Metal Detection in Fulfilment: Which Products Need It and What Retailers Expect

Metal detection in fulfilment is a final check that passes finished products through a detector to find broken needles, staples or other metal fragments before stock reaches a retailer or customer. It matters most for childrenswear, babywear, close-fitting clothing, slippers and filled home textiles, and retailers usually set the requirement in their supplier terms.

Most brands never think about it until a retailer asks. The request usually arrives as a line in a supplier manual or a compliance email, often shortly before a first delivery, and it can stall a listing if there is no way of meeting it. If your products go through a fulfilment partner, the question is whether that partner can carry out the check, record it and fit it into goods in without turning a routine delivery into a project. Fulfil with Synergy carries out metal detection for compliance as part of its value-added services, and this guide sets out what we would want any brand to know before the retailer asks.

What a Metal Detector Actually Checks

A metal detector creates an electromagnetic field, and when a product carrying a metal fragment passes through it, the change in signal triggers an alarm or a reject. SATRA's guidance on avoiding metal hazards in finished footwear explains the two settings that matter: an all-metals mode for products with no metal in them, and a ferrous mode for products with metal parts, used to pick up steel needle fragments.

In a warehouse you will usually see two formats. Conveyor or tunnel detectors handle volume, with each unit passing through in the same orientation. Hand-held detectors are used for spot checks, rechecking a reject and checking items too large or awkward for a tunnel.

Detection is not absolute. SATRA notes that the result depends on the size of the detector opening relative to the product, and on the shape and orientation of the fragment. A needle travelling end-on gives the weakest signal. That is why detectors need regular checks with test pieces, and why the same detector settings rarely suit every product.

Which Products Are Most Likely to Need It

Food production is the best known use of metal detection, but this guide is about sewn and soft goods, where a broken needle can end up against skin. The categories most likely to be named in a retailer requirement are:

• Childrenswear and babywear, including sleepsuits, bath wraps and dressing gowns.
• Close-fitting clothing such as underwear, nightwear and base layers.
• Slippers and children's footwear, where SATRA describes detection as a final check before packing.
• Filled home textiles such as pillows, duvets, bath mats, chair pads and towels.
• Anything sewn or assembled by hand where needles, pins or staples are used on the line.

As an example of how specific a written requirement can be, Kohl's broken needle policy requires factories making its own-brand children's clothing (sizes 0 to 16), filled home textiles and slippers to use a magnetometer on 100% of production, before any metal hardware is fitted, and to keep a needle distribution record that its quality team can ask to see. Kohl's is a US retailer, so treat this as an example of the level of detail, not a UK rule.

What Retailers Usually Want to See

Retailers want evidence that a check took place, at an agreed stage, using a method that is set up and tested properly, with a record they can audit. SATRA notes that many retailers have manufacturing codes of practice for metal contamination and may impose severe penalties on suppliers who fall short.

Requirements differ by retailer and by product, and they are normally set out in the supplier terms or compliance manual you receive when a listing is agreed. When you read yours, look for answers to these points:

• Stage: whether the check must happen at the factory, before dispatch to the retailer's distribution centre, or both.
• Coverage: every unit, or a sample by batch.
• Method: conveyor detector, hand-held detector, or either.
• Testing: how the detector is proved to be working, and how often.
• Records: what has to be logged (date, purchase order, style, batch, result) and how long it must be kept.
• Rejects: who is told, how the unit is held and who decides what happens next.

Never assume a requirement is met because the factory says so. Ask the retailer for its current written requirement, and ask your supplier for evidence of what has already been done.

Where a Warehouse Check Fits

A warehouse check is most useful where the factory record is missing or no longer reflects the product. That happens in four common situations:

• Stock arrives without a reliable record from the supplier, or the record does not cover the whole delivery.
• The retailer wants the check as close to dispatch as possible.
• Goods have been reworked, repacked, re-labelled or kitted after leaving the factory, which adds new handling and new risk.
• Returned or repaired items need checking before they go back into saleable stock.

Agree in writing what is checked, to how many units, what happens to a failure and where the result is recorded, so the warehouse, the brand and the retailer work to the same standard.

What a Warehouse Check Cannot Do

A metal check at the end of the chain is the last line of defence, not a replacement for good control at the factory. SATRA is clear that needles cannot be removed entirely from most sewing processes, so factories need a needle control policy: spare needles kept secure, a new needle issued only when the broken one is handed back, and every fragment accounted for before work restarts.

Metal components are the bigger practical limit. Where a product contains steel shanks or ferrous eyelets, SATRA states that metal detection stops being a valid quality control system, because the detector cannot tell a needle from the trim. Non-ferrous trims make ferrous needles easier to find. This is the reason some retailers, Kohl's among them, require detection before hardware is attached. If your product has steel poppers, rivets or zips, the factory check before trims are fitted may be the only one that counts, and a warehouse check afterwards may not satisfy the retailer.

Packaging matters too. Carton staples, tagging pins and metal clips will all trigger a detector, so agree whether units are checked bare, in polybags or in retail packaging before the job is quoted.

Common Mistakes

The first is leaving it too late. A request that arrives a week before a first delivery rarely leaves time to set up a process, test it on your products and agree the records.

The second is treating it as a one-off. Retailers expect consistency, which means a repeatable method, documented test routines and records for every batch.

The third is mixing checked and unchecked stock, so no one can say which units have been through the process. Once that happens, the safe answer is usually to check everything again.

The fourth is failing to agree what happens when a unit is rejected, including who is told, what is quarantined and who decides on rework or disposal.

Questions to Ask a 3PL About Metal Detection

These questions show quickly whether a provider has done this for retail customers before.

