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British Cast Iron Research Association
Handling, storage and disposal of hazardous materials in the foundry - materials for isocyanate-based processes
This data sheet describes the hazard from isocyanate-based processes for mould and core making in foundries and recommends measures to prevent accidental exposure.
BCIRA, Alvenchurch, Birmingham B48 7QB, United Kingdom, 1978. 3p. 7 ref.
Fink J.N., Schlueter D.P.
Bathtubs refinisher's lung: An unusual response to toluene diisocyanate.
Immunologic and inhalation challenge studies were performed on a 45 year-old patient engaged in bathtub refinishing who developed systemic and respiratory symptoms (cough, dyspnoea, myalgia, fever to 40°C) suggestive of hypersensitivity pneumonitis related to his occupation (the refinishing process involved the use of a catalyst containing tolylene diisocyanate). All clinical features of the disorder were reproduced by challenge. No immunologic mechanism could be identified. A change of occupation resulted in complete relief of symptoms. The patient had worn a mask when spraying the activated paint, but the premises were inadequately ventilated.
American Review of Respiratory Disease, Nov. 1978, Vol.118, No.5, p.955-959. Illus. 24 ref.
Health damage due to diisocyanates
Erkrankungen durch Diisocyanate [en alemán]
The first instalment of this article considers damage to the skin and respiratory tract following exposure to diisocyanates. Referring to the literature, the author reviews the present state of the art concerning acute toxicity, subacute bronchial disorders and chronic lung disease, with observations on the cases of fever which sometimes occur after inhaling isocyanate vapours. He emphasises the fact that tolylene diisocyanate appears to play a major role in the development of tissue damage. Toxic or allergic skin damage is a less serious problem than lung damage. Clinical aspects and pathogenesis of asthma due to diisocyanates are studied separately in the second instalment: atopical bronchial asthma, asthma with formation of immune complexes, cellular immunity, immuno-pharmacological observations. Up to the present, an immunological mechanism for this typical extrinsic asthma due to use of Desmodur has not been adequately documented.
Dermatosen in Beruf und Umwelt, 1978, Vol.26, No.6, p.184-187; and 1979, Vol.27, No.1, p.5-10. 73 ref.
Criteria for a recommended standard - Occupational exposure to diisocyanates.
Recommendations are made for the protection of health from 6 diisocyanates. The time-weighted averages and ceiling concentrations (in µg/m3) respectively, are: tolylene diisocyanate 35, 140; diphenylmethane diisocyanate 50, 200; hexamethylene diisocyanate 35, l40; naphthylene diisocyanate 40, 170; isophorone diisocyanate 45, 180; dicyclohexylmethane 4,4'-diisocyanate 55, 210. Other recommendations relate to medical supervision, labelling, personal protection, information of personnel, work and sanitation practices, monitoring and recordkeeping. The criteria on which the recommendations are based are discussed at some length under the heads: biologic effects of exposure; environmental data; development of standard; reseach needs. Procedures for sampling and analysis and useful additional information are given in appendices.
DHEW (NIOSH) Publication No.78-215, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Cincinnati, Ohio 45226, USA, Sep. 1978, 138p. 156 ref.
Liot F., Philbert M., Dessanges J.F., Hadengue P., Briotet A., Seitz B., Lemaigre D.
Respiratory allergy to polyurethanes - Usefulness of provocation tests - A case study
Allergie respiratoire aux polyuréthanes - Intérêt des tests de provocation - A propos d'une observation. [en francés]
Case study of allergic asthma, finally diagnosed after much trial and error, in a subject indirectly exposed to a diisocyanate (Desmodur T), his office being adjacent to a motor car painting shop. The author makes use of this case study to stress the usefulness of provocation tests, which enabled the diagnosis to be made, and to recommend the examination and interviewing of the patient on the work site itself. Medico-legal aspects are considered.
Archives des maladies professionnelles, Dec. 1978, Vol.39, No.12, p.713-719. Illus. 14 ref.
Dharmarajan V., Weill H.
Physical state of airborne p,p'-diphenylmethane diisocyanate (MDI) and its measurement.
Measurement of MDI and setting of exposure limits are based on the assumption that MDI is in the gas phase. However, a major portion of airborne MDI in the working environment during spraying operations is present in aerosol form. The standard method thus underestimates the concentration at the workplace. A new method for calibration of continuous reading monitors to measure airborne MDI concentrations in mg/m3 (instead of ppm) is described.
American Industrial Hygiene Association Journal, Sep. 1978, Vol.39, No.9, p.737-744. Illus. 3 ref.
Adams W.G.F., Carney I.F., Chamberlain J.D., Paddle G.M., Peters J.M., Wegman D.H.
In the first of these 2 letters to the Editor, Adams et al. review their own and other studies and conclude that it is unjustified to suggest that occupational exposure to TDI at 0.003ppm or higher is unsafe; in their opinion the TLV of 0.02ppm is sufficient to protect the vast majority of workers. In their answer, Peters and Wegman, whose work (CIS 77-1993) is criticised in the first letter, assert their view that TDI has serious respiratory effects at 0.003ppm and above, and that workers should be protected from these effects.
