Compliance Guide | Permissible Limits | Testing Procedures
Based on WHO / IAEA Guidelines • Applicable to Global Scrap Trade
1. Introduction
Scrap metal recycling is a globally significant industry. However, radioactive contamination of scrap metal poses serious risks to workers, recyclers, and the public. Radioactive materials can enter the scrap stream from industrial equipment, medical devices, or decommissioned nuclear facilities and, if undetected, may be inadvertently melted in steel mills — causing widespread contamination.
Radiation testing is therefore a mandatory step in the responsible handling, trading, and export/import of scrap metal. This guide outlines permissible radiation limits as recognised by the World Health Organization (WHO) and the International Atomic Energy Agency (IAEA), explains how testing is conducted, and details the protocols that must be followed.
2. Why Radiation Testing Matters in Scrap Metal
Radioactive scrap metal incidents have occurred worldwide. When contaminated scrap is melted, radionuclides are distributed throughout the steel product, the dust, and the slag — making decontamination extremely costly and sometimes impossible.
Key concerns include:
- Worker exposure at scrap yards, shredders, and steel mills
- Contamination of manufactured products (rebar, pipes, consumer goods) reaching the public
- Environmental contamination from radioactive dust and slag
- Financial loss — contaminated melts can write off an entire heat (heat = one batch of molten steel)
- Legal liability for importers, exporters, and shippers
- Non-compliance with national and international trade regulations
3. WHO and IAEA Permissible Radiation Limits
3.1 Background Radiation Context
Natural background radiation varies by location but typically ranges from 0.1 to 0.3 microsieverts per hour (µSv/h). Any reading significantly above background should trigger further investigation.
3.2 WHO / IAEA Clearance Levels for Solid Materials
The IAEA Safety Standards Series (Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards — GSR Part 3) and WHO guidelines define clearance levels — below which materials may be released from regulatory control.
| Parameter | Clearance Level | Regulatory Action Level |
| Surface Dose Rate | < 0.1 µSv/h above background | > 1 µSv/h above background |
| Specific Activity (general) | ≤ 0.01 Bq/g (per radionuclide) | > 0.1 Bq/g |
| Activity Concentration (bulk) | ≤ 1 Bq/g (naturally occurring) | Dependent on radionuclide |
| Annual effective dose to public | ≤ 0.01 mSv/year (10 µSv/year) | > 1 mSv/year |
| Occupational dose limit | ≤ 20 mSv/year (averaged over 5 years) | > 50 mSv in any single year |
Source: IAEA GSR Part 3 (2014); WHO Radiation Protection Guidelines.
3.3 Common Radionuclides Found in Scrap Metal
| Radionuclide | Source | Half-Life | Clearance Level (Bq/g) |
| Cs-137 | Medical / industrial gauges | 30.2 years | 0.1 Bq/g |
| Co-60 | Radiotherapy equipment | 5.27 years | 0.1 Bq/g |
| Am-241 | Smoke detectors / gauges | 432 years | 0.01 Bq/g |
| Ir-192 | Industrial radiography | 74 days | 1.0 Bq/g |
| Ra-226 | Oil & gas NORM, antique items | 1,600 years | 0.1 Bq/g |
| U-238 / Th-232 | NORM (naturally occurring) | Billions of years | 1.0 Bq/g (NORM series) |
4. How to Check: Testing Equipment & Methods
4.1 Portal Monitors (Fixed Gate Monitors)
Portal radiation monitors are the industry standard at scrap yards, ports, and steel mills. Trucks or containers pass through the portal; if radiation exceeds the alarm threshold (typically 0.1–0.2 µSv/h above background), the load is flagged for secondary inspection.
- Radiation Portal Monitor (RPM) — fixed gate units
- Vehicle-mounted scanners for mobile inspections
- Container scanners at ports of entry
- Typical alarm threshold: ≥ 0.5 µSv/h above background (ISO 16000 / ANSI N42.35)
4.2 Hand-Held Instruments
| Instrument | What It Detects | Typical Use |
| Geiger-Müller Counter | Beta, gamma radiation | General survey |
| Scintillation Detector (NaI) | Gamma radiation, isotope ID | Identification of radionuclide |
| Proportional Counter | Alpha, beta particles | Surface contamination |
| Dose Rate Meter (Sv/h) | Dose rate measurement | Compliance checking |
| Spectroscopic Identifier (RIID) | Full gamma spectrum analysis | Field identification |
4.3 Laboratory Analysis
Where contamination is suspected or for regulatory compliance, scrap samples may be sent to an accredited laboratory for:
- Gamma spectrometry — identifies specific radionuclides and their activity (Bq/g)
- Alpha/beta counting — for surface contamination
- Inductively Coupled Plasma Mass Spectrometry (ICP-MS) — for trace-level radionuclide identification
5. Step-by-Step Testing Procedure
- Pre-Arrival Preparation: Review documentation (Material Safety Data Sheets, shipper declaration, HS code). Ensure monitors are calibrated (calibration certificate required, typically annual).
