Ozone from Air

SECTION 2: Hazards identification

EMERGENCY OVERVIEW DANGER! Toxic, oxidizing gas. Harmful or fatal if inhaled. May accelerate combustion. Irritates and may damage eyes, skin, and respiratory system. May cause drowsiness. Symptoms may be delayed Self-contained breathing apparatus and protective clothing must be worn by rescue workers. Odor: Unpleasant, sulfur-like Copyright © 1998, 2000, Praxair Technology, Inc. THRESHOLD LIMIT VALUE Ozone 0.1 ppm TLV-TWA, light work; 0.08 ppm, moderate work; 0.05 ppm, heavy work; heavy, moderate, or light workloads < 2 hr*, 0.20 ppm (ACGIH, 1999). Nitrogen oxides as by-products: Nitric oxide (NO, CAS# 10102-43-9), 25 ppm TLV-TWA (PEL 25 ppm); nitrogen dioxide (NO2, CAS# 10102-44-0), 3 ppm TLV-TWA (PEL, 5 ppm ceiling); nitrous oxide (N2O, CAS# 10024-97-2), 50 ppm TLV-TWA (PEL N/A); nitrogen pentoxide (N2O5, CAS# unk.), N/A. Acids: nitrous acid (HNO2, CAS# 7782-77-6), N/A; nitric acid (HNO3, CAS# 7697-37-2), 2 ppm TLV-TWA (PEL 2 ppm). TLV-TWAs should be used as a guide in the control of health hazards and not as fine lines between safe and dangerous concentrations. *The symbol < means “less than or equal to.” EFFECTS OF A SINGLE (ACUTE) OVEREXPOSURE: INHALATION–Exposure to ozone concentrations above the TLV of 0.1 ppm may irritate the nose and throat, and cause dryness. Pain or congestion in the chest may be accompanied by wheezing and coughing. At concentrations above 0.3 ppm for 30 minutes, particularly in exercising individuals, these symptoms are more likely. Eye irritation, headache, nausea, and alterations in pulmonary function (lung impairment and breathing difficulty) may also occur. At concentrations above 0.9 ppm, respiratory effects worsen and drowsiness may occur. Levels near 9 ppm may cause pneumonia, excessive sweating, decreased blood pressure, and weak and rapid pulse. Death may occur from prolonged exposure at 2 ppm or short exposures (1-4 hours) at 10 ppm. SKIN CONTACT–Contact with ozone may irritate the skin. Nitrogen oxide by-products may combine with moisture in the skin and mucous membranes to form nitrogen acids, producing chemical burns. SWALLOWING–A highly unlikely route of exposure. This product is a gas at normal temperature and pressure. EYE CONTACT–Exposed persons may sense eye irritation at or above the TLV of 0.1 ppm ozone. Exposure to ozone at 2 ppm over 4 hours has caused eye irritation in rabbits. Nitrous oxide is moderately irritating to the eyes and nose at 50 ppm; 25 ppm is irritating to some people. Nitrogen oxide by-products may combine with moisture in the eyes to form nitrogen acids, producing chemical burns. EFFECTS OF REPEATED (CHRONIC) OVEREXPOSURE: Prolonged, low-level (0.3 ppm) exposure to ozone may produce scarring and thickening of small air passages, resulting in chronic lung disease. People with existing lung disease may show earlier and more severe symptoms when exposed to ozone. An increased susceptibility to lung disease and infection may also occur. OTHER EFFECTS OF OVEREXPOSURE: None known for ozone, but see section 16 for effects of nitrogen compounds produced by the breakdown of ozone.

Medical Conditions Generally Aggravated by Exposure

OVEREXPOSURE People with existing lung disease may show earlier and more severe symptoms when exposed to ozone. An increased susceptibility to lung disease and infection may also occur. SIGNIFICANT LABORATORY DATA WITH POSSIBLE RELEVANCE TO HUMAN HEALTH HAZARD EVALUATION: There is limited evidence that ozone in concentrations of over 1.5 ppm may be lethal to rodent embryos. Studies of mutagenic effects in humans have been equivocal. CARCINOGENICITY: Ozone is not listed by NTP, OSHA, and IARC.