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1-Bromopropane .Documentation
Anna Świdwińska-Gajewska, Małgorzata Kupczewska-Dobecka
1-Bromopropane (1-BP) is a clear, colorless liquid. 1-BP is a substitute for solvents, used to clean metals and electronics, in adhesives and coatings applications, and in aerosol propellant applications. 1-Bromopropane is used to replace chlorinated solvents in vapor degreasing and cold metal cleaning operations. This substance is neurotoxic, hepatotoxic, and reproductive in developmental toxicity in animals. Human studies with 1-bromopropane have not been reported except a case study of 1-BP exposed worker who developed polyneuropathy. 1-BP was mutagenic with or without metabolic activation toward Salmonella typhimurium tester strains TA1535 and TA100 but it was not mutagenic towards strains TA1535, TA1538 and TA98. An increase in micronuclei was not observed in Swiss mice. 1-BP did not induce dominant lethal mutations in Sprague-Dawley rats. There are no data about carcinogenicity of this substance. Hepatotoxicity is used as critical effect to calculate maximum admissible concentration to 1-BP. The no-observed-effect (NOEL) for hepatotoxicity in the chronic rat study was 1000 mg/m³. MAC (NDS) of 42 mg/m³ was established. STEL (NDSCh) was not proposed because irritating properties of this substance were observed at concentration as high as 348 mg/m³. Ft notation which indicated that 1-BP is reproductive in developmental toxicity was signed.
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1,6-Hexamethylene diisocyanate (HDI). Documentation
Krystyna Sitarek
1,6-Hexamethylene diisocyanate (HDI) is a colourless liquid with a sharp odour. It has universal industrial use; it is used to produce polyurethanes, elastomers, synthetic gum, anticorrosive preparations, paints and varnishes.
There are few data on the toxicity of this substance. According to available information, it is absorbed in the respiratory tract and eliminated mainly in urine. HDI is irritating on the upper respiratory tract and on eyes; it also causes hypersensitivity of bronchi. HDI induces an allergic reaction of the skin. 1,6-Hexamethylene diisocyanate does not induce mutation in tests with Salmonella typhimurium and does not increase the frequency of micronuclei in erythrocytes of mice. HDI is not a reproductive and development toxin and is not a carcinogen for rats.
The Expert Group for Chemical Agent suggests the following hygienic norms of 1,6-hexamethylene diisocyanate: TLV – 0.04 mg/m³ and STEL – 0.08 mg/m³, “I”– an irritating sub-stance and "A” – a sensitizating substance.
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Toluene-2,4 or 2,6-diisocyanate and the mixture of TDI isomers. Documentation
Renata Soćko, Sławomir Czerczak
Toluene-2,4 and 2,6-diisocyanate (2,4-TDI; 2,6-TDI) are colorless to pale yellow liquids with a sharp acrid odor. 2,4-TDI and 2,6-TDI are two commonly used isomers of toluenediisocyanate (TDI). A commercial mixture of TDI isomers (80% 2,4-TDI, 20% 2,6-TDI) is one of the isocyanates most often employed in the manufacture of ”foamed in place” polyurethane plastics, coatings, and elastomers. The finished products range from soft and sponge-like to hard and porous. The finished polymeric foams are biologically inert and widely used in furniture, packaging, insulation, and boat building and have many other applications. Polyurethane coatings have many desirable properties for use on leather, wire, tank linings and masonry.
Industrial experience has demonstrated that acute exposure to TDI vapors can produce severe irritant efects on mucous membranes, the respiratory tract, and the eyes, and an acute attact of an asthma-like syndrome may occur. Exposure to high concentrations may lead to chemical pneumonitis, pulmonary edema, headache, and insomnia.
The Export Group recommended, on the basis of the results of a human chronic and epidemiological stydy, a TLV value for toluene-2,4 or 2,6-diisocyanate and the mixture of TDI isomers 0,007 mg/m³ and the value of 0,021 mg/m³ as the Short-Term Exposure Limit (STEL). The proposed values of hygiene standards should protect workers against irritating and sensitizing effects of TDI mainly on the respiratory tract and skin. For the same reason, TDI isomers and their mixtures should be denoted with “I” and “A” respectively.
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Epoxyethane. Documentation
Krystyna Sitarek, Wiesław Szymczak
Epoxyethane (ethylene oxide) is a colourless flammable gas at room temperature with a sweet odour. It has been classified as a category 2 carcinogen and mutagen. Epoxyethane is irritating on the skin and mucous membranes. In the past it was used in hospital sterilization, and also in fumigation of food, clothes, cosmetics and furniture.