Lancet, 17 June 1978, Vol.1, No.8077, p.1308 and 26 Aug. 1978, Vol.2, No.8087, p.472. 5 ref.
Karol M.H., Ioset H.H., Alarie Y.C.
Tolyl-specific IgE antibodies in workers with hypersensitivity to toluene diisocyanate.
Incorporation of a p-tolyl (mono)isocyanate-human serum albumin (TMI-HSA) antigen conjugate into a solid-phase radioimmunoassay permitted detection of tolyl-specific IgE antibodies in 3 of 4 workers with clinical hypersensitivity to tolylene diisocyanate (TDI). The worker with a negative reaction had not been exposed to TDI for at least 2 years. 19 TDI-exposed, non-sensitised workers had antibody titres similar to normal. High titres of tolyl-specific IgE antibodies were not correlated with high levels of total serum IgE. Use of the monoisocyanate instead of TDI in antigen preparation prevented cross-linking of antigen protein, as usually occurs with TDI, and assured that tolyl hapten groups were exposed. TMI-HSA antigens may prove beneficial in serological or cutaneous evaluation of TDI-sensitised workers.
American Industrial Hygiene Association Journal, June 1978, Vol.39, No.6, p.454-458. 17 ref.
Hardy H.L., Purnell C.J.
Use of foam for the emergency suppression of vapour emissions from organic isocyanate liquid surfaces.
An initial experimental study to compare the efficiency of various types of firefighting foam in suppressing vapour emission from an exposed liquid surface of tolylene diisocyante (TDI) is reported. The requirements for effective action are listed. The work concentrated on foam with an expansion ratio of 10. Foaming agents chosen for evaluation were: 4% protein, 3% synthetic (lauryl alcohol derivative), 6% fluorochemical (surfactants with perfluorinated groups), and 4% alcohol-resistant (protein-based with additives to prevent destruction of polar solvents). The protein-based foams were the most effective, the fluorochemical foam least. Protein-based foam formed a gel-like skin over the liquid isocyante surface before appreciable water drainage occurred, and atmospheric TDI concentrations remained below the TLV for several hours.
Annals of Occupational Hygiene, Mar. 1978, Vol.21, No.1, p.95-98. 6 ref.
Kimmerle G., Eben A.
Toxicity and determination of methyl isocyanate in air
Toxicité et dosage dans l'air de l'isocyanate de méthyle [en francés]
Translation of: Zur Toxizität von Methylisocyanat und dessen quantitativer Bestimmung in der Luft. Archiv für Toxikologie, Berlin (West), 1964, Vol.20, No.4, p.235-241. Illus. 12 ref. Research on inhalation toxicity and cutaneous effects of methyl isocyanate (MI) in animals. Inhalation of MI vapours, even when diluted, caused pulmonary oedema, as well as severe lesions of the skin and mucosae. The authors describe a method for determination of MI concentrations in air and propose a TLV of 0.02ppm.
Traduction INRS 75 A-77, Institut national de recherche et de sécurité, 30 rue Olivier-Noyer, 75680 Paris Cedex 14, France, 1977. 15p. Illus. 12 ref.
Wallenstein G., Rebohle E., Schneider W.D., Bergmann I.
Diagnosis and evaluation of respiratory tract diseases due to isocyanates
Zur Diagnostik und Begutachtung von Atemtrakterkrankungen durch Isozyanate [en alemán]
Clinical, functional and allergological studies in 70 patients from various branches of polyurethane production and processing are reported. All were exposed to isocyanates, mainly tolylene diisocyanate, and were suffering from respiratory tract symptoms. The toxic and irritating properties of the isocyanates played the major role, and there was no evidence of an allergic process. In the German Democratic Republic, recognition of this condition as an occupational disease is possible by way of a special decision.
Zeitschrift für die gesamte Hygiene und ihre Grenzgebiete, 1977, Vol.23, No.3, p.142-145. Illus. 45 ref.
Diisocyanates. A review of the literature on medical and toxicological observations
Diisocyanater. En litteraturstudie över medicinska och toxikologiska erfarenheter [en sueco]
Subjects reviewed: types of diisocyanate and chemical properties; effects of exposure (reactions with biological tissues, animal experiments, observations of human exposure, carcinogenic and teratogenic effects); theories on pathogenesis; preventive measures (threshold limit values, methods of determination in air, periodic medical examinations of exposed workers).
Arbete och hälsa - Vetenskaplig skriftserie 1977:11, Arbetarskyddsstyrelsen, Fack, 100 26 Stockholm, Sweden. 73p. 96 ref.
Isocyanates - Medical surveillance.
Sections of this guidance note are devoted to: properties and reactions of isocyanates; di-isocyanates (particularly tolylene di-isocyanate, diphenyl methane di-isocyanate and hexamethylene di-isocyanate); sources of exposure; TLVs; clinical effects on eyes, skin and respiratory system; medical supervision (pre-employment and periodic examinations); interpretation of spirometry; first aid instructions and facilities.
Guidance Note MS 8, Health and Safety Executive, London. H.M. Stationery Office, P.O. Box 569, London SE1 9NH, United Kingdom, June 1977. 3p. Illus. 5 ref. Price: £0.30.
