The short version
- Categories A, B and C come from Annex I of Council Directive 92/29/EEC. They are EU law, not a WHO, IMO or ILO standard.
- Category B is measured 150 nautical miles from the nearest port with adequate medical equipment, not from the nearest land.
- The directive binds vessels flying an EU Member State flag. A US-flagged vessel is not bound, and answers to 46 CFR 28.210 instead.
- It also sets a sick bay threshold, a doctor threshold of 100 workers on voyages over three days, five-yearly training and an annual inspection.
- The EU publishes a contents schedule and the United States does not, which is why the categories remain a useful sizing reference for US operators.
Ask a fleet manager where Category A, B and C medicine chests come from and a large share will answer WHO, IMO or ILO. All three are wrong. The categories are EU law, set by Council Directive 92/29/EEC of 31 March 1992, and knowing that changes who they bind and who they do not[1].
That misattribution is not harmless. A chest built to the wrong authority is a chest whose sizing logic collapses the first time an inspector asks which instrument requires it.
Category A, B and C, defined
Annex I of the directive sets three categories, and each is defined by voyage pattern rather than by tonnage or crew size[1].
| Category | Definition in Annex I | What it means in service |
|---|---|---|
| Category A | Sea-going or sea-fishing vessels, with no limitation on length of trips | Deep sea. The fullest chest, because definitive care may be days away |
| Category B | Sea-going or sea-fishing vessels making trips of less than 150 nautical miles from the nearest port with adequate medical equipment | The distance test is to an adequately equipped port, not simply to land |
| Category C | Harbour vessels, boats and craft staying very close to shore or with no cabin accommodation other than a wheelhouse | Shore care is minutes away, so the chest is scaled to stabilise, not to treat |
Read the Category B definition closely. The 150 nautical miles is measured to the nearest port with adequate medical equipment, not to the nearest landfall[1]. A vessel working 120 miles off a coast with no equipped port within that arc is not automatically Category B.
What the category actually controls
The category drives the quantity and range of medical supplies a vessel must carry, against the schedule in Annex II. The directive requires the quantities to reflect the nature of the voyage, the type or types of work, the nature of the cargo and the number of workers[1]. Category is the starting point, not the whole answer.
Three further obligations sit alongside the chest and are routinely missed by operators who treat the directive as a stocking list.
The obligations beyond the chest
Sick bay. Vessels over 500 gross tons carrying 15 or more crew on voyages exceeding three days require a sick bay in which medical treatment can be administered under satisfactory material and hygienic conditions. Doctor. A crew of 100 or more workers on an international voyage of more than three days requires a doctor on board. Training. The captain and designated workers must have special training, updated at least every five years[1].
The directive also requires Member States to designate centres providing workers with free medical advice by radio, and an annual inspection by a competent person or authority to check that supplies comply[1]. That annual interval is worth borrowing even where it does not bind you.
Who is bound, and what a US operator should take from it
The directive defines a vessel as one flying the flag of a Member State or registered under the plenary jurisdiction of a Member State, excluding inland vessels, warships, pleasure boats and harbour tugs[1]. That is the boundary.
| Your situation | Does 92/29/EEC bind you? |
|---|---|
| EU Member State flag | Yes. Category, Annex II supplies, annual inspection and the sick bay and doctor thresholds all apply |
| US flag, trading into EU ports | Not directly. Your obligations are US. Port state inspection still looks at what is on board, so a documented standard matters |
| US operator managing or chartering EU-flag tonnage | Yes, for that tonnage. The flag travels with the hull, not with the head office |
| US flag, no EU trading at all | No. But the categories remain the most usable published sizing logic available, because US law provides none |
One regime publishes a list. The other refuses to.
This is the comparison that matters and no ranking page on this query makes it. Place the EU regime beside the US one and the asymmetry is stark.
| Question | EU, 92/29/EEC | US federal |
|---|---|---|
| Is there a mandated contents schedule? | Yes, Annex II, scaled by category[1] | No. FDA states it has never recommended any particular stocking procedure[3] |
| Is chest size prescribed? | By category and voyage pattern[1] | “A size suitable for the number of individuals on board”, undefined[2] |
| Is there an inspection interval? | Annual, by a competent person or authority[1] | None stated for fishing vessel chests |
| Controlled substances | Handled through national law of the flag state | Prescriptive. 21 CFR 1301.25 governs vessel holdings in detail[6] |
So the two regimes are close to mirror images. The EU specifies the chest and leaves controlled drugs to national law. The United States leaves the chest open and specifies controlled drugs tightly. An operator crossing both needs to satisfy each on its own terms, which is the argument for a single written standard rather than two half-standards. Start from the US position under 46 CFR 28.210 and 21 CFR 1301.25 explained.
