Direct skin contact

Although metallic antimony may be handled freely without danger, it is recommended that direct skin contact with antimony and its alloys be avoided. Properly designed exhaust ventilation systems and/or approved respirators are required for operations that create dusts or fumes. As with other heavy metals, orderly housekeeping practice and good personal hygiene are necessary to prevent ingestion of (or exposure to) antimony. 

Another difficulty comes from the consideration of the route of entry (sf the contaminant, as chemicals can enter the body by various routes and the human body responds to the action of a toxic agent primarily on the basis of the rate and route of exposure. Without any doubt, the most important route of exposure at the workplace is inhalation, and this should be the route used to set OELs. However, if there is a threat of significant exposure by other routes, such as cutaneously (including mucous membranes and the eyes), either by contact with vapors or by direct skin contact w ith the substance, additional recommendations may be necessary. 

To determine acceptable contaminant levels in soils, two primary exposure routes are usually considered (1) inlialation of gases, vapors, or airborne particulate emanating from the site, and (2) ingestion of contamimtted drinking water. Other routes that can contribute to e.xposure include absorption of pollutants tluough direct skin contact and uptake of wtiter or soil contantinants by plants that are part of the food chain. 

The route of application can be either by oral intake, parenterally or via the air or direct skin contact (contact anaphylaxis) [37]. In spite of great progress in experimental and clinical allergology, anaphylaxis still represents a major problem both for researchers and clinicians. 

Dermal Effects. Humans that were experimentally exposed to 200 ppm of trichloroethylene vapor for 7 hours experienced dry throats (40% of the subjects), begiiming after 30 minutes (Stewart et al. 1970). The subjects experiencing these symptoms did not experience them when exposed in the same manner on 5 other consecutive days. These effects are presumed to be due to direct contact with the vapor. Skin irritation and rashes have resulted from occupational exposure to trichloroethylene (Bauer and Rabens 1974 El Ghawabi et al. 1973). The dermal effects are usually the consequence of direct skin contact with concentrated solutions, but occupational exposure also involves vapor contact. Adverse effects have not been reported from exposure to dilute aqueous solutions. 

Data Adequacy The key study was well designed, conducted, and documented. Values were presented graphically. Supporting data were sparse, probably because aniline is not a vapor at room temperature, and poisonings have involved contact with the liquid. Although human data are sparse, it is believed that a total uncertainty factor of 100 is protective of human health. Because aniline is absorbed through the skin, which increases the systemic toxicity, direct skin contact with the liquid would be additive and result in onset of adverse effects at airborne concentrations below the respective AEGL values. Therefore, direct skin contact with the liquid should be avoided. 

Skin Notation. Substances on the list followed by the designation Skin refer to the potential significant contribution to the overall exposure by the skin route, including mucous membranes and the eyes, either by contact with vapors or, of probable greater significance, by direct skin contact with the substance. 

Occupational exposure of 12 male workers, whose hands were in contact with MDA several hours per day, caused toxic hepatitis. The clinical pattern of the cases included right upper quadrant pain, high fever, and chills with subsequent jaundice. A skin rash was seen in five of the cases. Percutaneous absorption was considered to be the major route of exposure because workers in the same occupational setting who did not have direct skin contact with MDA were not affected. All patients recovered within 7 weeks, and follow-up more than 5 years later showed no biochemical or clinical evidence of chronic hepatic disease. 

You may be exposed to hexachlorobutadiene by breathing contaminated air, eating contaminated food, drinking contaminated water, or by direct skin contact with this chemical. People working in the industrial facilities where hexachlorobutadiene is formed or used may be exposed. Concentrations found in outside air were 2-3 parts hexachlorobutadiene per trillion parts of air (ppt). Levels were much higher in or near industrial facilities where hexachlorobutadiene is formed or used. One survey detected air concentrations ranging from 22 to 43,000 ppt in a production facility. No information is available on how many workers are potentially exposed to hexachlorobutadiene. 

No information exists for either animals or humans on toxic effects following oral exposure (Tables 1-3 and 1-4), but oral exposure is of little concern since BCME breaks down in water or moist foods and exposure is not likely by this route. Direct skin contact with even small amounts (less than a drop) of the liquid form of BCME causes severe skin irritation at the site of contact. Further information on the exposure levels that have been found to cause harmful health effects in humans and animals is presented in Chapter 2. 