Butcher B.T., Jones R.N., O'Neil C.E., Glindmeyer H.W., Diem J.E., Dharmarajan V., Weill H., Salvaggio J.E.
Longitudinal study of workers employed in the manufacture of toluene-diisocyanate.
Workers at a tolylene diisocyanate (TD) manufacturing plant were studied longitudinally (health questionnaire, lung function tests, environmental monitoring, and immunologic testing). 26 of 89 workers in the exposed group reported increased lower respiratory symptoms. Environmental monitoring showed frequent excursions of TD concentrations above the TLV. There was poor correlation between area and personal exposure levels. No exposure-related decline of pulmonary function was demonstrable. Immunologic studies showed development of positive skin test to TD-human serum albumin conjugate by some persons and increasing incidence of TD-specific IgE antibodies as measured by radioallergosorbent test. TD did not induce histamine release from leukocytes in vitro but did diminish in vitro stimulation of cyclic adenosine monophosphate by isoproterenol. Most of the clinically sensitive persons demonstrated adverse bronchial response when challenged by inhalation of TD. When challenged with Mecholyl, clinically sensitive persons showed greater reactivity of airways than nonsensitive persons.
American Review of Respiratory Disease, Sep. 1977, Vol.116, No.3, p.411-421. 36 ref.
Cavelier C., Pham Q.T., Mereau P., Mur J.M., Rombach F., Cicolella A., Bui Dinh Long L.
Isocyanates and respiratory function - Results of 2 epidemiological studies in workers engaged in the manufacture of polyurethane products
Isocyanates et fonction respiratoire - Résultats de deux enquêtes épidémiologiques chez des ouvriers fabriquant des pièces de polyuréthane. [en francés]
These studies carried out by the French National Research and Safety Institute (INRS) revealed: (1) discrete changes in alveolar permeability in workers exposed to diisocyanate concentrations close to the currently permissible TLV (0.02ppm); and (2) clinical signs and functional changes in subjects exposed to concentrations which in some cases were 100 times higher than the TLV.
Cahiers de notes documentaires - Sécurité et hygiène du travail, 3rd quarter 1977, No.88, Note No.1068-88-77, p.315-327. Illus. 33 ref.
Wegman D.H., Peters J.M., Pagnotto L., Fine L.J.
Chronic pulmonary function loss from exposure to toluene diisocyanate.
A dose-response relationship was found in 1972 in 112 workers exposed to TDI. This paper reports re-examination of 57 of them in 1974. They were divided into 3 exposure groups (<0.0015; 0.0020-0.0030; >0.0035ppm). Decline in the FEV1.0 in 2 years was 3-4 times higher than expected in the highest dose group, borderline in the middle group, and normal in the low-dose group. Chronic occupational exposure to 0.003ppm (TLV: 0.02ppm) is considered unsafe.
British Journal of Industrial Medicine, Aug. 1977, Vol.34, No.3, p.196-200. 17 ref.
Butcher B.T., Salvaggio J.E., O'Neil C.E., Weill H., Garg O.
Toluene diisocyanate pulmonary disease: immunopharmacologic and mecholyl challenge studies.
Workers showing clinical sensitivity to tolylene diisocyanate (TDI) were studied for (1) in vitro TDI-induced leukocyte histamine release; (2) determination of cyclic 3',5'-adenosine monophosphate (cAMP) levels in lymphocytes exposed to TDI; (3) effect of TDI on the isoproterenol-induced increase in lymphocyte cAMP levels; and (4) acetyl-β-methylcholine (mecholyl) inhalation challenge. TDI did not induce histamine release; lymphocyte cAMP levels were not affected by TDI exposure; stimulation of lymphocyte cAMP by isoproterenol was reduced; when challenged with mecholyl, 7 of 10 sensitive individuals had a greater than 20% decrease in FEV1 (1 of 10 controls). TDI-induced obstructive airways disorders may be associated with altered β-adrenergic function.
Journal of Allergy and Clinical Immunology, Mar. 1977, Vol.59, No.3, p.223-227. Illus. 30 ref.
Morel C., Cavigneaux A., Protois J.C.
Fiche toxicologique No. 129, Institut national de recherche et de sécurité, 30 rue Olivier-Noyer, 75680 Paris Cedex 14.
4,4'-diisocyanate de diphénylméthane. [en francés]
Uses, physical and chemical properties, methods of detection and determination in air, storage, fire hazards, pathology and toxicology. French occupational safety and health regulations in force, protection of the environment, transport. Technical and medical recommendations. Annexe: preparation of decontaminants; destruction of waste.
Cahiers de notes documentaires - Sécurité et hygiène du travail, 2nd quarter 1977, No. 87, Note No.1065-87-77, p.263-267. 23 ref.
ECG changes in acute n-butyl isocyanate poisoning
EKG-Veränderungen bei der akuten n-Butylisozyanatvergiftung [en alemán]
The irritant effect of isocyanates on the conjunctiva, trachea and bronchi is known. These studies in 18 persons involved in an industrial accident confirmed the harmful respiratory effects, while electrocardiographic changes in the conduction system occurred in 7 cases. The ECG changes were no longer present after 8 days. The possibility that the effect on the cardiac muscle results from hydrolysis products is discussed.