- Portal / Drive-Through Scan: Pass vehicle/container through RPM gate. Record dose rate reading. If no alarm — clear for processing. If alarm — proceed to Step 3.
- Secondary Inspection (if alarm triggered): Isolate the vehicle/consignment. Use hand-held Geiger counter to identify the location of the source within the load. Do NOT unload without Radiation Protection Officer (RPO) authorisation.
- Isotope Identification: Use RIID or NaI scintillator to identify the radionuclide. Record spectrum data. Compare against clearance levels in Table (Section 3.2).
- Decision Point: If below clearance levels — consignment is cleared. If above clearance — quarantine load, notify the Radiation Protection Authority (RPA) / national regulator, and follow local regulatory requirements for sealed source recovery, disposal, or return to shipper.
- Documentation & Record Keeping: Record all readings, instrument serial numbers, calibration dates, and actions taken. Issue a Radiation Clearance Certificate for consignments that pass. Retain records for a minimum of 5 years.
6. Applicable International Standards & Regulations
| Standard / Body | Description |
| IAEA GSR Part 3 (2014) | International Basic Safety Standards — defines dose limits and clearance levels |
| IAEA SSG-17 | Specific guidance on monitoring and surveying scrap metal |
| ISO 16000-20 | Detection of radioactive material in recycled metal |
| ANSI N42.35 | American standard for evaluation of RPMs at secure facilities |
| EU Council Directive 2013/59/Euratom | European BSS — applicable in EU member states and export partners |
| BIR Guidelines | Bureau of International Recycling — industry best practice standards |
| ISRI Radiation Guidelines | US Institute of Scrap Recycling Industries — operational protocols |
7. Roles and Responsibilities
7.1 Scrap Dealer / Supplier
- Ensure loads are screened before dispatch
- Provide accurate material declarations
- Do not knowingly supply contaminated material
7.2 Radiation Protection Officer (RPO)
- Oversee all radiation monitoring activities
- Ensure instruments are calibrated and personnel are trained
- Act as the primary point of contact with regulators
7.3 Importer / Mill
- Operate certified portal monitors at entry points
- Maintain records of all screening activities
- Report confirmed contaminated loads to national authority
8. What Happens if Contaminated Scrap is Found?
Upon identification of a radioactive source above clearance levels, the following actions must be taken immediately:
- Isolate the load — cordon off a minimum 3-metre exclusion zone
- Do not attempt to handle the source without specialist equipment and training
- Notify the national Radiation Protection Authority within 24 hours (in most jurisdictions)
- Contact the supplier/exporter with a formal Non-Conformance Report (NCR)
- Arrange specialist Licensed Radioactive Waste Contractor for source recovery
- Complete a full incident report and retain all documentation
Note: In the UK, notification is made to the Environment Agency (EA) and the Office for Nuclear Regulation (ONR). In the US, to the Nuclear Regulatory Commission (NRC). In the EU, to the relevant national competent authority.
9. Summary Checklist
| Checklist Item | Status |
| Portal monitor installed, calibrated, and operational | ☐ |
| Hand-held instruments available and calibrated | ☐ |
| Radiation Protection Officer designated | ☐ |
| Staff trained in radiation awareness and emergency procedure | ☐ |
| Incoming loads screened through portal monitor | ☐ |
| Background radiation level recorded at start of shift | ☐ |
| All alarms investigated and documented | ☐ |
| Radiation Clearance Certificate issued for compliant loads | ☐ |
| Incident reporting procedure in place and known to all staff | ☐ |
| Records retained for minimum 5 years | ☐ |
References: IAEA GSR Part 3 (2014); IAEA SSG-17; WHO Radiation Protection; ISO 16000-20; EU Directive 2013/59/Euratom; BIR Radiation Guidelines. This document is for guidance purposes. Always consult the national regulatory authority in your jurisdiction for legally binding requirements.