Benzene-1,2,4-tricarboxylic acid 1,2-anhydride. Documentation Anna Pałaszewska-Tkacz, Sławomir Czerczak Ethyl cyanoacrylate. Documentation Renata Soćko, Sławomir Czerczak  Cobalt. Documentation Andrzej Sapota, Adam Daragó Sulfuric acid (VI). Documentation Daria Pakulska, Sławomir Czerczak Trichloroacetic acid. Documentation Agnieszka Jankowska, Karolina Bystry, Sławomir Czerczak Nitroethane. Documentation Andrzej Sapota, Małgorzata Skrzypińska-Gawrysiak  Hydrogenated terphenyls. Documentation Krystyna Sitarek  Tributyltin compounds(IV). Documentation Andrzej Starek

 Benzene-1,2,4-tricarboxylic acid 1,2-anhydride. Documentation
Anna Pałaszewska-Tkacz, Sławomir Czerczak

Benzene-1,2,4-tricarboxylic acid 1,2-anhydride is a white crystal solid produced by the oxidation of pseudocumene to form trimellitic acid, this being subsequently dehydrated. It is mainly used in the synthesis of plasticizers for polyvinyl chloride resins, used subsequently in the production of wire and cable coatings, car interior linings and medical equipment parts. Moreover, it is used in the production of polyester resins for water and solvent-based paints and coatings (including anticor-rosive ones), and resins for the production of powder coatings. Trimellitic anhydride is also used as a binding agent for glass fibres, sand and other aggregates and as a plasticizer in materials used to store and cover food.
In 2000, the worldwide production of trimellitic anhydride was over 100 000 tonnes, including 65 000 tonnes produced in the USA. According to available data, there are two producers of tri-mellitic anhydride within the EU, located in the UK and Italy, and one in the USA.
As far as occupational exposure to trimellitic anhydride is concerned, the inhalation route is more significant than dermal exposure.
Results of environmental animal studies revealed that trimellitic anhydride is a chemical of rela-tively low toxicity, regardless of exposure length and route. Results of both epidemiological and animal studies confirm sensitizing activity of this chemical in the contact with skin and respiratory tract and partly its irritating activity to the respiratory system. EU experts have classified trimellit-ic anhydride as a substance irritating to the respiratory system, posing a risk of serious damage to the eyes and potentially causing sensitization by inhalation and skin contact.
In Poland there is no OEL value. Because of shortage of data suitable for establishing OEL, it has been proposed to accept the values of 0.04 mg/m³ as TWA and 0.08 mg/m³ as STEL, similarly to most European countries. It has been also proposed to label the substance with ‘A’ (sensitizer) and ‘I’ (irritant) letters in the Polish OEL list.

Ethyl cyanoacrylate. Documentation
 Renata Soćko, Sławomir Czerczak

Ethyl cyanoacrylate is a clear, colorless liquid with an unpleasant, irritating, acrid odor. Ethyl cyanoacrylate is used as an adhesive to bond a variety of materials, e.g., glass, metal, plastic, rubber, and biological tissue. It has many industrial and domestic applications as polymerization takes place within seconds upon contact without requiring heat or a catalyst. Ethyl cyanoacrylate is a strong local irritant affecting the eyes and the mucous lining of the nose, throat, and upper respiratory tract. Skin contact can cause adhesions resulting in mechanical damage, inflammation, and necrosis to the tissues affected. Ethyl cyanoacrylate is not mutagenic with or without metabolic activation. Ethyl cyanoacrylate adhesives have produced allergic contact dermatitis and asthma in users. On the basis of the results obtained after occupational exposure of human to ethyl cyanoacrylate in concentration of 4.6 mg/m³ (LOAEL), which caused irritant effects, the MAC value for ethyl cyanoacrylate was established at 1.0 mg/m³ and the value of STEL at 2.0 mg/m³. ‘’I’’ – an irritating substance is an additional notation.