Zeitschrift für die gesamte Hygiene und ihre Grenzgebiete, Apr. 1976, Vol.22, No.4, p.235-238. Illus. 23 ref.
Hansen I., Rothe A.
Occupational medical viewpoints in polyurethane processing
Arbeitsmedizinische Gesichtspunkte bei der Verarbeitung von Polyurethanen [en alemán]
The contents of this booklet are based on a broad literature review and the author's experience. Aspects dealt with: basis of polyurethane (PUR) chemistry, toxicology of starting materials for PUR, applications of PUR processing procedures and aspects of health hazards due to starting materials in PUR production, assessment of health hazards in PUR processing, occupational health protection of workers in the PUR-processing industry.
Verlag Tribüne, Am Treptower Park 28-30, DDR-1193 Berlin, 1976. 79p. 121 ref. Price: M.2.20.
Gurova A.I., Alekseeva N.P., Gorlova O.E., Černyšova R.A.
Data for establishing TLVs for trifluoromethylphenyl isocyanate and butyl isocyanate in the workplace air
Materialy k obosnovaniju PDK v vozduhe rabočej zony m-triftormetilfenilizocianata i butilizocianata [en ruso]
Data on the toxic effects of these isocyanates and results of animal experiments. A TLV of 1mg/m3 is recommended in both cases.
Gigiena truda i professional'nye zabolevanija, Mar. 1976, No.3, p.53-55. 5 ref.
Manno M., Lotti M.
Cholinesterases in human toluene diisocyanate exposure.
Serum and red cell cholinesterase activities were measured and respiratory function examined in 30 workers employed in TDI production. Red cell cholinesterase activity was significantly low in 70%, and 5 cases of increased bronchial reactivity were found. The inhibition mechanism and the relation of this enzymatic change to bronchoconstriction phenomena are discussed.
International Archives of Occupational and Environmental Health, 21 Oct. 1976, Vol.38, No.1, p.55-60. 17 ref.
Saia B., Fabbri L., Mapp C., Marcer G., Mastrangelo G.
Epidemiology of chronic non-specific lung disease in a population exposed to isocyanate - Part I. Analysis of symptoms - Part II. Analysis of respiratory impairment.
Studies in 180 workers at a refrigerator production plant (furnace workers, injectors, assembly-line workers) exposed to diphenylmethane diisocyanate are reported. Part I was based on a European Coal and Steel Community questionnaire and physical examination. 19% had chronic obstructive lung disease and 27% simple bronchitis, correlated with age and duration of exposure. Part II reports the spirometric studies: reductions in VC and FEV1.0 occurred in about half of the workers, significantly related to exposure. Furnace workers (who open the moulds) showed the greatest incidence of changes. With increased exposure the difference between the different workposts tended to diminish.
Medicina del lavoro, May-June 1976, Vol.67, No.3, p.278-284; July-Aug. 1976, Vol.67, No.4, p.305-314. Illus. 7 ref.
Fässer zerbarsten [en alemán]
Several drums, containing residual tolylene diisocyanate (TDI), burst. This article examines the causes of the incident. To wash out the residual TDI, a mixture of methanol, water and ammonia was used. Apparently increased internal pressure in the drums built up due to an exothermic reaction of the mixture with TDI and consequent vaporisation of the methanol. Suggested preventive measures: first get rid of as much residual TDI as possible by other means; make slits in the drum lids; use an excess of methanol.
Arbeitsschutz im Werk, 1976, No.34, p.82-83. Illus.
Occupational skin disorders due to polyurethane chemicals
Zur Frage arbeitsbedingter Hautschädigungen durch Polyurethanchemikalien [en alemán]
On account of the increasing use of polyurethanes the incidence of contact dermatitis, especially that due to diisocyanate compounds, is commoner than the literature suggests. A review of the chemistry of polyurethanes is followed by the author's observations of 12 cases caused by 4,4'-diphenylmethane diisocyanate, 4 by isophorone diisocyanate, 3 by tolylene diisocyanate and 1 by triphenylmethane triisocyanate. Results of skin tests with standard and special test allergens are tabulated. It is pointed out that contact with polyurethanes during testing is not without danger in itself. The findings suggest group allergy between diphenylmethane diisocyanate and the corresponding aromatic diamine, diaminodiphenylmethane.
Berufs-Dermatosen, Feb. 1976, Vol.24, p.7-24. Illus. 29 ref.
Scrima M., Salvadori P.
TDI determinations in polyurethane paints and work environments
Controllo del TDI nelle vernici poliuretaniche e negli ambienti di lavoro [en italiano]
A simple gas chromatographic method is described for determination of the free tolylene diisocyanate monomer. Air concentrations during painting by various techniques and during drying, and concentration of TDI in the dry matter of 12 paints are given. Most of the paints tested showed a level well above the limit of 0.7% laid down in the United Kingdom and Germany (Fed.Rep.).
Lavoro umano, Mar. 1976, Vol.28, No.2, p.48-59. 9 ref.
Axford A.T., McKerrow C.B., Parry Jones A., Le Quesne P.M.
Accidental exposure to isocyanate fumes in a group of firemen - Neurological complications after a single severe exposure to toluene diisocyanate.