The main symptoms of acute inhalation toxicity in human are headaches, nausea and generally persistent periodic vomiting. Dyspnoea, irritation of the eyes and upper respiratory mucosa, heart damage, excitation, stupor, vertigo and loss of consciousness have also been observed. Epoxyethane in contact with te skin causes itching, erythema and oedema, blisters and frostbite. Chronic inhalation of human leads to multiple neuropathy, sensory disturbance as well as the damage of vision (corneal clouding).
Acute toxicity to animals – LD50 per os for rats was determined as 330 mg/kg. The 4-hour LC50 for the rat was determined as above 2500 mg/m³.
In animal exposure to epoxyethane in lethal concentrations, the symptoms were lacrimation, nasal discharge, disorders of locomotive coordination, depression of the central nervous system and paralysis (particularly of the hind-quarters).
Ethylene oxide is a weak alkylating agent that is directly mutagenic and carcinogenic. It is also genotoxic and clastogenic. Epoxyethane adducts with haemoglobin, what should be used for biomonitoring of exposed persons.
The carcinogenicity of epoxyethane is clearly evident from animal experiments. In rats it has induced brain tumours, mononuclear cell leukaemias and peritoneal mesotheliomas; in mice lung adenomas and carcinomas. In humans it has induced stomach cancer and leukemia, but this has not been sufficient to classify epoxyethane as a confirmed human carcinogen. For women exposed occupationally to ethylene oxide an increased incidence of spontaneous abortion has been established. In animals it has disordered the reproduction in dose toxic to dams.
Epoxyethane is readily taken by lung and the digestive tract and the main route of its elimination from the organism is the urinary tract. Ethylene glycol is the major metabolite of epoxyethane in mammalians.
In most countries the occupational exposure limit for epoxyethane is 1.8 mg/m³. In Poland MAC(TWA) = 1 mg/m³ and MAC(STEL) = 3 mg/m³.
The Expert Group proposed not to change the MAC(TWA) for epoxyethane (1 mg/m3) and not to establish MAC(STEL), because the irritation in humans occupationally exposed to this substance was observed after exposure above 6 mg/m³.
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Ethyl benzene. Documentation
Renata Soćko, Sławomir Czerczak
Ethyl benzene is a colorless, flammable liquid with an aromatic odor. Ethyl benzene is used as a solvent, as an intermediate in the production of styrene, and in the plastics and rubber industries. Industrial grade xylene contains approximately 20% ethyl benzene.
Ethyl benzene is an irritant of the skin and mucous membranes and appears systemically to have acute and possibly chronic effects on the central nervous system. Other chronic health hazards, as evidenced in animal experimentation, would be damage to the liver, kidneys, and testes.
The Expert Group for Chemical Agents recommended, on the basis of the results of a human inhalation study, a TLV value for ethyl benzene 200 mg/m³ and the value of 400 mg/m³ as the Short-Term Exposure Limit (STEL). The proposed values of hygiene standards should protect workers against the effects of ethyl benzene mainly on the central nervous system as well as potential liver and kidneys damage. The values should minimize the potential for eye and skin irritation. Ethyl benzene should be denoted with “Skin” notation.
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Formamide. Documentation
Agnieszka Jankowska, Sławomir Czerczak
Formamide is a colourless and odourless liquid. This substance is widely used as a solvent in the industry as well as an additive for drilling muds, aircraft deicing fluids and hydraulic fluids. Respiratory tract and skin are the major routes of occupational exposure to formamide. Slight skin and eye irritation was reported in animal studies. Formamide did not produce allergic skin sensitisation. A study in rats treated for 3 months with formamide under semi-occlusive patches to the skin produced systemic toxicity. Rats exposed for 14 days at 920 mg/m³ of formamide vapor had suppressed platelet and lymphocyte counts. In animals exposed at 2760 mg/m³ a decreased rate of body weight gain and microscopic lesions in the kidney (necrosis of tubular epithelium) were observed. Effects on reproduction were seen at 750 ppm of formamide in drinking water in a two-generation study in mice. Formamide showed embryotoxicity and developmental toxicity in animals following dermal, per os and intraperitonealy exposure. In setting the exposure limit, the results of a 14-day inhalation study in rats were considered. Based on the NOAEL value of 184 mg/m³ and appropriate uncertainty factors, a MAC value was calculated at 23 mg/m³. Considering evidence on skin absorption an additional determination with Sk letters was proposed. With regard to the fetotoxic effects of formamide in laboratory animals an Ft notation was considered.
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