 Cobalt. Documentation
Andrzej Sapota, Adam Daragó  

In most compounds, cobalt (Co) occurs at level II or level III of its value. Co compounds (III) react with different acids, producing salts, whereas the reactivity of Co II is less pronounced. This element, present in living organisms, is a microelement and is a component of vitamin B12. It is an essential component of alloys used in high-speed-cutting steel tools (alloys containing 45–50% of Co and 25–30 % of chromium), hard magnets, hard tools and others. Co compounds are used in the production of paints (Thénard blue, smalt) and lacquers in the glass-making and ceramic industries.
In industrial conditions, fumes and dusts are the major sources of exposure. It is estimated that in Poland about 5000 persons are exposed to cobalt and its compounds. In 2000, an excessive exposure of workers to metallic Co (fumes and dusts) was found in a plant in the Silesian voivodeship. Twen-ty persons involved in the manufacture of ready-made metallic products (except for machines and other devices) were exposed; however, according to 2007 data provided by the Chief Sanitary In-spectorate, Co (fumes and dusts) maximum admissible concentrations (MAC = 0.05 mg/m³) were not exceeded.
In the literature there are no data on Co acute intoxications in humans. Non-occupational chronic intoxications due to consumption of large quantities of cobalt sulfate fortified beer induced myocar-dial lesion, enhanced red blood cell count (polycythemia) and disturbed thyroid metabolism. In persons exposed to cobalt via inhalation and absorption through the skin, allergies and irritations are observed. The respiratory tract is its major target organ, hence asthma- and allergy-like lesions, as well as functional changes, involving the impairment of lung functions are most frequent.
On the basis of the results of acute toxicity studies, cobalt and its inorganic compounds can be classi-fied as toxic or hazardous agents. Studies of chronic effects showed that inflammatory and necrotic lesions of respiratory epithelium are the main consequences of cobalt toxicity, and fibrosis of the lower parts of the respiratory tract can also be induced in the case of higher doses. The National Toxicology Program studies have evidenced carcinogenic effect of cobalt sulfate and the Internation-al Agency for Research on Cancer (IARC) has categorized cobalt and its compounds as group 2B (sufficient evidence of carcinogenicity in experimental animals and inadequate evidence in humans).

 Sulfuric acid (VI). Documentation
Daria Pakulska, Sławomir Czerczak

Sulfuric acid (VI) is one of the strongest mineral acids. It is a heavy, oily, colorless liquid that has a very wide range of applications in many industrial sectors. Exposure can occur both to the liquid and to sulphuric acid mists. The most important effects of human exposure to excessive amounts of sulfuric acid are caused by its irritative and corrosive properties. In terms of work settings, dermal contact and inhalation of its mists or sulfur trioxide, which occur during many industrial processes, are the main routes of exposure. The effect of exposure by inhalation depends on the diameter of sulfuric acid droplets, the presence of other pollutants in the air, humidity and the depth of breaths. Acute exposure can cause respiratory tract irritation and, in more severe cases, death from respiratory failure and glottic spasm. As a result of chronic exposure, respiratory irritation, chronic bronchitis and damage to tooth enamel is observed. Chronic exposure to sulfuric acid mist, in combination with other agents, can cause repeated damage of airway epithelial cells and consequently lead to cancerous changes.
The Expert Group for Chemical Agents suggest maintaining the current values of MAC-TWA (1 mg/m³) and MAC-STEL (3 mg/m³) for mists of sulfuric acid(VI) and additionally suggest adopting MAC-TWA (OEL) of 0.05 mg/m³ for the thoracic fraction. This value is consistent with the value accepted by the Scientific Committee (SCOEL) in the European Union in Directive 2009/161/EC; this level of exposure is to protect workers from adverse effects of irritation. Notation “C” (corrosive) is considered appropriate.

Trichloroacetic acid. Documentation
 Agnieszka Jankowska, Karolina Bystry, Sławomir Czerczak

Trichloroacetic acid is used in the production of some herbicides, in medicine, research laboratories, as a solvent and as an intermediate product in organic and inorganic synthesis. Trichloroacetic acid is corrosive by direct skin or eye contact with concentrated aqueous solutions. The primary effect of this substance is local irritation. For trichloroacetic acid there is no reliable dose-response information for sensory irritation.
Therefore it was proposed to establish a MAC value for trichloroacetic acid by analogy to monoch-loroacetic acid. Although there is no dose-response data for the irritation effect of monochloroacetic acid, the MAC value was set at 2 mg/m³ and the STEL value at 4 mg/m³ on the basis of expert judgment. Considering evidence on corrosive properties of trichloroacetic acid, additional deter-mination with the “C” letter was proposed.