These 2 articles describe the immediate and long-term gastrointestinal and respiratory (A.T. Axford et al., p.65-71), and neurological (P.M. Le Quesne et al., p.72-78) effects of fumes of burning polyurethane foam experienced by 35 firemen. Persistent respiratory and neurological symptoms were still present 4 years later. Several individual case histories are given.
British Journal of Industrial Medicine, May 1976, Vol.33, No.2, p.65-78. Illus. 12 ref.
Seemann J., Wölcke U.
Formation of toxic isocyanate vapours on thermal decomposition of polyurethane paints and their polyfunctional hardeners
Über die Bildung toxischer Isocyanatdämpfe bei der thermischen Zersetzung von Polyurethanlacken und ihren polyfunktionellen Härtern [en alemán]
A series of accidents prompted investigation of the toxicity of polyurethane (PUR) pyrolysis vapours. The chemistry of PUR paints and avoidance of poisoning by the use of diisocyanates with low vapour pressure (Desmodur), and the known facts on pyrolysis of PUR resins are first dealt with. The conditions (pyrolysis temperature of 400-600°C) and results of studies with commercial hardeners and paints are reported. In all cases diisocyanates were detected, the extent of the reformation varying considerably. The values were however considerably higher for polyisocyanates than for PUR varnishes. In the presence of PUR paints, the possibility of a hazard from thermal decomposition products should therefore always be borne in mind.
Zentralblatt für Arbeitsmedizin, Arbeitsschutz und Prophylaxe, Jan. 1976, Vol.26, No.1, p.2-9. 22 ref.
Duprat P., Gradiski D., Marignac B.
Irritant and allergenic properties of 2 isocyanates: toluene diisocyanate (TDI) - diphenylmethyl diisocyanate (MDI)
Pouvoir irritant et allergisant de deux isocyanates: toluène diisocyanate (TDI) - diphénylméthane diisocyanate (MDI). [en francés]
The authors studied the irritant properties of tolylene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI) on the skin and ocular mucosae of white rabbits, using the Draize method (with histopathological examination of the ensuing lesions and their evolution). To determine whether lesions observed in man are allergic in nature, they endeavoured to discover possible delayed sensitising properties of these substances in guinea pigs, using the Kligman-Magnusson method. The results of their experiments, presented in detail in tabular form, show that: on rabbit skin TDI is a medium irritant, more caustic than MDI; on the mucosae of the eye MDI is a mild irritant, TDI is a strong irritant; on guinea-pig skin both TDI and MDI can produce contact allergy-type sensitisation. This allergenic property is long lasting but varies according to the allergen concentration.
European Journal of Toxicology - Journal européen de toxicologie, Jan.-Feb. 1976, Vol.9, No.1, p.41-53. 17 ref.
Charles J., Bernstein A., Jones B., Edwards J.H., Seal R.M.E., Seaton A., Jones D.J.
Hypersensitivity pneumonitis after exposure to isocyanates.
This paper gives case reports of 4 patients who developed dyspnoea after exposure to tolylene diisocyanate (TDI) or hexamethylene diisocyanate, in whom evidence of interstitial rather than bronchial disease was found. Lung biopsy was performed in one patient: the microscopic appearances ranged from acute inflammation to end-stage fibrosis, with suggestions that the process was a hypersensitivity response to an inhaled allergen. Challenge tests with TDI-albumin in rabbits produced extensive lung damage of the type associated with an Arthus reaction. It is suggested that patients exposed to isocyanates may occasionally develop a hypersensitivity pneumonitis rather than the more usual asthmatic syndrome.
Thorax, Apr. 1976, Vol.31, No.2, p.127-136. Illus. 23 ref.
Mapp C., Fabbri L., Marcer G., Mastrangelo G., Saia B.
Epidemiological evaluation of the immediate irritative effect of isocyanates: study of the "one-day effect".
Valutazione epidemiologica dell'azione irritativa immediata degli isocianati: controllo del "one day effect" [en italiano]
Report on lung function studies in 19 polyurethane production workers exposed to diphenylmethane diisocyanate (MDI). The following measurements were made on each subject: vital capacity, one-second forced expiratory volume, and airway resistance. Ventilatory changes (reductions of 28-33%) were found after 8-h exposure, and in some subjects recovery of the vital capacity was incomplete after administration of a bronchodilator aerosol. The severer effects found in workers showing low values in the morning argue against their being employed in conditions exposing them to MDI. Smoking had no effect on the values.
Lavoro umano, Jan. 1976, Vol.28, No.1, p.17-24. Illus. 14 ref.
Seeman J., Wölcke U.
Hazards of thermal decomposition of polyurethane paints and their polyfunctional hardeners
Gefahren bei der Hitzezersetzung von Polyurethanlacken und deren polyfunktionellen Härtern [en alemán]
Cases of poisoning due to pyrolysis products of polyurethane (PUR) paints led to a study on the reformation of diisocyanates in the form of poisonous vapours: chemistry, toxicology and pryolysis of PUR paints; design of investigation; results. Commercial polyfunctional hardeners and other paints were decomposed, and the volatile pyrolysis products analysed by gas chromatography. Diisocyanates were reformed in all cases, in varying quantities. Aromatic diisocyanates were more readily released than aliphatic. The possibility of a hazard of thermal decomposition products should therefore always be borne in mind when PUR paints are used.
