Hazardous Substances Consent: when you need it and how to apply

 

Hazardous substances consent is a separate land-use planning control for certain dangerous substances in England. It is concerned with the risk created by having specified substances at or above controlled quantities on a site, rather than with whether the buildings or use would otherwise be acceptable in ordinary planning terms.

A site may therefore need hazardous substances consent as well as planning permission, an environmental permit and compliance with COMAH or other safety legislation. One approval does not replace the others.

If the issue is an existing or alleged breach rather than a new application, go straight to our guide to hazardous substances enforcement.

 

What is hazardous substances consent?

 

The system comes from the Planning (Hazardous Substances) Act 1990 and the Planning (Hazardous Substances) Regulations 2015. In simple terms, consent controls whether a specified maximum quantity of a controlled hazardous substance may be present on, over or under particular land.

A consent identifies the land, the substances and their maximum quantities. Conditions can regulate matters such as where and how substances are kept or used, when they may be present and their removal.

The Health and Safety Executive has an important technical role, but the application is normally made to the hazardous substances authority, not to HSE. The Government’s hazardous substances planning guidance is also a useful official companion to the legislation.

 

When is consent required?

 

Consent is required where a controlled substance is present, or is likely to be present, at or above its controlled quantity. The rules look at the maximum quantity which may be present, not merely an average stock level.

Quantities can also be aggregated across an establishment and certain nearby land or structures under the same control. Splitting a substance between tanks or neighbouring parcels therefore does not necessarily keep a site below the threshold.

There are statutory exemptions for particular situations, including some temporary transport or intermediate storage, pipelines, explosives, mineral activities and landfill. There is also a tightly framed rule under which a very small individual quantity below 2% of the controlled quantity can be disregarded where its location means it cannot initiate a major accident elsewhere. It is not a blanket 2% allowance to deduct from every inventory.

The Regulations also allow a limited route for genuinely minor changes where the competent authority agrees that the change has no significant implications for major-accident hazards.

 

Controlled substances and controlled quantities

 

Schedule 1 to the 2015 Regulations contains the detailed list. It uses both hazard categories and specifically named substances, and also deals with substances which may be generated during loss of control of a process.

There is little value in reproducing a long chemical schedule here. In practice you need to establish:

• how each substance is classified under the Regulations
• whether it is specifically named or falls within a hazard category
• the maximum quantity present or likely to be present at any one time
• whether several substances must be aggregated under the statutory formula
• whether a Schedule 2 exemption genuinely applies

If a substance falls into more than one category, the detailed rules determine the relevant controlled quantity. Accurate safety data, process information and a reliable site inventory are therefore essential before an application is prepared.

 

Who is the hazardous substances authority?

 

For most sites the hazardous substances authority is the district, unitary or London borough council which carries out local planning functions. The Act makes special provision for some minerals and waste land, development corporation areas, the Broads and other particular cases.

If the site is unusual, check the correct authority before submitting. The authority is the statutory decision-maker and must exercise its own judgment; HSE advises on safety matters but does not determine the application.

 

How does this relate to ordinary planning permission?

 

Hazardous substances consent and planning permission do different jobs. Planning permission does not authorise controlled hazardous substances above the statutory threshold, while hazardous substances consent does not grant permission for development which otherwise needs planning permission.

Where a project needs both, coordinate the applications so the land-use, safety and environmental issues can be understood together. The hazardous substances authority must have regard to relevant planning permissions, the development plan and current and prospective uses of the application land and surrounding land.

For a large or sensitive project, also consider whether the wider development needs EIA screening or scoping. Environmental impact assessment can include vulnerability to major accidents and disasters, but it does not replace hazardous substances consent.

 

What should an application contain?

 

The 2015 Regulations prescribe the information which must accompany the application. Broadly, expect to provide applicant details, a site map, a plan showing where hazardous substances will be present, details of the land and those controlling it, the substances and maximum quantities, the activities carried on, how and where substances are kept or used and relevant transport information.

The application also requires information about the surrounding area, foreseeable major-accident consequences and measures relevant to limiting those consequences. The statutory plans have specific scale requirements: the site map is generally at not less than 1:10,000 and the detailed substance location plan at not less than 1:2,500.

Ownership certificates and notices are also required. False or recklessly misleading ownership certification is an offence, so land ownership and control should be resolved early.

There is no single prescribed application form which every applicant must now use. HSE provides practical application material, but legally the important point is that the required information, plans, certificates, notices and fee are supplied.

For supporting planning material, see our guides to validation requirements, planning drawings and location and site plans.

 

Publicity starts before submission

 

This is one of the unusual parts of the hazardous substances procedure. The applicant must carry out prescribed publicity in the 21 days before the application is made. The Regulations require publication in a local newspaper or by other appropriate means, which may include electronic publication, and normally a site notice displayed for at least 7 days.

The notice must allow at least 21 days for representations. Evidence and certification of the required publicity then forms part of the application process.

This is not the same as the ordinary council-led neighbour consultation procedure. An applicant should not assume the authority can simply cure defective pre-application publicity later. Our guide to neighbour consultation and publicity explains the normal planning route.

 

Who is consulted?

 

Once a valid application is received, the authority must carry out the consultations required by the 2015 Regulations. The COMAH competent authority is central. For most sites that means HSE and the Environment Agency acting jointly; on relevant nuclear sites the Office for Nuclear Regulation and the Environment Agency have the corresponding role.

Depending on the location and proposal, consultation can also include other local authorities, parish councils, fire and rescue bodies, utilities, Natural England, the Coal Authority, waste authorities and other people or organisations whose interests are likely to be affected.

The authority must allow the statutory consultation period before determining the application. HSE advice is especially significant because the Act restricts the authority’s approach to certain conditions about how and where substances are kept or used without appropriate safety-regulator advice.