The practical consequence lands on the controlled substance file. A vessel that satisfies Annex II in full still has nothing on board that authorises it to hold US-scheduled drugs, because that permission comes only from the US controlled substance regime[6]. If the vessel is US-registered, four separate obligations follow that no EU document covers: the employment test behind the medical officer or master requisition, the recordkeeping rules and how they change by schedule, the route expired stock takes ashore under controlled substance disposal, and the file an inspector asks for, listed in the DEA inspection checklist. Building the chest to Category A and stopping there leaves all four open.
Check whether your source is still in force
Chest-contents queries surface instruments that no longer exist. ILO Recommendation No. 105 of 1958 was withdrawn by the International Labour Conference at its 111th Session in 2023, and still ranks on search results today[7].
The WHO guide has its own trap. The current edition is the third, WHO 2007, with a separate Quantification Addendum published in 2010 carrying the recommended quantities and dosing[4][5]. There is no fourth edition. Listings advertising one are resellers. And the guide is guidance: it grants no authority to hold prescription or controlled drugs.
What to do next
- Establish the flag, then the category. Flag decides whether the directive binds at all. Only then does A, B or C matter[1].
- Write down which instrument you are building to. Name it on the chest document. “Category B per 92/29/EEC Annex I” is defensible. “Standard offshore kit” is not.
- Check every source is in force. One withdrawn recommendation and one non-existent edition are both in circulation[7].
- Run the controlled substance file separately. It answers to the flag state’s national law, and for US registration that means 21 CFR 1301.25 and its two annual reports[6].
- Adopt the annual inspection even where it is not required. The EU sets one, most flags follow, and it is the cheapest evidence you can generate[1].
If the fleet spans several registries, the flag state comparison is the faster route than reading each instrument end to end. For how a chest actually gets built once the standard is set, see how to stock a ship medicine chest, and for how the whole program is examined, the vessel medical compliance audit. Everything else lives in the guidance library and the full service list, and the physicians behind it are on the about page.
Common questions
What are Category A, B and C medicine chests?
They are the three vessel categories in Annex I of Council Directive 92/29/EEC. Category A is sea-going or sea-fishing vessels with no limitation on length of trips. Category B is those making trips of less than 150 nautical miles from the nearest adequately equipped port. Category C is harbour vessels, boats and craft staying very close to shore or with no cabin accommodation other than a wheelhouse[1]. Our MedChest service builds to any of them.
Is the A, B, C system a WHO or IMO standard?
No, and this is the most common error in the topic. A, B and C are EU law under Directive 92/29/EEC[1]. The WHO International Medical Guide for Ships is guidance and uses a different framework[4]. Confusing the two produces a chest built to the wrong authority. Ask us to check which regime applies.
Does 92/29/EEC apply to a US-flagged vessel?
No. The directive reaches vessels flying the flag of, or registered under the plenary jurisdiction of, an EU Member State[1]. A US-flagged vessel answers to 46 CFR 28.210 and to 21 CFR 1301.25 for controlled substances[2]. See the 46 CFR 28.210 rules.
Then why would a US operator care about the categories?
Three reasons. US federal law sets no contents list at all, so an EU category is a published and defensible sizing logic[3]. Many US operators manage or charter foreign-flag tonnage. And EU port state inspection looks at the chest of the vessel in front of it. Our consulting service handles mixed-regime fleets.
How often must an EU chest be inspected?
The directive requires an annual inspection by a competent person or competent authority to check that medical supplies comply[1]. That annual cadence has become the practical norm across flags, including for US operators who have no federal interval at all. See what a vessel medical compliance audit checks.
When does a vessel need a doctor on board?
Under the directive, a vessel with a crew of 100 or more workers on an international voyage of more than three days must carry a doctor responsible for the medical care of the workers on board[1]. Below that threshold the answer is shore-side physician oversight, which is what our consulting line provides.
Is ILO Recommendation No. 105 still the standard for chest contents?
No. ILO Recommendation No. 105 of 1958 was WITHDRAWN by the International Labour Conference at its 111th Session in 2023[7]. It still surfaces on search results for chest-contents queries, which is exactly why sourcing matters. See how to stock a ship medicine chest.