 Nitroethane. Documentation
Andrzej Sapota, Małgorzata Skrzypińska-Gawrysiak

Nitroethane is a colorless oily liquid with a mildly fruity odor. It is used mainly as a propellant (e.g., fuel for rockets), as well as a solvent or a dissolvent agent for cellulose esters, resins (vinyl and alkyd) and waxes, and also in chemical synthesis. Occupational exposure to nitroethane may occur in the processes of its production and processing. According to data provided by the Sanitary and Epidemiological Station in Bydgoszcz, Poland, as of 2007 there had been no cases in the Polish industryof workers’ exposure to this compound that would exceed the maximum admissible concentration (MAC) value of 30 mg/m³. Nitroethane can be absorbed into the body via inhalation of its vapors or by ingestion. The discussed cases of nitroethane acute poisoning applied to children under three years of age caused by an accidental ingestion of artificial fingernail remover containing pure nitroethane. A few hours after ingestion cyanosis and sporadic vomiting were observed in children and the methemoglobin level reached 40–50%. There are no data on chronic nitroethane poisoning in humans or data obtained from epidemiological studies. On the basis of the results of acute toxicity studies, nitroethane has been classified as a hazardous com-pounds. However, there has been no evidence of its eye and dermal irritation or allergic effects. The studies of sub-chronic (exposure lasting from 4 to 90 days) and chronic (2-year) exposure to nitroethane, carried out on rats and mice (concentration range, 310–12 400 mg/m³), revealed the methemoglobinogenic effect, as well as minor damage to the liver, spleen, salivary gland and nasal turbinates caused by nitroethane. Niroethane has shown neither mutagenic nor carconogenic effects. There has been no evidence of its influence on fertility either. After chronic (2-year) exposure of rats to nitroethane at 620 mg/m³ (the lowest observed adverse effect level – LOAEL), there was a slight change in the body mass of exposed animals, but there were no anomalies in hematological, biochemical and histopathological examinations. By applying the LOAEL value of 620 mg/m³ and relevant coefficients of uncertainty, the value of 75 mg/m³ has been suggested to be adoptedas the MAC value for this compound. There are no grounds for setting the value of short-term exposure limit (STEL) for nitroethane. On account of its methemoglobinogenic effect, 2% Met-Hb has been suggested to beadopted as the value of the biological exposure index (BEI), a value already adopted for all methemoglobinogenic substances.

 Hydrogenated terphenyls. Documentation
 Krystyna Sitarek

Hydrogenated terphenyls are a mixture of ortho-, meta- and para- isomers of terphenyl in various stages of hydrogenation. Hydrogenated terphenyls are clear, oily, pale-yellow liquids that dissolve slowly in acetone and weakly in ethanol. They are used as heat transfer fluids, solvents, lubricants, and as nuclear and hydraulic coolants. Acute oral LD50 values for 40% hydrogenated terphenyls for rats are 17500 mg/kg b.w. or 10200 mg/kg b.w., for mice - 12500 mg/kg b.w.; CL50 for rats – 11100 mg/m³. Hydrogenated terphenyls (40%) are hepatotoxic agents for rats. Repeated inhalation or dietary exposure induced an increase in liver weight and increasedthe activity of drug-metabolizing enzymes: ethoxycoumarinO-deetylase and aryl hydrocarbon hydroxylase in the liver.
Hydrogenated terphenyls (40%) are not mutagenic orgenotoxicor carcinogenic. At doses non-toxic for mothers they did not induce malformations in rats. Hydrogenated terphenyls (40%) did not much accumulate in the tissue of rats. Faeces are the primary elimination after oral administration; half-life is 14h.
The proposed occupational exposure limit TWA of 12.5mg/m³ for hydrogenated terphenylsis based on the LOAEL of 100 mg/m³. Hepatotoxic effects observed in rats exposed toTherminol 66 by inhalation were not toxic. Considering that hydrogenated terphenyls (40%) do not produce irritating effects , the Expert Group has not established a STEL value.

 Tributyltin compounds(IV). Documentation
 Andrzej Starek

Tributyltin compounds(IV), (TBT) are high boiling liquids used mainly as agricultural biocides, disinfectants, wood preservatives, stabilizers and antifouling agents, and also as supplements for textile materials, paints and paper. In humans acute poisoning by these chemicals through the respiratory tract are manifested in hepatic injury, hypoglycemia, glucosuria and respiratory system disorders similar to bronchial asthma. Chronic intoxication with TBT in humans has not been described. TBT are classified as toxic substances. Both single and repeated exposure to these chemicals, main-ly through the gastrointestinal tract, lead to hepatotoxic, nephrotoxic, neurotoxic, immunotoxic, and hematotoxic effects, and also to skin and mucous membrane irritation after local application. The recommended health-based maximum admissible concentration (MAC) for tributyltin compounds (IV) of 0.02 mg/m³ is based on the NOAEL value (0.16 mg/m2) derived from 4–5 weeksexperiment on rats, and relevant uncertainty factors. Inflammatory alterations in the respiratory tract and reduction in the number of lymphocytes in thymus, spleen and lymph nodes are the critical effects of these chemicals. No STEL and BEI values have been proposed. Moreover, “FT” (fetotoxic) and Sk (ab-sorption through the skin) notations are recommended.