Hazardous substances consent or planning permission
A site handling a notifiable substance usually needs both consents. They are granted under different legislation, and a change in control of part of the land can revoke the hazardous substances consent.
Hazardous substances consent and planning permission control different things, and a site handling a notifiable substance normally needs both. Planning permission authorises the development: the tanks, the bund, the compound, the access. Hazardous substances consent authorises the presence of the substance itself, at or above the controlled quantity set out in the Planning (Hazardous Substances) Regulations 2015. One does not imply the other, and granting permission for a storage installation does not entitle anybody to put anything in it.
What hazardous substances consent controls
The consent attaches to the substance and the quantity, not to the building. It is required where a hazardous substance is to be present on, over or under land in a quantity equal to or exceeding the controlled quantity for that substance.
Three features distinguish it from planning permission.
It is quantity based. The trigger is the maximum quantity that may be present at any one time, so a site can hold a listed substance indefinitely without consent provided it stays below the threshold, and a single delivery that takes it over the line puts the operator in breach.
It is substance specific. The consent identifies the substance, the maximum quantity and the location on the site. Swapping to a different substance, or increasing the quantity, needs a fresh application.
And it is granted by the hazardous substances authority, which for most sites is the same district or unitary council that is the local planning authority, acting under different legislation with a different application form, a different fee and different publicity requirements.
Controlled quantities and how the threshold works
Schedule 1 to the 2015 Regulations lists named substances and generic categories, each with a controlled quantity in tonnes. Named substances include materials such as liquefied petroleum gas, chlorine and ammonia. The generic categories cover classified hazards, so a substance that is not named individually may still be caught by its classification.
Read the Schedule rather than any summary of it, because three rules decide most borderline cases. Quantities aggregate across the whole of an establishment rather than per vessel. Substances in different categories are combined using an addition rule, so several sub-threshold materials can together exceed a controlled quantity. And the figure is the maximum quantity liable to be present, which for a site taking regular deliveries means the peak after a delivery and not the average stock.
Get this calculation checked by someone who does it routinely. The commonest error is counting the usable contents of a vessel rather than its capacity, and the commonest consequence is operating without a consent for two years and discovering it during a sale.
The Health and Safety Executive's two roles
The Executive appears twice in this area and the two roles are easily confused.
On an application for hazardous substances consent it is a statutory consultee. It assesses the risk the proposed substance and quantity would present at that location and advises the hazardous substances authority. Where the authority is minded to grant consent against advice, it has to notify the Executive before doing so.
On applications for planning permission for development near an existing notified site, it is consulted where the proposal falls within the consultation distance around that site. There it advises either against the development or that it does not advise against, using an assessment that considers the type of development, the number of people likely to be present and their vulnerability. A hospital, a school or a care home is treated very differently from a warehouse with four staff.
That advice is not a veto. The authority can grant permission against it, and some do, but it must notify the Executive first and the decision then carries an obvious weight of justification. In practice an advice against is close to decisive on a sensitive use.
Consultation distances and development nearby
Consultation distances are set around notified installations and are published through the Executive's land use planning service. They are not visible on a standard constraints search, which is how developers discover them late.
Check at the site selection stage. If you are promoting a residential allocation, a school site or a care home within a consultation distance, the societal risk assessment can reduce the developable area, dictate the position of the most sensitive uses within the site, or remove the site from consideration entirely. None of those outcomes improves with time.
Where the proposal is itself large enough or sensitive enough, the risk case may need to feed into a formal environmental assessment. An Environmental Impact Assessment must be prepared by competent experts under the Town and Country Planning (Environmental Impact Assessment) Regulations 2017, so an AI-assisted draft is a starting point for that team rather than a substitute for it. Major accident risk is one of the matters an environmental statement has to address where the regulations apply.
The distinction between a public law consent and a private law constraint is worth keeping straight here, in the same way that a planning condition and a restrictive covenant do different jobs, as our note on restrictive covenant or planning condition sets out.
