Development near a major hazard site or pipeline

If your site falls within a consultation distance around a major hazard installation, a licensed explosives site or a major accident hazard pipeline, the local planning authority has to consult the Health and Safety Executive before determining the application. The advice that comes back is either "advise against" or "do not advise against", and it is advice rather than a veto. But an authority minded to grant permission against it has to notify the regulator and wait before issuing the decision, and most authorities will not take that step without a very good reason. So the time to find out is before you buy the land.

Consultation zones and what sets them

Consultation distances are set by the Health and Safety Executive around each notified installation and pipeline, based on the substances held, the quantities and the containment. They are not a single ring. There are normally three zones, an inner, middle and outer, with the advice becoming less restrictive as you move outwards.

The second variable is what you propose. Development is sorted into sensitivity levels, from the least sensitive, such as workplaces and parking, through housing and hotels, to institutional uses such as schools, hospitals and care homes, and then to large scale sensitive development. The advice is the intersection of the zone and the sensitivity level.

That structure explains an outcome that surprises developers. The same site can take a light industrial unit without comment and attract an objection to a block of flats, or take 20 flats and attract an objection to 200. It is not the site that is being assessed. It is the population you are putting on it.

How to check whether a site is inside a zone

Four checks, and do them in this order.

1. Ask the local planning authority. Authorities hold the consultation distance information for their area and will usually tell you on an informal enquiry, which costs nothing.
2. Use the regulator's own land use planning advice tool, which returns the advice for a proposed development at a given location.
3. For pipelines, contact the operator directly. Pipeline routes are not always obvious on the ground, and the building proximity distance for a high pressure pipeline can extend well beyond the easement.
4. Check the title for easements and deeds of grant. A pipeline easement typically prohibits building, deep rooting planting and changes of level within a defined strip, and that restriction binds you whatever the planning position.

Where a site adjoins an industrial estate with no obvious hazard, check anyway. Chlorine at a water treatment works, ammonia at a cold store and liquefied petroleum gas at a depot all generate consultation distances, and none of them is visible from the road.

The advice and the weight it carries

Advice against development is a material consideration of considerable weight, because it comes from the body with the statutory function and the technical basis for it.

The waiting period exists so the regulator can consider whether to ask for the application to be called in. In practice very few are, and the more common outcome is that the authority decides it is not prepared to grant against the advice.

Where the consultee response is slow, the position is the one described in our note on appealing non-determination or waiting, and on a hazard consultation waiting is almost always the better choice, because an appeal against non-determination with an unresolved objection from a statutory consultee is a poor appeal.

Development types most affected

Housing is the common case, because it puts a resident population inside a zone for 24 hours a day. Care homes, schools, nurseries and hospitals attract tighter advice because the occupants are less able to evacuate. Large retail, stadia and outdoor assembly bring high transient populations.

Two categories produce more applications than the rest. Residential conversions of industrial buildings inside established industrial areas, where the hazard installation was there first. And infill housing on the edge of a works that has reduced its inventory but not its notification.

That second case is worth pursuing. Consultation distances follow the notified inventory, and operators sometimes hold notifications for substances in quantities they no longer keep. If the inventory really has reduced, the operator can revise the notification and the distance may change with it. That takes months and depends entirely on the operator's cooperation, so treat it as a long shot rather than a plan.

Pipelines and their easements

Major accident hazard pipelines are a separate and more common constraint than the fixed installations, because they run for hundreds of kilometres through land that otherwise looks unconstrained.

Three distinct restrictions apply, and conflating them causes trouble. There is the easement, which is a property right restricting what you can build and plant. There is the building proximity distance used for land use planning advice, which is usually wider than the easement. And there is the operator's requirement for a crossing or works agreement where you need to put a road, a drain or a service across the line.

Get written confirmation of all three before the layout is fixed. A scheme that puts the attenuation basin over the pipeline, or the estate road across it without an agreement, is a scheme that gets redrawn during technical approval, and our note on getting consultee responses and the officer's case file sets out how to extract that confirmation in usable form.

Designing to reduce the population at risk

Where a site is partly within a zone, the layout is the answer rather than the argument.

Put the least sensitive uses closest: parking, landscape, attenuation, storage, workshops. Keep residential density lower towards the hazard and higher away from it. Avoid any use with an institutional population inside the inner zone at all. Where a scheme has a community or commercial element, locate it where it reduces rather than adds to the population at risk.

Then present it properly. A plan showing the zone boundaries, the numbers of people associated with each part of the scheme, and the comparison with the previous lawful use, is far more persuasive than an assertion that the risk is low. Where the site has an existing industrial use with a daytime workforce, the change in population may be smaller than it looks.

Risk of major accidents also enters the environmental impact assessment regime. The 2017 Regulations require the likely effects of a development's vulnerability to major accidents and disasters to be considered where environmental impact assessment applies, so on a larger scheme the hazard proximity needs addressing in the environmental statement as well as in the consultation response.

A Planning Statement for a site in a consultation zone should deal with the point head on: which installation or pipeline, which zone, the sensitivity level of the proposal, the population comparison, and the layout response. Burying it in an appendix invites a late objection.

As an illustrative example, a four hectare site where the inner zone clips the eastern third might take surface parking, the attenuation basin and a terrace of workshops on that third, with housing on the western two thirds, and no nursery or care use anywhere on the site. Same unit numbers, different plan, different advice.

Check the hazard position at the option stage, before you spend anything on design. This is general guidance rather than legal advice, so confirm the position with your local planning authority, the regulator and the asset owner before relying on it. To see which documents a site like this needs, browse the report types by category. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.