Toxicity Studies by Cheever et al.31,41,45 have indicated that n-Butylamine has caused toxicity to animals. The acute oral LD50 of male and female Sprague Dawley rats is 371 mg/kg. The vapors of n-Butylamine cause irritation to eyes and mucous membranes, as well as irritation and blistering effects to the skin of animals and humans.31,41,45 Workers exposed by direct skin contact to the liquid form demonstrated severe irritation of the skin in addition to deep second-degree bums and blistering. 

Inhalation and direct skin contact are the most common routes of exposure. Since potent compounds tend to be handled in solid/powder or liquid form, control measures need to be used to prevent dust or liquid aerosols from becoming airborne, and subsequently being inhaled or coming into contact with the skin. In addition to inhalation, direct skin contact and inadvertent contact with powders or liquids are routes of exposure that need to be identified and minimized. 

Inhalation and direct skin contact are the most common routes of chemical exposure. The greatest exposure risk in handling potent compounds in an analytical laboratory therefore occurs when handling solid materials due to the potential to generate and inhale airborne dust particles of the compound. Once the potent material has been placed into solution, the airborne exposure risk is reduced and solutions of potent compounds may be handled in a manner similar to other nonpotent pharmaceutical compounds, assuming good laboratory practices are followed. Caution should be taken not to aerosolize the solutions since this could create an inhalation hazard. In addition, any sample solution spills should be adequately cleaned to prevent powder deposits of the compound from forming, which could potentially become airborne after the liquid has dried. 

Amines are toxic chemicals. Avoid excessive inhaling of the vapors and use gloves to avoid direct skin contact. Anilines are more toxic than aliphatic amines and are readily absorbed through the skin. Wash any amine or aniline spill with large quantities of water. Diethyl ether (ether) is extremely flammable. Be certain there are NO open flames in the immediate area. 

The only studies located regarding health effects in humans after inhalation exposure to tetryl were case studies and other reports of workers exposed to tetryl dusts in manufacturing plants during World War I and World War II. Little information was available regarding the number of people exposed or the duration and level of exposure. Since exposure was to the tetryl-laden dusts, the effects could have been caused by inhalation, direct skin contact, or by swallowing. The dermal effects noted in these studies were most likely caused by direct skin contact and are described in Section 2.2.3. It is unknown whether the other effects were caused by inhaling or by swallowing tetryl therefore, in this profile, it is assumed that the primary route of exposure was inhalation. 

No studies were available regarding cardiovascular, musculoskeletal, renal, dermal or ocular effects in humans after inhalation exposure to tetryl. Dermal effects, presumably from direct skin contact, are described in Section 2.2.3.2. No studies were located regarding systemic effects in animals after inhalation exposure to tetryl. The systemic effects that have been observed after inhalation exposure in humans are described below. 

Based on an observational study of workers in a tire factory, it was estimated that a worker exposed to benzene as a result of direct skin contact with petroleum naphtha containing 0.5% benzene could absorb 4-8 mg of benzene per day through intact skin (Susten et al. 1985). This amount absorbed was compared with an estimated 14 mg of benzene absorbed as a result of inhalation of 1 ppm for an 8-hour day. The estimate for dermal absorption is exaggerated since in many facilities the concentration of benzene in rubber solvents such as petroleum naphtha is less than 0.5% and may be as low as 0.09%. 

Toxicity and health effects Studies have shown that exposure to vapors causes irritation to the eyes, severe burns, loss of vision, irritation to the nose and throat, headache, and pulmonary edema. Exposure to excessive vapor concentrations may cause nausea, vomiting, fainmess, coughing, chest pains, dizziness, depression, convulsions, narcosis, and possibly unconsciousness. Exposure of this nature is unlikely, however, because of the irritating properties of the vapor. Any direct skin contact with liquid -butylamine causes... 

Allergic dermatitis has been demonstrated from direct skin contact and from exposure to gaseous formaldehyde in the air. Various forms of reaction occur, from simple erythema to maculopapular lesions, hyperesthesia, and angioedema. Five patients developed an allergic contact dermatitis to plaster casts, caused by free formaldehyde released by a melamine-formaldehyde resin incorporated in the plaster. 

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