Deemed consent, revocation and changes of control
Hazardous substances consent runs with the land, like planning permission, and it is subject to one trap that planning permission does not have.
Where there is a change in the person in control of part of the land to which a consent relates, the consent is revoked unless an application has been made to the hazardous substances authority for its continuation. This is a live risk on any site disposal, lease of part, or corporate reorganisation that splits an establishment. Deal with it in the sale documents, not afterwards.
The authority can also revoke or modify a consent, including where the substance has not been present for a period, and there is a compensation regime attached to some of those decisions. Historic deemed consents exist for substances present before the regime applied, claimed during a window that has long closed. If a site relies on one, obtain the paperwork during due diligence rather than taking the operator's word for it.
Running both consents for one site
A new installation needs the two applications run in parallel. They go to the same council, usually to different officers, and the determination periods differ.
The planning application covers the development in the ordinary way: siting, scale, appearance, access, drainage, landscape and amenity, supported by a Planning Statement addressing the development plan. Tanker movements and the junction capacity are frequently the contentious planning issue rather than the substance itself, so a Transport Statement covering vehicle numbers, routing and the swept path at the access answers the highway authority's first question.
The consent application covers the substance. Neither application determines the other, and it is possible to end up with consent for a substance and no permission for the vessel to hold it, which is why they should be submitted together and tracked together.
Separately, the Control of Major Accident Hazards Regulations 2015 impose duties on operators of lower and upper tier establishments, enforced by a competent authority rather than by the planning system. Those duties are not a planning matter and a planning permission says nothing about compliance with them.
The evidence each application needs
| Application | What it has to contain |
|---|---|
| Hazardous substances consent | The substance, its classification, the maximum quantity liable to be present, a plan showing where on the site it will be and in what vessels, a description of the site and the surrounding area including nearby population and sensitive uses, and the prescribed fee |
| Planning permission | Site location plan, site layout, elevations and sections of tanks and bunds, access and tracking drawings, drainage including bund capacity and firewater containment, landscape mitigation, and the usual certificates |
Both applications are publicised, and both attract local attention, which is a reason to prepare the communications material once and use it for both.
One honest uncertainty. The consultation distances and the assessment method the Executive applies are reviewed from time to time, and a site that was acceptable under an earlier methodology may not be under the current one. Check the current position with the Executive's land use planning service at the outset rather than relying on a historic consultation response in the file.
If you are scoping the evidence base for a site of this kind and want to see which supporting documents it is likely to need, enter the postcode on PlanScope and work through the constraints first.
This is general guidance, not legal advice, so check the position with your local planning authority, the hazardous substances authority or a qualified professional before relying on it. For specialist technical reports, qualified professional input may be required. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Who grants hazardous substances consent?
The hazardous substances authority, which for most sites is the same district or unitary council that acts as local planning authority. It works under the Planning (Hazardous Substances) Act 1990 and the 2015 Regulations, with a separate application form, fee and publicity requirements from a planning application.
How is the controlled quantity calculated?
From the maximum quantity liable to be present at any one time across the whole establishment, not per vessel and not as an average. Substances in different categories are combined using an addition rule, so several sub-threshold materials can together exceed a controlled quantity. Vessel capacity rather than usable contents is the figure that counts.
Can a council grant permission against HSE advice?
Yes, but it must notify the Health and Safety Executive before doing so. The advice is not a veto. In practice an advice against development is close to decisive where the proposal is a school, hospital, care home or housing, because the societal risk case is hard to answer on a sensitive use.
Does hazardous substances consent transfer with the land?
It runs with the land, with one important exception. Where there is a change in the person in control of part of the land to which the consent relates, the consent is revoked unless an application for its continuation has been made to the hazardous substances authority. Deal with this in the sale or lease documents.
How do consultation distances affect a residential site?
Development within a consultation distance around a notified installation triggers consultation with the Health and Safety Executive, and the assessment weighs the type of development, the number of people present and their vulnerability. It can reduce the developable area, dictate where the most sensitive uses sit, or rule the site out.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.