2,2’-Dichloro-4,4’-methylenedianiline (MOCA) is an aromatic amine. It is produced by the reaction of formaldehyde and 2-chloroaniline. It is not produced in Europe. Its import to Europe is estimated at 1 000–10 000 t/year. MOCA has a moderate toxic effect on animals; median lethal doses after oral administration to rodents are 400–1 140 mg/kg bw. It has a moderate irritant effect on the skin and eyes, but no allergenic effect. Data on subchronic and chronic an­imal toxicity indicate multiorgan toxicity. MOCA shows mutagenic and genotoxic potential, both in vivo and in vitro.

No data are available on the effects of MOCA on human reproduction or on the embryotoxicity and teratogenicity. The only rat experiment showed that MOCA has no influence on the reproductive potential of parents, and the growth and the of development of offspring. MOCA has a harmonised classification as Carc.1B. IARC considered that there were was insufficient evidence of MOCA carcinogenicity in humans and sufficient evidence of carcinogenicity in animals. In the overall assessment IARC classified MOCA into group 1 – compound carcinogenic to humans. SCOEL included MOCA to genotoxic carcinogens with non-threshold effect (group A). The values of the current hygiene standards range from 0.22 mg/m³ to 0.005 mg/m³ and are labelled “skin” and “carcinogen”. Furthermore, in many countries, no limit values have been set for MOCA due to its carcinogenicity. Also in the EU, SCOEL did not set a standard value for MOCA. In 2018 the European Commission has proposed to include a limit value of 0.01 mg/m³ as a binding value (BOELV) with the simultaneous notation of ‘skin’ in Annex III to the proposal for a Directive of the European Parlia­ment and of the Council amending Directive 2004/37/EC on the protection of workers from the risks related to exposure to carcinogens or mutagens at work. The MAC value currently in force in Poland (0.02 mg/m³) was derived on the basis of the linear model with the assumed risk of 10^-4. The cancer risk assessment using the two-step model gave the risk values accordingly: 4.6 - 10^-4 for MOCA concentration 0.02 mg/m³ and 1.7 - 10^-4 for 0.01 mg/m³. A similar risk value of 9.65 - 10^-5 (≈ 1 - 10^-4) for inhalation exposure to 0.01 mg/m³ was assigned by RAC using a linear model. In view of the fact that the risk assessments gave compatible values for 0.01 mg/m³ and that the European Union proposed this value as BOELV, it was proposed to use a MOCA concentration in workplace air of 0.01 mg/m³ as the MAC value in Poland. The main route of exposure to MOCA in at occupational conditions is the dermal route. MOCA levels in workers’ urine are a better indicator for overall exposure assessment than measuring MOCA concentrations in work­place air. However, for practical reasons, it was proposed 5 μmol MOCA/mole creatinine in urine collected at the end of the shift as an equivalent to BEI. According to the risk assessment presented by SCOEL, this MOCA concentration in urine leads to a cancer risk of 3–4 - 10^-6. Since dermal exposure accounts for a significant proportion of the MOCA taken by workers, a ‘skin’ notation is required. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

3-Methylbutan-1-ol (isoamyl alcohol, isopentanol) is the primary isomer of pentanol. The compound is a colorless, oily liquid with a characteristic odor. It is formed as a by-product during alcoholic fermentation. Is one of the main components of fusel oil. The compound has found many applications thanks to its dissolution properties: fats, alkaloids, resins, waxes, fragrance oils, synthetic rubber, paints and varnishes. According to the data of the Sanitary and Epidemiological Station in Bydgoszcz, in the years 2016-2017 no worker exposure was reported for concentrations above the MAC-TWA (maximum allowable concentration, eight-hour time weighted average) of 200 mg/m³ or above STEL (short-term exposure limit value) 400 mg/m³. 3-Methylbutan-1-ol has low acute toxicity. In humans and animals, it is irritating to the eyes and mucous membranes of the nasal cavity and has a slight irritating effect on the skin, and in acute exposure it depresses the central nervous system. In vitro studies did not show a mutagenic effect of the compound both under and without metabolic activation. In vivo, single oral administration of the compound to rats caused a slight increase in the incidence of chromosomal aberrations in bone marrow cells. The substance has not been evaluated by the International Agency for Research on Cancer. Animal studies did not show embryotoxic, fetotoxic or teratogenic effects. Based on the results of studies involving volunteers and studies on experimental animals, it was shown that the critical effect of exposure to 3-methylbutan-1-ol is irritation. SCOEL experts proposed OEL and STEL values of 3-methylbutan-1-ol on a much lower level (8-hour TWA: 18 mg/m³, STEL: 37 mg/m³) than the MAC (maximum allowable concentration) values