• Do you carry out metal detection in house, and for which product types?
• What equipment do you use, and can it run in a ferrous-only mode for products with metal trims?
• How do you prove the detector is working, with what test pieces and how often?
• Where does the check sit in our flow: at goods in, before storage, during pick and pack or at dispatch?
• What is recorded for each batch, and can we and the retailer see the records?
• How are rejects quarantined, reported and released?
• How do you keep checked and unchecked stock apart in the warehouse system?
• How is the check applied to returns and reworked stock?
• How is it priced: per unit, per batch or per hour?
• Have you worked to this retailer's requirement before?

If you are still shortlisting providers, our comparison of UK 3PLs for value-added services covers who offers which services beyond pick and pack.

How Metal Detection Sits Within Quality Control

Metal detection answers one question, whether there is metal where there should not be, and it says nothing about stitching, sizing, colour or labelling. Brands also need to decide how much general inspection each batch deserves. Our guide to AQL sampling versus 100% inspection explains how to choose between checking a sample and checking every unit. For metal detection on children's products, requirements such as Kohl's cover every unit, because a single missed needle is the failure that matters.

How Fulfil with Synergy Handles Metal Detection for Retail-Bound Stock

Fulfil with Synergy is a founder-led UK third-party logistics (3PL) provider that runs multi-channel, retail and Amazon Seller Fulfilled Prime fulfilment for growing and household brands from purpose-built facilities in Northampton, combining AutoStore automation and the RedPrairie Dispatcher warehouse management system with high-touch services such as kitting, bonded warehousing and returns management.

Metal detection sits within our quality control work. The team carries out inspections at AQL or 100% levels, reports every check, and handles light remedial work such as minor repairs or metal detection for compliance. The value-added services team also prepares stock to each retailer's unit, case and pallet labelling requirements, with bespoke packing lists, delivery dates and bookings, so a metal check, re-labelling and the retailer delivery can be planned as one job rather than three.

Stock is tracked to unit, SKU, batch and location in RedPrairie Dispatcher, with a time-stamped, user-tagged stock movement audit trail. That means checked and unchecked batches can be told apart and you can see where each batch is. For goods that arrive after long sea freight with mould or odour from container condensation, a two-stage Micro-Fresh process can treat the stock before it is re-bagged for compliant dispatch.

Retail work is handled by a long-serving retail and VAS team that works to the operating procedures of most high-street retailers, with dedicated account managers who understand retailer delivery dates and packaging requirements. That is the right place to agree what your retailer needs and how the work is recorded. Our guide to choosing a 3PL for retail compliance and wholesale orders covers the wider checks worth making.

A Preparation Checklist

1. Ask each retailer for its current written metal detection requirement.
2. Ask suppliers for their needle policy, what testing has been done and how it is recorded.
3. List which of your products are in scope, and which have metal trims.
4. Agree with your fulfilment partner where the check happens, how the detector is tested and how results are kept.
5. Agree what happens to a failed unit, and who signs off its release or disposal.
6. Run a small delivery through the process before the first full order.
7. Review the process after the first retailer audit or delivery.

FAQ

Does a warehouse metal check replace the factory's needle control?

No. A metal check at the warehouse is a final safeguard, and it only works well when the factory already controls needles properly. Good factory practice means spare needles are kept secure, a new needle is issued only when the broken one is handed back, and every fragment is accounted for before work restarts. If pieces are missing, garments from that workstation and the ones around it are pulled and checked. Retailers with needle policies, Kohl's among them, expect both: records from the factory and a detection step. Ask your supplier for its needle policy and records, and treat the warehouse check as the layer that catches what slipped through, not the only one.

Can products with zips, poppers or metal trims be metal detected?

Sometimes, but not always reliably. A detector set to find any metal will reject every unit with a metal zip or popper, so products with metal parts are checked in a ferrous-only mode that looks for steel needle fragments and ignores non-ferrous trims such as brass or aluminium. Where the product itself contains ferrous metal, such as steel shanks or iron eyelets, the detector cannot tell a needle from the trim, and the check stops meaning anything. That is why some retailers require detection before hardware is attached. If your product has ferrous components, ask the retailer which stage it accepts before you book warehouse checks.

How often should a metal detector be tested?

As often as your retailer's requirement says, and if it is silent, often enough that a failed test puts only a small amount of stock in doubt. A detector is tested by passing known test pieces through it in the positions that are hardest to detect. If it misses one, every unit checked since the last good test has to be checked again. Testing at the start of each job and after any change of product type keeps that exposure small. Write the routine down, record each test with the batch it covers, and treat frequent false alarms as a sign the detector needs recalibrating.

Who is responsible if a needle reaches a customer?

Under GB product safety rules, the producer carries the primary responsibility: that is the UK manufacturer, a business that puts its own name or brand on the product, or the UK importer. GOV.UK guidance on the General Product Safety Regulations 2005 also says distributors must act with due care, must not supply products they know or ought to know are dangerous, and should be able to show traceability. Your retailer contract may add its own obligations and penalties. This is general guidance, so confirm your position with a product safety adviser or your local trading standards service.

Does Fulfil with Synergy offer metal detection?

Yes. Fulfil with Synergy's value-added services include light remedial work such as minor repairs or metal detection for compliance, carried out by the same quality control team that inspects stock at AQL or 100% levels. Every check is reported. Because Fulfil with Synergy also handles re-labelling, re-ticketing and retailer-specific unit, case and pallet labelling, a metal check can be booked as part of preparing stock for a retailer delivery. Share the retailer's written requirement and a few samples with your account manager before stock arrives, so the stage, testing and records can be agreed first.

If a retailer listing depends on metal detection or other compliance checks, talk to Fulfil with Synergy about setting up the process before your first delivery.

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