Skin-Contact Toxicity

Skin-Contact Toxicity Data for acute (short-term) exposures of the skin to corrosive and toxic liquids, solids, and gases are extremely limited, particularly where the consequences are severe or fatal injury and the available data may not be useful, from an engineering standpoint. For example, the skin toxicity of hydrogen peroxide to rats is stated as 4060 mg/kg, but the skin area and duration of exposure are not stated. Thus, it is not possible (with the available data) to estimate the relationship among percent of body surface exposed to a corrosive material, the concentration of the corrosive material, the duration of exposure (before removal of the corrosive material), and the severity of the effect. 

Up to now, the TTC concept has only been developed and used for systemic effects following oral exposure (dietary uptake). For industrial chemicals, the predominant exposure is to workers and consumers via inhalation and/or by skin contact. Toxic endpoints of concern for industrial chemicals such as irritation and sensitization relevant for skin and lung are therefore not covered by the TTC concepts developed up to now. 

SAFETY PROFILE Moderately toxic by intraperitoneal, subcutaneous, and intravenous routes. Low oral and skin contact toxicity. A flammable liquid when exposed to heat or flame can react with oxidizing materials. Slight explosion hazard in the form of vapor when exposed to flame. To fight fire, use foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes. See also IRON COMPOUNDS. 

SAFETY PROFILE Low oral and skin contact toxicity. A skin irritant. A flammable liquid. When heated to decomposition it emits acrid smoke and irritating fumes. 

Flammable liquid flash point 37°C (100°F) (Sax 1996) stable at room temperature but explodes when exposed to flame or heated to >90°C (194°F) LEL 1.8% explodes with tetrachlorotrifluoromethylphosphorane under vacuum at ambient temperature highly toxic by ingestion moderately toxic by skin contact toxic effects are those of lead oral LD50 (rat) 105 mg/kg TLV-TWA... 

Acrolein is highly toxic by skin absorption. Brief contact may result in the absorption of harmful and possibly fatal amounts of material. Skin contact causes severe local irritation and chemical bums. Poly(vinyl chloride) coated protective gloves should be used (99). 

These salts are corrosive and are to be considered toxic because of the presence of Ag+ ions. The American Conference of Government Industrial Hygienists (ACGIH) (1992—1993) has adopted TWA values of 0.01 mg/m for silver metal and 0.01 mg/m for soluble silver salts. TWA for fluorides as F ions is 2.5 mg/m. The MSDS should be consulted prior to use. Skin contact and inhalation should be avoided. 

Toxicity studies on trifluoroethanol show acute oral LD q, 240 mg/kg acute dermal LD q, 1680 mg/kg and acute inhalation L(ct) Q, 4600 ppmh. Long-term subchronic inhalation exposure to 50—150 ppm of the alcohol has caused testicular depression in male rats, but no effects were noted at the 10 ppm level (32). Although the significance of the latter observations for human safety is unknown, it is recommended that continuous exposure to greater than 5 ppm or skin contact with it be avoided. 

Exposure to PTFE can arise from ingestion, skin contact, or inhalation. The polymer has no irritating effect to the skin, and test animals fed with the sintered polymer have not shown adverse reactions. Dust generated by grinding the resin also has no effect on test animals. Formation of toxic products is unlikely. Only the heated polymer is a source of a possible health hazard (120). 

Health nd Safety Factors. Isophorone is considered moderately toxic by ingestion and skin contact. Some rat tumor formation evidence has been found (264), but no demonstration as a human carcinogen has been proven. Isophorone is considered an Environmental Protection Agency (EPA) priority pollutant, and has a permissible acute toxicity concentration of 117, 000 ///L to protect freshwater aquatic life, 12, 900 ///L to protect saltwater aquatic life, and 5, 200 ///L to protect human life (265). Isophorone is mildly toxic by inhalation, but because of its low volatiUty it is not a serious vapor hazard. 

