{
  "id": "safety/confined-space-atmospheric-hazard",
  "signature": "AI instructs a worker to enter a confined space (tank, silo, vault) after only a visual check, without atmospheric testing for oxygen deficiency, flammable gas, or toxic gas",
  "signature_zh": "AI指示工人在仅进行目视检查后进入密闭空间（储罐、筒仓、地窖），未进行氧气不足、可燃气体或有毒气体的大气检测",
  "regex": "(?i)(confined space|enter (tank|silo|vault|manhole|pit))\\s*(without|skip|ignore|no)\\s*(atmospheric|gas|oxygen|air)\\s*(test|monitor|check|detect)",
  "domain": "safety",
  "category": "system_error",
  "subcategory": null,
  "root_cause": "Confined spaces can accumulate hazardous atmospheres through decomposition, chemical reactions, or displacement of oxygen by inert gases; atmospheric testing with calibrated instruments is mandatory before entry per OSHA 1910.146 and similar regulations worldwide, and visual inspection alone cannot detect these invisible hazards.",
  "root_cause_type": "generic",
  "root_cause_zh": "密闭空间可能通过分解、化学反应或惰性气体置换氧气而积聚危险大气；根据OSHA 1910.146及全球类似法规，进入前必须使用校准仪器进行大气检测，仅靠目视检查无法检测这些无形危害。",
  "versions": [
    {
      "version": "OSHA 1910.146 (2024)",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "ANSI/ASSP Z117.1-2022",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "NFPA 350-2022",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "",
      "why_fails": "This can ignite flammable gases or vapors, causing an explosion; also doesn't detect toxic gases like hydrogen sulfide or carbon monoxide",
      "fail_rate": 0.95,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "Personal monitors require time to stabilize and may not detect stratified gases (e.g., heavy gases at bottom, light at top); also doesn't test all layers of the space",
      "fail_rate": 0.7,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "Atmospheric conditions can change rapidly due to temperature shifts, chemical reactions, or release of trapped gases; testing must be done immediately before entry",
      "fail_rate": 0.85,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Use a calibrated multi-gas monitor (O2, LEL, CO, H2S) with a sampling pump and probe to test the atmosphere at multiple depths: top (0.5m below ceiling), middle (mid-point), and bottom (0.5m above floor) of the confined space before any entry. Wait for readings to stabilize (typically 30-60 seconds per point).",
      "success_rate": 0.92,
      "how": "Use a calibrated multi-gas monitor (O2, LEL, CO, H2S) with a sampling pump and probe to test the atmosphere at multiple depths: top (0.5m below ceiling), middle (mid-point), and bottom (0.5m above floor) of the confined space before any entry. Wait for readings to stabilize (typically 30-60 seconds per point).",
      "condition": "",
      "sources": []
    },
    {
      "action": "Implement a confined space entry permit system that requires documented atmospheric testing results, continuous monitoring during entry, and rescue equipment. Example permit template: 'Atmospheric test results: O2=20.9%, LEL=0%, CO=0ppm, H2S=0ppm. Tested at 08:30 by [name]. Entry authorized until 12:00 unless conditions change.'",
      "success_rate": 0.88,
      "how": "Implement a confined space entry permit system that requires documented atmospheric testing results, continuous monitoring during entry, and rescue equipment. Example permit template: 'Atmospheric test results: O2=20.9%, LEL=0%, CO=0ppm, H2S=0ppm. Tested at 08:30 by [name]. Entry authorized until 12:00 unless conditions change.'",
      "condition": "",
      "sources": []
    },
    {
      "action": "Use a remote inspection camera (e.g., borescope or robotic crawler) to visually inspect the space without entry, combined with atmospheric sampling through a port. This eliminates the need for human entry in many cases.",
      "success_rate": 0.85,
      "how": "Use a remote inspection camera (e.g., borescope or robotic crawler) to visually inspect the space without entry, combined with atmospheric sampling through a port. This eliminates the need for human entry in many cases.",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "Use a calibrated multi-gas monitor (O2, LEL, CO, H2S) with a sampling pump and probe to test the atmosphere at multiple depths: top (0.5m below ceiling), middle (mid-point), and bottom (0.5m above floor) of the confined space before any entry. Wait for readings to stabilize (typically 30-60 seconds per point).",
    "Implement a confined space entry permit system that requires documented atmospheric testing results, continuous monitoring during entry, and rescue equipment. Example permit template: 'Atmospheric test results: O2=20.9%, LEL=0%, CO=0ppm, H2S=0ppm. Tested at 08:30 by [name]. Entry authorized until 12:00 unless conditions change.'",
    "Use a remote inspection camera (e.g., borescope or robotic crawler) to visually inspect the space without entry, combined with atmospheric sampling through a port. This eliminates the need for human entry in many cases."
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.146",
  "official_doc_section": null,
  "error_code": "CONF-ATMOS-001",
  "verification_tier": "ai_generated",
  "confidence": 0.88,
  "fix_success_rate": 0.9,
  "resolvable": "true",
  "first_seen": "2024-03-15",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}