set in most countries. The proposed values are included in the draft European Commission Directive establishing a 5^th list of Indicative Occupational Exposure Limit values at European Community level under the Chemical Agents Directive (98/24/EC). Assuming the irritating effects as a critical effect of exposure to this compound, the Group of Experts of Chemical Agents proposed the MAC-TWA value of 3-methylbutan-1-ol based on the RD₅₀ value determined in mouse studies (2 639 mg/m³). It is assumed that for compounds with an irritating effect, the MAC-TWA value should be between 1/10 and 1/100 RD₅₀. Due to the uncertainty of the available data, it was proposed to adopt the value 1/100 RD₅₀ to

determine the MAC-TWA value of 3-methylbutan-1-ol, i.e., 26 mg/m³. Due to the irritating effect of the compound, it was proposed to adopt a STEL value of 52 mg/m³ (2 OEL-TWA). The Expert Group for Chemical Agents considered there was no substantive basis to determine the biological exposure index value (BAI). Because of the irritating effects, it has been suggested to label the substance as “I” – irritant. Following a discussion at the 91st meeting of the Interdepartmental Commission for MAC and MAI, TWA and STEL values of 18 mg/m³ and 37 mg/m³, respectively, were adopted. They were set at the level of indicative values included in the Draft European Commission Directive establishing a 5th list of Indicative Occupational Exposure Limit values at European Community level. The proposed values of hygienic standards should protect employees against irritant effects 3-methylbutan-1-ol on the eyes and mucous membranes of the upper respiratory tract, and due to the fact that systemic effects were observed at exposure to significantly higher concentrations/doses, also against systemic effects. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

N-Nitrosodimethylamine is a flammable, volatile, oily liquid with a yellow color and a characteristic odor. It is used in the rubber and leather industry, foundry and agriculture. In Poland, in the years 2005-2016, several dozen to several hundred people per year were exposed on N-nitrosodimethylamine. The highest concentrations to which rubber industry workers in Poland were exposed were 4.5–9.2 μg/m³. Acute poisoning with N-nitrosodimethylamine in humans occurred as a result of accidents or criminal activities. After intragastric administration of N-nitrosodimethylamine to rats, LD₅₀ was below 50 mg/kg bw. Chronic oral exposure (45–52 weeks) of rats to N-nitrosodimethylamine at doses of 0.144–3.6 mg/kg/day resulted in a dose-dependent increase in the cancer incidence of the liver, kidneys and lungs, and shortening of lifespan. Most information about the relationship between the toxic effects and level of exposure comes from an experiment performed on rats, in which N-nitrosodimethylamine was administered chronically in drinking water at doses of 0.001–0.697 mg/kg body weight/day (males) or 0.002–1.244 mg/kg bw./day (females). For doses up to 0.2 mg/kg/day, the risk of liver cancer increased (depending on the dose). N-Nitrosodimethylamine was mutagenic and genotoxic after metabolic activation. This is related to the mechanism of genotoxic and carcinogenic action of the metabolites. The International Agency for Research on Cancer (IARC) has included N-nitrosodimethylamine to 2A group (probably carcinogenic to humans), ACGIH (in 2001) qualified N-nitrosodimethylamine to A3 group (proven carcinogenicity to animals and unknown human carcinogenicity). The European Union has classified the compound with the inscription “H350 - can cause cancer”. The basis for the calculation of a threshold limit value-time weighted average (TLV-TWA; maximum acceptable concentration – MAC) for N-nitrosodimethylamine was the chronic exposure of rats to the compound in drinking water and observed changes in the liver. On the basis of these studies, an assessment of the risk of an additional tumor was made, which has been used to propose MAC-TWA values at 0.0025 mg/m³, for which the cancer risk would be 6.15 × 10^-4. There is no basis for the short-term exposure limit (STEL) or biological limit value (BLV). The notations “Carc. 1B” (carcinogenic substance Cat. 1B) and “skin” (absorption through the skin may be as important as in the case of inhalation) were proposed. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

