Dangerous Goods Classification by Substance or UN Number

{
  "type": "object",
  "required": [
    "substance"
  ],
  "properties": {
    "substance": {
      "type": "string",
      "description": "Substance name or UN number (e.g. UN1203, Gasoline)"
    }
  },
  "additionalProperties": false
}

{
  "type": "object",
  "properties": {
    "error": {
      "type": "string",
      "description": "Present only when the submitted substance does not resolve to any known classification; human-readable guidance on how to retry (e.g. try a UN number or a known substance name)."
    },
    "match": {
      "type": "object",
      "properties": {
        "class": {
          "type": "string",
          "description": "Hazard class number, e.g. '3' for flammable liquids."
        },
        "labels": {
          "type": "array",
          "items": {
            "type": "string"
          },
          "description": "Hazard label codes to display on packaging, e.g. ['3']."
        },
        "division": {
          "type": "string",
          "description": "Hazard sub-division. Observed as an empty string on the one matched fixture captured, where the class has no further sub-division."
        },
        "erg_guide": {
          "type": "string",
          "description": "Emergency Response Guidebook guide number, e.g. '128'."
        },
        "un_number": {
          "type": "string",
          "description": "e.g. 'UN1203'."
        },
        "packing_group": {
          "type": "string",
          "description": "e.g. 'I', 'II', 'III', indicating packing stringency."
        },
        "limited_quantity": {
          "type": "boolean",
          "description": "Whether the substance qualifies for limited-quantity shipping exceptions."
        },
        "marine_pollutant": {
          "type": "boolean"
        },
        "subsidiary_risks": {
          "type": "array",
          "items": {
            "type": "string"
          },
          "description": "Additional hazard classes that apply alongside the primary class. Observed as an empty array on the one matched fixture captured; a populated item's shape is unconfirmed."
        },
        "class_description": {
          "type": "string",
          "description": "Plain-language name of the hazard class."
        },
        "special_provisions": {
          "type": "string",
          "description": "Free-text handling and safety notes, e.g. flash point and vapor-density warnings."
        },
        "proper_shipping_name": {
          "type": "string",
          "description": "The substance's regulatory shipping name, e.g. 'Gasoline / Petrol / Motor spirit'."
        }
      },
      "description": "Present only when the submitted substance resolves to a known dangerous-goods classification. Absent when no match is found (see `error`/`matches`/`total_matches` instead).",
      "additionalProperties": true
    },
    "query": {
      "type": "string",
      "description": "The substance name or UN number exactly as submitted, echoed back."
    },
    "matches": {
      "type": "array",
      "items": {},
      "description": "Present on an unmatched query. Observed as an empty array on the one unmatched fixture captured; a populated item's shape is unconfirmed."
    },
    "total_matches": {
      "type": "number",
      "description": "Count of candidate matches found. Observed 0 on an unmatched query."
    }
  },
  "description": "The dangerous-goods classification result, as returned at routing.responseResultPath ($.output).",
  "additionalProperties": true
}