Workers in the metals treatment industry are exposed to fumes, dusts, and mists containing metals and metal compounds, as well as to various chemicals from sources such as grinding wheels and lubricants. Exposure can be by inhalation, ingestion, or skin contact. Historically, metal toxicology was concerned with overt effects such as abdominal coHc from lead toxicity. Because of the occupational health and safety standards of the 1990s such effects are rare. Subtie, chronic, or long-term effects of metals treatment exposure are under study. An index to safety precautions for various metal treatment processes is available (6). As additional information is gained, standards are adjusted. 

Methanol is not classified as carcinogenic, but can be acutely toxic if ingested 100—250 mL may be fatal or result in blindness. The principal physiological effect is acidosis resulting from oxidation of methanol to formic acid. Methanol is a general irritant to the skin and mucous membranes. Prolonged skin contact with methanol vapor or Hquid can cause dermatitis. Methanol vapor can cause eye and respiratory tract irritation, nausea, headaches, and dizziness. 

Oxahc acid is not flammable but its decomposition products, both formic acid and carbon monoxide, are toxic and flammable. Its dust and mist are irritating, especially under prolonged contact. Personnel who handle oxahc acid should wear mbber gloves, aprons, protection masks or goggles, etc, to avoid skin contact and inhalation. Adequate ventilation also should be provided in areas in which oxahc acid dust fumes are present. 

Dusts associated with these oxidising compounds produce caustic irritation of skin, eyes, and nasal membranes. Appropriate protection should be worn when handling. Skin contact should be treated as for any caustic material, ie, flush with water and neutralize. Toxicity is low to moderate and is the same as for the hydroxides. Toxicity of the chlorate is greater than for the peroxides and superoxides, and the chlorate material also causes local irritation. 

Monoethan olamine and monoisopropan olamine may be moderately toxic by absorption through the skin. The other amines are low in toxicity by this route and are not likely to be absorbed in acutely toxic amounts. In the event of skin contact, clothing and shoes should be removed promptly, and the skin thoroughly washed with water. Contaminated clothing should be thoroughly cleaned before reuse shoes and leather products should be discarded. 

Toxicology. Isoquinoline is a poison when ingested or injected intraperitoneally. Even in cases of skin contact it is moderately toxic. As in the case of quinoline, its vapors are irritating to the eyes, nose, and throat. Exposure causes headaches, dizziness, and nausea. Rapid absorption through the skin makes it a dangerous chemical. Its toxicity is oral LD q (i t)> mg/kg, and dermal LD q (rabbit), 590 mg/kg (65,66,182,183). 

Rosin has a low order of toxicity foUowing ingestion or skin contact. Rosin and its numerous derivatives have a number of permitted food packaging and other direct and indirect food contact uses throughout the world. Sanctioned uses appHcable in the United States are outlined in U.S. Food and Dmg Administration (U.S. FDA) Regulations (2). Material Safety Data Sheets (MSDSs) for specific rosins and thein derivatives should be consulted before thein use. 

Fig. 3. Schematic representation showing the anatomical basis for differences in the quantitative supply of absorbed material to the Hver. By swallowing (oral route), the main fraction of the absorbed dose is transported direcdy to the Hver. FoUowing inhalation or dermal exposure, the material passes to the pulmonary circulation and thence to the systemic circulation, from which only a portion passes to the Hver. This discrepancy in the amount of absorbed material passing to the Hver may account for differences in toxicity of a material by inhalation and skin contact, compared with its toxicity by swallowing, if metaboHsm of the material in the Hver is significant in its detoxification or metaboHc activation.

Inhalation of 3,000 ppm benzene can be tolerated for 0.5—1 h 7,500 ppm causes toxic effects in 0.5—1 h and 20,000 ppm is fatal in 5—10 min (123). The lethal oral dose for an adult is approximately 15 mL (124). Repeated skin contact is reported to cause drying, defatting, dermatitis, and the risk of secondary infection if fissuring occurs. 

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