CL370 (the “RACE” clause)

Category: Marine and cargo clauses · Reviewed by the Apex broking team · Last reviewed 2026-08-22 · ~3 min read

Definition

CL370 is a short standard-form exclusion published for the London market and attached to a very large proportion of marine cargo, hull and related placements. Its full title is the Institute Radioactive Contamination, Chemical, Biological, Bio-chemical and Electromagnetic Weapons Exclusion Clause, and the current widely used version carries the date 10/11/03. The market shorthand “RACE clause” is taken from the initials of the risks it names — radioactive contamination, and chemical, biological, bio-chemical and electromagnetic weapons — and you will see it written as CL 370, CL370 or the Institute R.A.C.E. clause. All refer to the same wording.

What the clause excludes

The clause excludes loss, damage, liability or expense directly or indirectly caused by, contributed to by or arising from five things. First, ionising radiations from, or contamination by radioactivity from, any nuclear fuel or nuclear waste or from the combustion of nuclear fuel. Second, the radioactive, toxic, explosive or other hazardous or contaminating properties of any nuclear installation, reactor or other nuclear assembly or nuclear component. Third, any weapon or device employing atomic or nuclear fission and/or fusion or other like reaction or radioactive force or matter. Fourth, the radioactive, toxic, explosive or other hazardous or contaminating properties of any radioactive matter. Fifth, any chemical, biological, bio-chemical or electromagnetic weapon.

The isotope carve-out

The fourth limb carries an exception that matters commercially. The exclusion of radioactive matter does not extend to radioactive isotopes, other than nuclear fuel, when those isotopes are being prepared, carried, stored or used for commercial, agricultural, medical, scientific or other similar peaceful purposes. That carve-out is what allows medical and industrial isotope consignments to be insured in the ordinary way. It sits inside limb four only; it does not rescue anything falling within the weapons limbs.

Why “paramount” matters

CL370 is expressed to be paramount and to override anything contained in the insurance that is inconsistent with it. That drafting is deliberate. It means the exclusion is not simply one item in a list to be balanced against extensions, endorsements or all-risks wording elsewhere in the contract; where another term appears to give cover that CL370 takes away, CL370 wins. When you are reading a cargo placement, a paramount clause is the first place to look before relying on a broad insuring clause.

The causation wording

The trigger is wide: “directly or indirectly caused by, contributed to by or arising from”. That formulation is intended to defeat arguments that the excluded peril was only a remote or contributing cause, and it is materially wider than the ordinary proximate cause test that governs the rest of a policy. It is one of the reasons paramount weapons exclusions are so difficult to argue around after a loss.

Where you meet it

CL370 appears as standard on cargo and marine placements alongside the Institute cargo, war and strikes clause sets. Equivalent or near-identical radioactive contamination and weapons exclusions are also used well outside marine business, including on property and liability programmes. A separate, narrower nuclear energy risks exclusion may sit alongside it. Because the wording is standard, the practical questions are usually not about the drafting but about whether the exclusion has been amended, whether any write-back has been agreed for isotope movements, and whether the same exclusion is mirrored in the primary and excess layers.

What to do about it

For most commercial buyers CL370 is not negotiable and does not need to be. The useful checks are narrower: confirm the version attached is the 10/11/03 wording rather than an insurer manuscript variant; if you move isotopes, confirm the peaceful-purposes carve-out has not been deleted; and confirm the exclusion is consistent across every layer and every section, so that a loss cannot fall into a gap between a section that excludes it and a section that is silent. Read it together with the terrorism exclusion, which addresses a different but adjacent set of perils.

Frequently asked questions

Is CL370 the same as a nuclear exclusion?

No. A nuclear exclusion is narrower. CL370 covers radioactive contamination and nuclear devices but also chemical, biological, bio-chemical and electromagnetic weapons, and it is drafted to be paramount over the rest of the contract.

Does CL370 stop me insuring medical isotopes?

Not by itself. The exclusion of radioactive matter has an exception for radioactive isotopes other than nuclear fuel where they are being prepared, carried, stored or used for commercial, agricultural, medical, scientific or similar peaceful purposes.

Can CL370 be deleted?

In practice it is treated as a market-standard paramount exclusion and is very rarely removed. The realistic conversation is about write-backs for specific movements, not deletion of the clause.

Related entries

• Nuclear exclusion
• Terrorism exclusion
• Institute Strikes Clauses (Cargo)
• Institute Cargo Clauses (B)
• Cargo clauses A, B and C: the differences
• Marine Insurance Act 1906

This entry is part of the Apex Insurance Wiki. Position stated as at August 2026. Last reviewed 2026-08-22. Next review: 2027-02-22. It is general insurance information, not legal advice, and not regulated advice on a specific policy.

Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority (FRN 724952). This page is general information, not advice on a specific policy.