2-Butanone is a colourless liquid with a characteristic odour. The nervous system and liver are critical organes in animals’ 90-day exposure to 2-butanone. The MAC (TWA) value was calculate on the basis of the NOAEL value (7500 mg/m3) for systemic effects in rats. A MAC (TWA) value at the level of 450 mg/m³ was established. Because of the irritant effect of of this compound a MAC-STEL value of 900 mg/m³ was suggested. The “I” (irritation substance) notation and “Sk” (substance absorbed through the skin) were proposed. We suggest accepting a BEI value on the level of 1.5 mg of 2-butanone/litre of urine.

Tetraphosphorus decaoxide (TD) is a white solid with a weak phosphorous odor. It is strongly hydroscopic. Tetraphosphorus decaoxide is used in the production of phosphorus oxychlorides, acrylic esters, surface active substances and special glassware. Tetraphosphorus decaoxide is a strong irritant for the respiratory tract, skin and eyes. It is a corrosive substance. There are no data about chronic toxicity or delayed effects. The proposed maximum exposure limit MAC (TWA) of 1 mg/m³ is based on an epidemiological study of 131 workers employed for 3 to 46 years mining phosphorous ore. No decrease of pulmonary respiration efficiency in the workers was stated during observation the period of 3 to 7 years. The proposed MAC (STEL) value is 2 mg/m³, because tetraphosphorus decaoxide is a strong irritant.

Diisopropyl ether (CAS No 108-20-3) is a liquid with a characteristic odour. This substance is used as a solvent for oils, fats, waxes, resins, dyes and paints. It is used to produce varnishes, inks, in synthesis of fuels, cosmetics and pharmaceuticals. In animals diisopropyl ether is characterized by low acute toxicity: oral LD50 values in rats ranged from 4600 to 11600 mg/kg, and LC50 from 121000 to 162000 mg/m³. Death was due to respiratory failure caused by depressant action. Acute exposure of human to diisopropyl ether at a concentration of 3350 mg/m³ reported irritation of the eyes and nose. After repeated 20-day exposure of animals to diisopropyl ether at concentrations between 4000 and 13000 mg/m³ there were no toxic effects. Monkeys exposed repeatedly (20 days, 1 h daily) at a vapor concentration of 41700 mg/m³ exhibited intoxication and depression of the central nervous system. This concentration is LOAEL for monkeys and NOAEL for rabbits and guinea pigs. 90-day exposure of rats to diisopropyl ether at a concentration of 14900 mg/m³ caused an increase in liver and kidney weight in males. These effects in females were noted at a concentration of 32600 mg/m³. Diisopropyl ether did not display mutagenic, clastogenic and cancerogenic effects. There was no evidence of fetotoxic anf teratogenic effects. Diisopropyl ether is rapidly absorbed by the blood from the lungs or the gastrointestinal tract. A major portion of a dose is eliminated through the lungs. Experimental data suggest that there is no basis for the verification of the MAC value (1000 mg/m³) for diisopropyl ether. No STEL and BEI values have been proposed.

1,3-Ethylenethiourea (ETU) is used primarily as an accelerator for vulcanising polychloroprene and polyacrylate rubbers. Occupational exposure to 1,3-ethylenethiourea occurs also in the chemical industry where it is used as an intermediate in dyes, synthetic resins and pharmaceuticals synthesis. It is also a metabolic degradation prod-uct and an impurity in ethylenebisdithiocarbamate fungicides, and field workers may be exposed to 1,3-ethyle-nethiourea while applying these fungicides. The primary routes of potential human exposure to 1,3-ethylenethiourea are inhalation, ingestion and dermal contact. The principal toxic effects of 1,3-ethylenethiourea in humans involve the thyroid gland. 1,3-Ethylenethiourea is a harmful substance in laboratory animals in acute toxicity testing. In chronic toxicity it exerts harmful action on thyroid glands and the liver. 1,3-Ethylenethiourea did not show genotoxicity in many experimental studies. In carcinogenicity testing this compound induced thyroid follicular cell carcinoma in rats of both sexes, and thyroid follicular cell neoplasms, hepatocellular neoplasms, and adenomas of the parts distalis of the pituitary gland in both sexes of mice. There are no data on carcinogenicity in humans. 1,3-Ethylenethiourea exerts embryotoxic, fetotoxic and teratogenic effects in animals. The MAC (TWA) value has been calculated at 0.1 mg/m3 on the basis of the results of human exposed to 1,3-ethy-lenethiourea. In workers exposed to 1,3-ethylenethiourea in 0.2 mg/mm³ concentrations for 10 years, significant serum levels of thyroxine (T4), but no changes in the level of thyroid-stimulating hormone was observed. The concentration 0.2 mg/m³ is considered as NOAEL. No STEL value has been established. With regard to fetotoxic effects of 1,3-ethylenethiourea in laboratory animals an “Ft” notation is considered appropriate.

Cresol is a liquid which consists of its three isomers, i.e. o-, m-, and p-cresol. It is used as a disinfecting and preserving agent and as an intermediate in organic synthesis. Occupational exposure to cresols may occur in coke plants, the petrochemical and chemical industry, foundry work and during other industrial activities. Cresols exert toxic effects on the central nervous system, respiratory system, peripheral blood, skin, mucous membranes, liver, and kidneys. These chemicals are classified as toxic and corrosive substances. Cresols demonstrate clastogenic and tumor promotion activity. They exert an adverse effect on reproduction in a multigeneration model. The MAC (TWA) value was calculated on the basis of LOAEL value (for an increase in the concentration of bile in bile and histological changes in nasdal mucosa) in rodents. A MAC (TWA) value at the level of 22 mg/m³ was proposed. Skin (“Sk”) and corrosive (“C”) notations are recommended.

This method is based on the adsorption of desflurane on petroleum charcoal, desorption with toluene and a gas chromatographic (GC-MSD) analysis of the resulting solution. The determination limit of the method is 4 mg/m³.

This method is based on the collection of diethyl ether in Tedlar® air bags and a direct gas chromatographic analysis of the air in the collecting bag using a flame ionization detector (GC-FID). The determination limit of the method is 100 mg/m³.

Air samples are collected by drawing a known volume of air through glass fiber filters (37 mm). The filtres are transferred into vials and benzyl butyl phthalate is extracted with carbon disulfide. The obtained extracts are analyzed by gas chromatography with a flame ionization detector (GC-FID). The determination limit of the method is 0.5 mg/m³.

This method is based on the adsorption of isoflurane on petroleum charcoal, desorption with toluene and a gas chromatographic (GC-MSD) analysis of the resulting solution. The determination limit of the method is 1 mg/m³.

The determination method is based on the adsorption of volatile organic compounds (VOCs) on activated charcoal (200/50 mg sections), desorption with 1 ml of 1% (v/v) methanol in carbon disulfide and a gas chromatographic with flame ionization detection (GC-FID) analysis of the resulting solution.

Air samples are collected by drawing a known volume of air through sorbent tubes filled with silica gel coated with dinitrophenylhydrazine. The resulting derivatives of n-pentanal are eluted with 10 ml of acetonitrile to volumetric flasks. The obtained solutions are diluted with acetonitrile and analyzed by high performance liquid chromatography using ultraviolet detection (λ = 360 nm). The working range of the analytical method is from 0.1 to 20 μg/ml (2 ÷ 400 mg/m³ for a 5 l air sample).