If consent is granted, HSE can establish a consultation distance and risk zones around the installation. Those can influence how later development proposals nearby are considered. Our general guide to statutory consultees explains the wider planning system.

 

How is the application decided?

 

The authority can grant consent, grant it subject to conditions or refuse it. A consent identifies the land, the hazardous substances and the maximum quantity of each substance authorised.

The decision must take account of the present and prospective use of the application land and surrounding land, relevant planning permissions and the development plan, together with safety advice and other relevant considerations.

Conditions can regulate how or where substances are kept or used, the times at which they may be present and requirements for removal. They can be coordinated with conditions on related planning permissions, but hazardous substances consent cannot authorise a breach of separate health and safety requirements.

The Regulations prescribe an 8-week determination period for a valid application unless a longer period is agreed in writing. Complex technical cases can take considerably longer in practice. HSE currently tells applicants to allow around 6 to 12 months for an overall consent decision and says its own detailed technical advice to hazardous substances authorities is delivered on a 13 to 26 week service timescale. Those are practical expectations, not replacements for the statutory 8-week period or any written extension agreed with the applicant.

 

Non-determination and deemed refusal

 

For an ordinary hazardous substances application, failure to determine within the prescribed or agreed period gives the applicant an appeal route. Section 21 of the Act treats the application as refused for appeal purposes.

Do not confuse that with a continuation application following a change in control of land. A properly made continuation application can instead be deemed granted if the authority neither decides it nor refers it to the Secretary of State within the prescribed period or agreed extension.

 

Appeals

 

An applicant can appeal where consent is refused, where objectionable conditions are imposed or where the authority does not determine the application in time. Regulation 13 of the 2015 Regulations gives a 6-month appeal period from the decision, or in a non-determination case from expiry of the period in which the authority should have decided the application. The Secretary of State can allow a longer period, but an applicant should never plan on that happening.

This is a specialist appeal under the hazardous substances legislation rather than the ordinary section 78 route. If the same project also has a refused planning application, the two statutory routes remain separate even where evidence overlaps. See our Planning Appeals section for the ordinary planning appeal system.

 

Can an existing consent be varied?

 

Section 13 of the Act allows an application to remove or change a condition attached to an existing hazardous substances consent. The authority considers the condition question and can grant a new consent on the varied basis or refuse the application.

A new substance, a higher maximum quantity or a change outside the existing consent may require a fresh application rather than a simple variation. Before altering a process, layout or inventory, compare the proposed operation with the exact wording and plans of the consent already in force.

 

Change in control of the land

 

Although consent relates to land, sections 17 and 18 contain a specific mechanism where land ceases to be under the control of the person who controlled it when the consent was granted.

In the circumstances covered by section 17, consent can be revoked for the land changing control unless a continuation application is made before the change. The authority can continue the consent, continue it with modifications or revoke it through the statutory process.

This matters on sales, leases, corporate restructures and site subdivision. Due diligence needs to address who controls the relevant land and the timing of completion, not merely whether a consent appears on the public register.

 

Revocation or modification

 

The hazardous substances authority can make an order modifying or revoking a consent where the statutory test is met. The Act expressly addresses material changes in land-use or planning circumstances and cases where a substance has not been present at or above the controlled quantity for a continuous period of 5 years.

The procedure is formal and normally involves confirmation by the Secretary of State, with notice and an opportunity to be heard. Compensation can arise in some circumstances, so this is not simply an administrative deletion from the register.

 

Environmental permits, COMAH and other controls

 

Hazardous substances consent does not replace environmental permitting, COMAH duties, fire safety, workplace health and safety requirements or another licence which the operation needs. Different regimes ask different questions.

• hazardous substances consent controls the presence of specified quantities from a land-use planning perspective
• planning permission controls development and land use
• COMAH is concerned with preventing major accidents and limiting their consequences at qualifying establishments
• environmental permitting controls specified emissions, waste and environmental activities
• other safety legislation controls how the operation must be run

Where several permissions are required, coordinate them, but never assume that approval under one regime answers the others.

 

The public register matters

 

Hazardous substances authorities must maintain a public register containing prescribed information about applications, consents, variations, continuation decisions, revocation or modification and enforcement material.

For a landowner, purchaser or developer, the register is a starting point rather than the whole exercise. Compare the consented substances and plans with what is actually on site, check land control, identify later variations or notices and consider any HSE consultation zones which may affect future development.

 

Offences and enforcement

 

It is a criminal offence to have a controlled quantity of a hazardous substance present without the required consent, to exceed the maximum quantity authorised or to breach a condition. Liability can extend to a person who knowingly causes or permits the contravention and, in appropriate cases, the person in control of the land.

The authority can use a hazardous substances contravention notice and the Act also provides powers including injunctions and direct action. The court can take financial benefit from an offence into account when setting a fine.

Our detailed guide to hazardous substances enforcement and contravention notices covers that side of the regime in full, while the wider Planning Enforcement section explains ordinary planning enforcement.

 

Before you submit

 

• prepare a reliable maximum-inventory schedule rather than relying on average stock levels
• check Schedule 1 classification and aggregation substance by substance
• confirm whether a Schedule 2 exemption genuinely applies
• identify the correct hazardous substances authority
• coordinate planning, environmental permitting and safety-regime workstreams
• allow time for applicant publicity before submission and technical consultation afterwards
• check ownership and control carefully where a sale, lease or site split is planned
• consider how an HSE consultation distance could affect future development around the installation

For the ordinary planning side, the Planning Applications Index, Types of Planning Application and planning fees guides are useful starting points.

Other Planning Application Sections

 

Hazardous substances consent page created: 29th August 2026