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Dangerous safety

Dangerous safety. Working safely..... An illusion?. Occasion . Course on “Risk Determination of Dangerous Substances” Final assignment was to write term paper Subject: Analyse real-life incident and come to conclusions and recommendations. Content of presentation. Description of case

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Dangerous safety

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  1. Dangerous safety Working safely..... An illusion?

  2. Occasion • Course on “Risk Determination of Dangerous Substances” • Final assignment was to write term paper • Subject: Analyse real-life incident and come to conclusions and recommendations Dangerous safety

  3. Content of presentation • Description of case • Handling of incident • Consequences of exposure in the human body • Types and functioning of respiratory protection • Comparison of hexane and phosphine • Conclusions • Recommendations Dangerous safety

  4. Description of case • Coaster loaded with cocoa • Pesticide encountered on the cargo • Removal of the pesticide • Measurement of atmosphere in the cargo hold • Weather conditions • Reaction of pesticide • Fire brigade called in • Transport of the pesticide • Relationship with activities of the Transport and Water Management Inspectorate Dangerous safety

  5. Objectives • Improve understanding of the effects of exposure • Expand understanding of how the available PPE functions • Give better understanding of the limits in the use of PPE • Give insight into the relationship of odour perception vs. LC50 value Dangerous safety

  6. Research questions • What physiological effects are caused by the substance phosphine in the body after exposure? • What personal protective equipment is available in order to prevent exposure to this substance? • What physical and/or chemical characteristics assure the effectiveness of respiratory protection? • What circumstances limit the use of environment-dependent respiratory protection? Dangerous safety

  7. Incident study • Control measures for preventing exposure • Removal of (the residues of) the pesticide • Investigation into the cause • Regulations • Dangerous substance • Characteristics • Transport to A.V.R. (Rijnmond Waste Processing Plant) Dangerous safety

  8. Chemical information • Aluminium phosphide pellets • AlP + 3 H2O -> Al(OH)3 + PH3 • LC50 mg/l/4h = PHOSPHINE 0.015. • Subsection ADR 2.2.61.1.7.3 applies • LC50 value (1 hour): 0.015 x 4 = 0.06 mg/l/1h • Table 2.2.61.1.7 of the ADR/VLG : highly toxic gas, PG I Dangerous safety

  9. Effects of exposure • External: • Irritation of the eyes and the skin • Internal: • The cellular respiration is obstructed; • Inhalation can cause pulmonary oedema within a few hours; • Impact on the liver, the central nervous system and the heart; • In serious cases, chance of coma and rapid death. Dangerous safety

  10. Anatomy of respiration 1 • Trachea (windpipe) • Main bronchi • Lobar bronchi (2 on the left - 3 on the right) • Segmental bronchi • Bronchioles • Terminal bronchioles with alveoli Dangerous safety

  11. Anatomy of the lungs Dangerous safety

  12. Anatomy of respiration 2 • Pulmonary function • Pulmonary vein - Pulmonary artery • Intake of oxygen – release of carbon dioxide • Diffusion Dangerous safety

  13. Diffusion Permeable membrane Permeable membrane Permeable membrane Dangerous safety

  14. Cellular respiration • Energy metabolism in our cells • Haemoglobin • Transport protein • Brings O2 into cells • Bohr effect • Increase in CO2 • Reduction in degree of acidity • Increase in temperature • Higher affinity binding haemoglobin • Higher affinity crowding out oxygen Dangerous safety

  15. Effect of phosphine on cellular respiration 3 Phases • Glycolysis • Glucose is converted into pyruvic acid • C6H12O6 ? 2 C3H4O3 • Citric acid cycle • Oxidative phosphorylation Dangerous safety

  16. Less energy in our cells. Target organs function less well Liver Purification of blood Less energy Reduced transport processes Accumulation of substances (fats) Even lower functioning of liver cells Hepatic steatosis Cirrhosis of the liver Heart Reduced pumping function Low blood pressure Tachycardia Cardiac arrhythmia Fatigue Cardiac steatosis Myocardial infarction Effects of disrupting oxidative phosphorylation Dangerous safety

  17. Odour threshold vs. limit value • Odour threshold: • Lowest concentration • Gaseous substance • Perceptible by individual with the nose • Perception of odour: • Stimulation threshold exceeded • Via fila olfactoria (olfactory sensors in the nasal mucosa) • Nervus Olfatorius (Olfactory nerve) • Stimulus reaches cerebral cortex • Perception + possible reaction Dangerous safety

  18. Determining odour threshold • Basis odour measurement • Perception by individual with the nose • No physical or chemical unit as basis • Olfactory method • Composition of representative panel • Offer odour air • Adapt concentration by olfactometer • Threshold value: 50 % yes – 50 % no. • Threshold value of phosphine: between 0.04 and 5 ppm • LC50 value of phosphine: 0.06 mg/litre • Conclusion: threshold value higher than LC50 value Dangerous safety

  19. Protective equipment • Occupational hygiene strategy • Respiratory protection • Dependent respiratory protection • Filter boxes • Independent respiratory protection • Breathing air Dangerous safety

  20. Filters • Dust mask • Inert substance • Half-face mask/ Full-face mask • Exchangeable filter Dangerous safety

  21. Activated carbon Three ways: • Steam • Steam and chemical substance • Impregnation Dangerous safety

  22. Functioning of a filter • Balanced purification • Adsorption • Van der Waals forces • Small pores • 1 gram = surface area of 500 m2 and 1500 m2 • Breakthrough • Type A filter • Absorption • Chemical reaction with coating • Van der Waals forces • Even smaller pores • Type B, E, K filters Dangerous safety

  23. Codes Combination of filters or special filters have different codes Dangerous safety

  24. Limiting factors • 1. Concentration of the contaminant • 2.Respiratory rate • 3.Ambient temperature • 4.Relative humidity • 5.Hygiene factors Dangerous safety

  25. Independent breathing air • Breathing air cylinder • Compressor • Trolley • Certified • Limitation • Movement • Useful service life • 6-litre cylinder of 300 bar = 30 minutes • Sight Dangerous safety

  26. Hexane Immediate consequences: Irritating to the eyes After swallowing, pneumonia develops Impact on the central nervous system, with chance of: - lowering of consciousness - loss of consciousness at high concentration Chronic effects: Dry or cracked skin Can also have an effect on peripheral nervous system, with as result : - rapid fatigue - depressed appetite - muscle weakness - difficulties walking - possible reduction in fertility Phosphine Immediate consequences Irritating to the eyes, skin and respiratory organs After inhalation, pulmonary oedema can develop Impact on: - liver - heart - central nervous system Exposure can cause death Chronic effects: (very small quantities) Anaemia Bronchitis Gastrointestinal disorders Through impact on central nervous system: - Visual disturbances - Speech disorders - Motor disorders Physical effects in a nutshell Dangerous safety

  27. Conclusions • Primary effect: purifies • External factors limit useful service life of filter • No guarantee from supplier • Odour threshold of phosphine above LC50 value • Perception of odour not a timely warning Dangerous safety

  28. Recommendations • Expand understanding of the effects of exposure • Expand understanding of the functioning of filter boxes • Expand understanding of limiting external factors • Draw up list of substances for which odour threshold above limit values Dangerous safety

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