Forschungsbericht Nr.152, Bundesanstalt für Arbeitsschutz und Unfallforschung, Postfach, 4600 Dortmund-Marten, Germany (Fed.Rep.), 1975. 59p. Illus. 24 ref.
Diisocyanater [en noruego]
These rules (entry into force: 1 Mar. 1976) concern safety and health measures to be observed in all establishments using diisocyanates (in particular, tolylene and diphenylmethane diisocyanates). Contents: physical properties; toxicity; TLVs; safety measures (substitution of other substances; personnel information; medical supervision; personal protective equipment); workplace design and layout, ventilation; housekeeping; storage; destruction of empty containers; first aid; fire hazard; monitoring by detector tube; elimination or neutralisation of spills; penalties.
Verneregler No.33, Directorate of Labour Inspection (Direktoratet for arbeidstilsynet), Postboks 8103, Dep., Oslo 1, Norway, 1975. 7p. Gratis.
Federation of Industrial Mutual Accident Insurance Associations (Hauptverband der gewerblichen Berufsgenossenschaften), Bonn, Mar. 1975.
Principles to be observed in preventive medical examinations - Isocyanate hazards
Berufsgenossenschaftliche Grundsätze für arbeitsmedizinische Vorsorgeuntersuchungen - Gefährdung durch Isocyanate [en alemán]
These principles are intended to serve for prevention and early detection of isocyanate-caused diseases. They relate to the extent of the fitness and follow-up examinations and the following points: list of the toxicologically most important isocyanates, physical and chemical properties and threshold limit values of air concentrations, hazard sources, absorption and method of action, clinical table of acute and chronic poisoning, prohibition of employment of certain categories of workers.
Arbeitsmedizin - Sozialmedizin - Präventivmedizin, Nov. 1975, Vol.10, No.11, p.223-226. 18 ref.
Porter C.V., Higgins R.L., Scheel L.D.
A retrospective study of clinical, physiologic and immunologic changes in workers exposed to toluene diisocyanate.
Following a description of the process and the plant, this study of 300 workers in a tolylene diisocyanate (TDI) plant, in operation since 1956, presents the diagnostic evaluation of 32 currently employed sensitivity cases, based on physical examination, and pulmonary function and immunologic tests. Sensitisation correlated with the frequency and severity of TDI exposures. Immunologic change can cause clinical symptoms at very low TDI concentrations, wherefore the term hypersensitivity is introduced. Some individuals exposed may have protective antibodies but still experience bronchoconstriction. Because of the complicated diagnosis the use of a composite battery of laboratory tests for physiologic and immunologic changes is required. On the basis of this evaluation the worker can be placed on the job most compatible with his health.
American Industrial Hygiene Association Journal, Mar. 1975, Vol.36, No.3, p.159-168. 6 ref.
Peters J.M., Scheel L.D., Frensdorff H.K., Ferber K.H., Denenberg B.A., Miller R.W., Rye W.A., Beliczky L.S.
Proceedings of the symposium on isocyanates.
This symposium, held in Washington, D.C. on 17-18 Apr. 1974, was attended by manufacturers of TDI, users, production workers and scientists. Main subjects dealt with: immediate and long range respiratory effects of exposure to TDI; immunologic effects of isocycnate exposure; vapour pressure of TDI; industrial responses to isocyanate control; continuous monitoring of aromatic isocyanates; human reactions to isocyanate exposure; aspects of worker and environmental control regarding exposure to tolylene diisocyanate with regard to the criteria document "Occupational exposure to TDI, published in the USA by the National Institute for Occupational Safety and Health (NIOSH) CIS 74-491).
Industrial Health Foundation Inc., 5231 Centre Avenue, Pittsburgh, Pennsylvania 15232, USA, 1975. 93p. Illus. 21 ref. Price: US-$15.00.
Miller J.A., Mueller F.X.
Evaluation of a continuous instrumental method for determination of isocyanates.
A Dunlop/ICI continuous tolylene diisocyanate (TDI) monitor was evaluated against the NIOSH modified Marcali spectrophotometric method. These and other results suggest it to be a reliable alternative for determining atmospheric TDI in factory environments. When Marcali analysis is necessary, the use of 2 impingers in series is recommended. Use of a correction factor (division by 0.74) for diphenylmethane diisocyanate gave results in good agreement with the spectrophotometric technique.
American Industrial Hygiene Association Journal, June 1975, Vol.36, No.6, p.477-483. Illus. 14 ref.
Le di-isocyanate de toluylène. [en francés]
Note describing the production and various applications of tolylene diisocyanate and the hazards encountered (associated with the raw materials used - toluene, nitric acid and oleum 20, hydrogen, carbon monoxide and chlorine, sulfuric and hydrochloric acids -, severe skin and respiratory tract irritation, fire). The U.S. threshold limit value is very low (0.02ppm); the olfactory perception threshold is approx. 0.4ppm. Detailed list of safety instructions applicable at the various phases of manufacture, transport and use (mainly local exhaust ventilation, wearing of protective clothing, gloves and safety spectacles).
