casquery

Query the EPA Substance Registry Service (SRS) using CAS Registry Numbers (CASRN).

casquery provides:

• A command-line tool for searching CASRN records
• Normalization of messy CAS numbers
• CAS resolution (superseded → current CASRN)
• Batch processing of CSVs
• Multiple output formats (table, JSON, XML, CSV)

It works both as:

• A standalone script (python casquery.py)
• A PyPI-installable CLI (casquery …)

Installation

# From PyPI
pip install casquery
# Or pip install git+
pip install "git+https://github.com/geocoug/casquery.git"

Command Line Usage

# Help
casquery --help
casquery search --help

# Search EPA SRS
casquery search 375-73-5 29420-43-3

# Search with synonyms
casquery search --synonyms 375-73-5

# Output formats
casquery search 375-73-5 --format json
casquery search 375-73-5 --format xml
casquery search 375-73-5 --format csv

# Normalize CAS numbers
casquery normalize 1234567
# → 1234-56-7

# Resolve superseded CAS numbers
casquery resolve 29420-43-3

# Batch-process a CSV (Input CSV must contain a column of CASRN values.)
casquery batch input.csv --column analyte_cas --output cleaned.csv

Examples

Search for two CAS numbers

casquery search 7440-66-6 7440097

╭───────────────────────────────────────────────╮
│        EPA SRS CASRN Search Results           │
╰───────────────────────────────────────────────╯
cas_rn     systematicName     epaName     currentCasNumber
---------  ------------------  ----------  -----------------
7440-66-6  Zinc                Zinc        7440-66-6
7440-09-7  Potassium           Potassium   7440-09-7

Output JSON instead of a table

casquery search --format json 7440-66-6 7440-09-7

[
  {
    "cas_rn": "7440-09-7",
    "systematicName": "Potassium",
    "epaName": "Potassium",
    "currentCasNumber": "7440-09-7"
  },
  {
    "cas_rn": "7440-66-6",
    "systematicName": "Zinc",
    "epaName": "Zinc",
    "currentCasNumber": "7440-66-6"
  }
]