease. Exposure to limestone dust may cause irritation to the moist mucous membranes of the nose, throat, and upper respiratory system. It may also leave unpleasant deposits in the nose. Effects Resulting from Ingestion: Although small quantities of dust are not known to be harmful, ill effects are possible if larger quantities are consumed. Carcinogenic potential: Limestone is not listed as a carcinogen by NTP, OSHA, or IARC. It may however, contain trace amounts of substances listed as carcinogens by these organizations. Crystalline silica, which is a component of limestone, is now classified by IARC as known human carcinogen (Group I). NTP has characterized respirable silica as "reasonably anticipated to be [a] carcinogen". Medical conditions which may be aggravated by inhalation or dermal exposure: Pre-existing upper respiratory and lung diseases.