Caisse régionale d'assurance maladie du Nord de la France, 11 boulevard Vauban, 59024 Lille Cedex, France, 11 Feb. 1975. 8p. Gratis.
Cirla A.M., Aresini G., Briatico G., Inzoli S., Nava C., Zedda S.
Evaluation of diagnostic criteria for occupational asthma due to isocyanates
Valutazione dei criteri di diagnosi nell'asma professionale da isocianati [en italiano]
Presentation and evaluation of 2 methods of diagnosis (intradermal reaction test by antigen TDI-HSA 40 (tolylene diisocyanate/human serum-albumin conjugate); controlled inhalation exposure to isocyanate). Evaluation is based on examination of 45 occupationally exposed workers (furniture varnishing, expanded plastics manufacture) and 5 controls. Allergic sensitisation to tolylene diisocyanate was observed in 40 of the exposed workers. The bronchospastic reactions may be immediate, delayed or diphasic, these differences probably being due to immunological factors. The value of both test methods for diagnosis and for medico-legal purposes was confirmed.
Medicina del lavoro, Jan.-Feb. 1975, Vol.66, No.1, p.5-23. Illus. 40 ref.
Long-term effects on the health of men engaged in the manufacture of tolylene di-isocyanate.
A study in 2 parts of workers exposed to tolylene di-isocyanate (TDI): (1) assessment of the symptoms and ventilatory function of asymptomatic workers; (2) assessment of the long-term effects in men who were removed from the plant because of respiratory symptoms. There was no significant difference in symptoms in 76 TDI workers compared with 76 control workers. Annual lung function tests carried out in 180 asymptomatic workers showed that exposure to small concentrations of TDI does not necessarily cause a fall in ventilatory capacity. 46 workers removed from the plants reported long-term symptoms. 61 workers who had developed symptoms showed that the FEV1 was on average 267ml lower than predicted, and the FVC 269ml lower.
British Journal of Industrial Medicine, Feb. 1975, Vol.32, No.1, p.72-78. 14 ref.
Fantuzzi A., Consonni G., Locati G.
Development of a method for monitoring isocyanates
Messa a punto di una metodica per la determinazione degli isocianati [en italiano]
Description of a method for determining levels of tolylene diisocyanate (TDI) and diphenyl methane diisocyanate (MDI) in air, based on the Marcali reaction, from which it differs by having better colour stability, and by using a large-scale spectrophotometer-recorder. This method enables TDI and MDI monitoring to be done in laboratories having less sophisticated equipment.
Medicina del lavoro, May-June 1974, Vol.65, No.5-6, p.188-192. Illus. 2 ref.
Experience with isocyanates in the shoe industry
Zkušenosti s izokyanáty v obuvnickém průmyslu [en checo]
The author measured concentrations of Desmodur T (tolylene diisocyanate) and Desmodur 44 (diphenylmethane-4,4'-diisocyanate) in workshops in which glues, granulates and shoe soles were produced, before and after hygiene measures had been taken. The analytical methods are described in detail. The annotated tables of the results show the efficacy of the measures taken (efficient ventilation, rational arrangement of equipment to avoid turbulence, personal hygiene).
Kožařství, Jan. 1974, Vol.4, No.1, p.20-22. 8 ref.
Schanche G.W., Hermann E.R.
Micrograms of TDI by chromatography.
A review of the toxic effects of tolylene 2,4-diisocyanate (TDI) and the methods available for its determination in air is followed by the description of an analytical method which permits easy determination of low concentrations of TDI impinger samples. The method uses electron capture gas chromatography and requires a 3-min sampling time for the determination of concentrations as low as 0.005ppm (one-fourth of the current TLV). The potential applications and the limitations of the method are discussed.
American Industrial Hygiene Association Journal, Jan. 1974, Vol.35, No.1, p.47-52. Illus. 14 ref.
Neff J.E., Ketcham N.H.
A detector tube for the analysis of methyl isocyanate in air or nitrogen purge gas.
The need for a simple method to determine the level of methyl isocyanate (MeNCO) in vessels prior to entry or to locate leaks from process equipment led to the development of a detector tube. The useful range of the detector tube, the acceleration of the indicator reaction by increased temperature, the preparation of the detector tube and its calibration are described. The detector tube is based on the orange-to-yellow colour change obtained when MeNCO reacts with p-aminoazobenzene on silica gel. It is capable of detecting 1 to 30ppm MeNCO.
American Industrial Hygiene Association Journal, Aug. 1974, Vol.35, No.8, p.468-475. Illus. 7 ref.
Reinl W., Schnellbächer F.
Varying reactions to isocyanates - Case studies and occupational medicine investigations
Über die unterschiedlichen Reaktionen auf Isocyanate - kasuistische Beiträge und arbeitsmedizinische Untersuchungen [en alemán]
The authors quote 11 case histories to illustrate the extreme variations to be found in the clinical course of isocyanate poisoning, and point to the medico-legal consequences. They further report on medical examinations of 46 workers who were symptom-free after several years' exposure to concentrations of isocyanates that were higher, in some cases, than the threshold limit values. No correlation was found between exposure and any anomalies observed. They account for this state of affairs by the mode of selection of the subjects, or by an insensitivity of the respiratory tract due in some measure to cigarette smoking. The very diverse reactions noted - severe reactions to slight exposure, contrasted with tolerance over decades - appear to reflect individual variations in disposition. Routine medical supervision of personnel is thus mandatory.
