Classification of dangerous goods for hydrogen sulfide

1. United Nations GHS classification standards

2. 

3. According to the Globally Harmonized System of Classification and Labeling of Chemicals (GHS), hydrogen sulfide (H₂S) falls into the following hazard categories:

4. 1. Physical hazards

5. • Flammable gases (Category 1)

6. Hydrogen sulfide can form an explosive mixture when mixed with air at 20°C and 101.3kPa standard pressure. The explosion limit is 4.3%~46% (volume ratio). It can easily burn and explode when exposed to open flames and high heat. Its combustion reaction equation is:

7. 2H2S+3O2----2SO2+2H2O (Elemental sulfur is generated when there is insufficient air: 2H2S+O2----2S+2H2O)

8. • Pressurized gas (compressed gas)

9. Hydrogen sulfide is usually stored in the form of compressed gas in cylinders with an internal pressure of ≥200kPa (gauge pressure). It may cause the container to explode when exposed to heat.

10. 2. Health hazards

11. • Acute toxicity - Inhalation (Category 2)

12. Hydrogen sulfide is a strong neurotoxicant. Inhalation of extremely high concentrations (>1000mg/m³) can cause respiratory and cardiac arrest within seconds, which is called "lightning death". Occupational exposure limits are as follows:

13. ◦ OSHA regulations: 8-hour weighted average 20ppm (28mg/m³), 10-minute peak 50ppm

14. ◦ NIOSH recommendation: 10-minute upper limit value 10ppm (14mg/m³)

15. 3. Environmental hazards

16. • Hazard to the aquatic environment - acute hazard (Category 1)

17. It is extremely toxic to aquatic life and can cause persistent pollution to water bodies and the atmosphere.

18. 2. China’s Classification Standards for Hazardous Chemicals

19. According to the "Catalogue of Hazardous Chemicals" (2015 Edition) and GB 13690-2009 "General Principles of Chemical Classification and Hazard Disclosure", hydrogen sulfide is classified as follows:

20. 1. Physical Hazard Classification

21. • Class 2.1 Flammable gases

22. Dangerous goods number: 21006, UN number: 1053, packing category: O52. Its physical properties are:

23. ◦ Colorless gas with a rotten egg smell (low concentration). At high concentration, the smell is lost due to paralysis of the olfactory nerve.

24. ◦ Relative density 1.19 (air=1), easy to gather in low-lying places

25. ◦ Autoignition temperature 260℃, minimum ignition energy 0.077mJ

26. • Metal corrosion (category 1)

27. Hydrogen sulfide aqueous solution is acidic (hydrosulfuric acid) and corrosive to most metals, especially copper, silver and other metals, which can form sulfide precipitation:

28. 2. Health hazard classification

29. • Acute toxicity (Category 1)

30. China's MAC (maximum allowable concentration) is 10mg/m³ (approximately 7ppm), which is a highly toxic gas. Symptoms of acute poisoning include:

31. ◦ Mild: stinging eyes, watery eyes, cough, headache

32. ◦ Moderate: confusion, pulmonary edema

33. ◦ Severe: lightning-type death, respiratory arrest

34. 3. Multiple hazards and label elements

35. 1. Main hazard labels

36. • Signal word: DANGER

37. • Hazard statements:

38. ◦ H220: extremely flammable gas

39. ◦ H280: Contains high-pressure gas; may explode when heated

40. ◦ H330: Fatal if inhaled

41. ◦ H400: Extremely toxic to aquatic life

42. 2. Secondary risks

43. Hydrogen sulfide has both skin corrosion/irritation (Category 1) and severe eye damage/eye irritation (Category 1) effects, and exposure to high concentrations can cause corneal ulcers and chemical burns to the skin.

44. 4. Safety protection measures

45. 1. Operational requirements

46. • Tightly enclosed, provide adequate ventilation, and use explosion-proof ventilation systems and equipment

47. • Keep away from fire and heat sources, and smoking is strictly prohibited in the workplace

48. • Equipped with hydrogen sulfide gas detector (lower detection limit ≤1ppm) and positive pressure air respirator

49. 2. Emergency treatment

50. • Leakage: Evacuate immediately to a windward location, isolate small leaks by 150m, large leaks by 300m, and dilute and dissolve with spray water

51. • Fire: Cut off the air source (if possible), use mist water, dry powder or anti-soluble foam to extinguish the fire. Do not use sand to cover the fire.

52. • First aid for poisoning: Move quickly to fresh air, keep the respiratory tract open, perform artificial respiration if necessary (no mouth-to-mouth), and seek medical attention immediately

53. 5. Legal basis

54. 1. United Nations GHS: ST/SG/AC.10/30/Rev.2 (2nd revised edition)

55. 2. Chinese standards:

56. ◦ GB 13690-2009 "General Principles for Classification and Hazard Disclosure of Chemicals"

57. ◦ GB 20577-2006 "Flammable Gases"

58. ◦ "Catalogue of Hazardous Chemicals" (2015 Edition) Serial No. 2828

59. 3. Transportation specifications:

60. ◦ UN number 1053, dangerous goods category 2.3 (toxic gases), secondary hazard 2.1 (flammable gases)

61. ◦ Packaging method: steel gas cylinder, frosted glass bottle and ordinary wooden box

62. (Note: Actual labels should include pictograms of flames, gas bottles, skull and crossbones, environmental hazards, etc.)