Phosphoryl trichloride is a clear, colorless or yellowish liquid with an unpleasant, pungent odor. In contact with water or steam, it rapidly hydrolyses by releasing hydrogen chloride and phosphoric(V) acid. Phosphoryl trichloride is used in industry primarily for the production of alkyl and aryl triesters of phosphoric(V) acid. It is also used in the production of plasticizers, flame retardants, hydraulic fluids, insecticides, pharmaceuticals, gasoline additives and dye intermediates. Phosphoryl trichloride is also used as chlorinating agent, pH regulator, catalyst, solvent in cryoscopy, dopant for semiconductor grade silicon, and as reagent in laboratories. Phosphoryl trichloride is classified for acute toxicity as category 2 with inhalation (inhalation may lead to death) and as category 4 if swallowed (harmful if swallowed). In addition, it is classified as corrosive category 1A (causes severe skin burns and eye damage) and toxic to target organs due to repeated exposure, category 1 (causes damage to organs through prolonged or repeated exposure). Both in acute and chronic cases of inhalation exposure, the primary effect was irritating to the respiratory tract and eyes (burning eyes and throat, feeling of breathlessness, tearing, coughing, bronchospasm, pain behind the sternum, pleurisy). In exposed workers, deterioration of pulmonary spirometric parameters was observed. The late effects of exposure were asthmatic problems and obstructive respiratory disease. Available animal studies are poorly documented. Phosphoryl trichloride did not show any mutagenic effects. There is no information on the carcinogenic, embryotoxic or teratogenic effects of this substance in the available literature. The critical effect of the action of phosphoryl trichloride is a strong irritation on the mucous membranes of the eyes and upper respiratory tract. A concentration of 0.48 mg/m³ constituting the threshold for toxic effects of phosphoryl trichloride in studies in rats and guinea pigs was taken as the LOAEC value. After applying the uncertainty coefficients, the MAC value of phosphoryl trichloride calculated on this basis is 0.06 mg/m³. It is proposed to adopt the MAC value in accordance with the SCOEL and ACSH recommendation, i.e., 0.064 mg/m³. Phosphoryl trichloride is a strongly irritating substance, in order to prevent peak concentrations of this substance it is proposed to set the maximum allowable short-term concentration (MAC-STEL) at level 2 × MAC value, i.e., 0.13 mg/m³. There are no substantive foundations to determine the permissible biological exposure indices to phosphoryl trichloride (DSB). Due to the corrosive effect of phosphoryl chloride, it is proposed to label it with the letter “C” (a substance with a corrosive effect). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

PCDD are environmental pollutants, called Persistent Organic Pollutants (POPs). Their trace amounts can be found in almost all the spectrum of global ecosystems. Nearly 90% of human exposure to dioxins comes from food. POPs compounds, which gather in fatty tissues, are slowly metabolized and remain harmful even after a relatively long time after exposure. Dioxins enter the human body with food and accumulate in fat-rich tissues. Dioxins gradually and slowly accumulate in the body. They trigger a number of immunological reactions, which take the form of chronic skin allergies. They can disturb the body hormone economy through induction of the aromatic hydrocarbon receptor. The aim of the work was to develop and validate a sensitive method of determining 2,3,7,8-TCDD in the working environment in the range of 1/10–2 MAC values. The developed method consists in adsorption of TCDD on polyurethane foam followed by extraction of the retained compound with toluene and chromatographic analysis using a high-resolution mass spec­trometry. The determined TCDD desorption coefficient from polyurethane foam with 20% acetone in toluene is 83.1%. The response of the mass detector is linear (r = 0.998) in the concentration range of 18–360 pg/ml, which corresponds to the range of 1.8–36 mg/m³ (1/10–2 MAC) for an air sample of 10 m³. The limit of quantification (LOQ) of this method is 10.26 pg/ml. Using a DB-5MS capillary column makes a selective determination of TCDD in the presence of toluene, nonane and other co-existing compounds possible. The developed method is characterized by good precision and accuracy and meets the requirements of European Standard PN-EN 482 for procedures on determining chemical agents. The deve­loped method of determining TCDD has been recorded as an analytical procedure (see appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.