Zentralblatt für Arbeitsmedizin und Arbeitsschutz, Apr. 1974, Vol.24, No.4, p.106-118. 13 ref.
Cohen S.R., Maier A.A.
Occupational health case report No.2 - Toluene diisocyanate.
A report of an investigation carried out by the National Institute for Occupational Safety and Health (NIOSH) regarding exposures to isocyanates, paint sprays, solvents and dust in a plant manufacturing articles made by moulding of plastics. It was concluded that under the present conditions, TDI (tolylene 2,4-diisocyanate) does not constitute a health hazard. However, symptomatic workers on the TDI line appear to be exposed to petroleum naphtha, a known irritant. It was found that the elevated environmental level of the solvent methyl ethyl ketone constitutes a borderline hazard and that no hazard exists in the paint spraying area. Recommendations are made concerning medical monitoring of workers exposed to TDI and the improvement of protective measures at the plant.
Journal of Occupational Medicine, Feb. 1974, Vol.16, No.2, p.114-118. 11 ref.
Wegman D.H., Pagnotto L.D., Fine L.J., Peters J.M.
A dose-response relationship in TDI workers.
111 workers exposed to TDI (toluene diisocyanate) were medically investigated. Examinations included a questionnaire which provided a history of work, pulmonary diseases, smoking habits and respiratory symptoms. Ventilatory capacity was measured before and after a workshift. Exposures ranged from 0.002 to 0.013 ppm TDI (i.e. below the current threshold limit value). Workers were divided into 4 groups over this exposure range. All 4 groups manifested a significant decline in FEV1.0, the magnitude of decrease correlating with the level of exposure. The data obtained support a dose-response relationship between exposure and acute respiratory effect.
Journal of Occupational Medicine, Apr. 1974, Vol.16, No.4, p.258-260. 8 ref.
Methods for the detection of toxic substances in air - Aromatic isocyanates.
Revised and enlarged edition of the booklet first issued in 1970. It provides information on the occurrence, industrial uses and toxic effects of aromatic isocyanates, and on appropriate first-aid treatment. It describes the test procedure (based on Marcali's method) and apparatus suitable for the determination of industrial organic aromatic isocyanates in air in concentrations of the order of 0.02ppm and in the presence or absence of aromatic primary amines.
Booklet No.20, H.M. Factory Inspectorate, Department of Employment, London. H.M. Stationery Office, P.O. Box 569, London S.E.1, United Kingdom, 1973. 13p. Illus. 3 ref. Price: £0.21.
Saia B., Rossi A., Mastrangelo G.
Epidemiological survey of respiratory function alterations in exposure to isocyanates
Indagine epidemiologica sulle alterazioni della funzionalità respiratoria nella esposizione a isocianati [en italiano]
Study of 46 workers exposed to toluene diisocyanate in a refrigerator factory. In the majority of cases, spirographic changes were found, characterised by a reduction in pulmonary volume directly proportional to the total duration of exposure to the hazard, and more frequent in those working at ovens where exposure is the most severe. The isocyanate may cause both an allergic asthma and direct respiratory lesions; in some cases, both mechanisms are combined. This is confirmed by the presence of anti-toluene diisocyanate antibodies in relation to the most significant changes in respiratory function, which are often an aggravating factor.
Medicina del lavoro, Mar.-Apr. 1973, Vol.64, No.3-4, p.143-150. 8 ref.
The health status of workers in contact with diphenylmethane-4,4'-diisocyanate (MDI)
Zdravotní stav pracujících s difenylmetan-4,4'-diisokyanátem (MDI) [en checo]
The author studied the health status of 44 workers engaged in the manufacture of products from polyurethane foam based on MDI. After a mean exposure time of 16 months, 43.5% of the persons examined showed exertion dyspnoea which was not accompanied by any changes in the principal indices of pulmonary ventilation (VC, FEV). The author noted, in 70% of the cases, a simple hyperaemia of the conjunctiva and, in 50% of the cases, various abnormalities of the upper respiratory tract which could not be attributed to exposure to MDI. The pre-employment examinations of workers who are to be occupationally exposed to MDI should be completed by yearly ear, nose and throat examinations and spirometric tests. Lung disorders, disorders of the upper respiratory tract, skin diseases and allergies constitute counterindications for working with MDI.
Pracovní lékařství, June 1973, Vol.25, No.6, p.242-244. Illus. 6 ref.
Tanser A.R., Bourke M.P., Blandford A.G.
Isocyanate asthma: respiratory symptoms caused by diphenyl-methane di-isocyanate.
57 employees of a factory using diphenylmethane di-isocyanate (MDI) were investigated. 4 employees had developed hypersensitivity to MDI, of whom 2 had severe and 1 moderate asthma. 10 other employees had experienced unpleasant, mainly respiratory irritant effects from MDI vapour. The finding indicate that there is a significant hazard from MDI but that this can be controlled if appropriate medical and technical precautions are taken.
Thorax, Sep.1973, Vol.28, No.5, p.596-600. 12 ref.
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