Material stockpiles on site: when is a permit, dispersion study, or expert opinion needed?

Why material stockpiles on site should not be underestimated

A material stockpile on site is often treated as an ordinary operational area. The operator stores aggregate, soil, recycled material, slag, sand, gravel, building materials, or other bulk raw materials on site and assumes that if it is not a production line, nothing needs to be addressed.

From the perspective of air protection, that may not be true. An open storage area can be an area source of dust. Emissions arise not only during storage itself, but also during weighing, unloading, loading, transfer, vehicle movements, wind erosion, and contamination of internal site roads.

The problem most often appears during an inspection by the Czech Environmental Inspectorate (ČIŽP), when operations change, in operating permit proceedings, EIA, applications to change integrated permits, building proceedings, or complaints from nearby residents. At that point it is no longer enough to say in general terms that material has always been stored on site. What matters is demonstrating whether the specific area, type of material, and handling method are actually permitted.

A described area is not the same as a permitted area

In practice there is an essential difference between a stockpile being shown on a site plan and it actually being permitted as part of operation of an air pollution source.

Operators often have an old operating permit, operating rules, or integrated permit in which storage areas are stated in general terms. During an inspection, however, it may turn out that the actual situation is broader: different materials are stored, the stockpile is larger, handling takes place on a different area, crushers or screens have been added, traffic has increased, or material has been moved closer to the site boundary and residential development.

What usually matters most is the operative part of the decision. If the permit decision clearly states what is permitted, what the capacity is, where the source is located, and under what conditions it is to be operated, one cannot rely only on a general description in the reasoning or on an old map annex. The reasoning helps with interpretation, but on its own it usually does not replace a missing permit for a specific activity.

Practical note: During an inspection it is not enough to show that some storage area exists on site. It is necessary to verify whether the operating permit actually covers the given type of material, total stockpile area, handling method, operational capacity, transport, and dust control measures.

When a stockpile may fall under a listed source

For standalone open stockpiles of bulk materials it is necessary to check especially Annex No. 2 to Act No. 201/2012 Coll., on air protection. Code 12.1 concerns handling of bulk materials including their storage on open areas, where it is a source not listed elsewhere and the total designed stockpile area is 3,000 m² or more. Construction sites are an exception.

The phrase not listed elsewhere is important. If storage or handling is part of another technology, for example an asphalt plant, concrete plant, quarry, recycling line, landfill, cement plant, or other listed activity, it may not be assessed in isolation only under code 12.1. It is necessary to determine under which code the entire source is classified and whether storage and handling areas are part of that permitted source.

In unclear cases it is not appropriate to decide only by the name of the area in the site plan. What matters are design parameters, the actual purpose of the area, type of material, degree of dustiness, capacity, intensity of handling, and links to other technologies.

When an operating permit is needed

An operating permit is needed when the stockpile or material handling meets the characteristics of a listed stationary source under the Air Protection Act, or when it is part of another listed source that requires an operating permit.

It is typically advisable to verify an operating permit in the following situations:

The most common mistake among operators is assessing only the stockpile area itself. In reality the entire related operation must be evaluated: storage, loading, unloading, transfers, loader movements, heavy vehicle traffic, road cleaning, and technical dust control measures.

When a dispersion study may be needed

A dispersion study is usually prepared when it is necessary to assess the impact of a source on air quality in the surroundings. For stockpiles, contributions of particulate pollutants are most often addressed, especially PM10 and PM2.5. A study may be needed for a new source location, permit change, capacity increase, change in storage scope, or in proceedings where it is required by law, the regional authority, the Ministry of the Environment (MŽP), or a subsequent permitting process.

For area dust sources it is important that the calculation does not depend only on area size. Inputs must correspond to actual operation. The type of material, grain size, moisture, active area size, stockpile height, frequency of handling, number of loadings and unloadings, vehicle movements, transport, dust control measures, and distance to residential or other sensitive development are assessed.

A dispersion study may be needed especially if the source is in a locality with increased immission load, near residential buildings, schools, healthcare facilities, or where complaints about dust already exist. For operational changes it is essential to assess whether the change increases emissions or contribution to pollution levels.

When an expert opinion is prepared

An expert opinion is used as a technical supporting document for permitting or changing operation of a listed source. For stockpiles and storage areas it makes sense especially where it is necessary to describe the source professionally, evaluate its classification, propose operating conditions, and assess whether the proposed measures meet air protection requirements.

An expert opinion should not be a formal annex without connection to actual operation. For dusty operations it is important that it addresses specific measures: wetting, minimising drop height, covering, surface stabilisation, road cleaning, limiting handling in adverse weather, traffic organisation, and control of compliance with operating conditions.

For older sites an expert opinion can also help compare permitted and actual state. This is practical especially when the operator does not know whether to apply for a permit change, supplement operating rules, or first prepare new technical supporting materials.

What the operator must check in their own permit

First it is necessary to take the current operating permit, or integrated permit if applicable, and compare it with the actual state on site. It is not enough to check only the source name. It is important to read the operative part of the decision, operating conditions, and annexes expressly referred to in the operative part.

The operator should check mainly whether the permit clearly states the type of stored material, stockpile area, capacity, location, handling method, operating hours, dust control measures, and related transport. If the permit states, for example, storage of aggregate on a certain area, that does not automatically mean that storage of fine recycled material, area increase, or relocation of the stockpile elsewhere on site is permitted.

Older permits with general wording deserve special attention. If the decision does not describe storage areas with sufficient precision, during an inspection it may be disputed whether the current state is still within the permit. In such a case it is advisable to prepare technical supporting materials in advance and assess whether a permit change is needed.

Most common mistakes in practice

The most common mistake is the belief that a stockpile is permitted simply because it has been on site for a long time. Long-term use in itself does not prove that the area is correctly covered in the operating permit under current requirements.

A second frequent mistake is working with an outdated site plan. Storage in the site is often moved according to operational needs, but the permit, operating rules, and map remain original. During an inspection a difference then arises between permitted and actual state.

A major problem is also insufficient description of the material. From the perspective of dustiness it is not the same to store moist soil, coarse aggregate, dry recycled material, fine fraction, or ash. If documentation states only the general term bulk material, it may not be clear what emissions and what measures should have been assessed.

Another mistake is underestimating transport and vehicle movements on site. For stockpiles, heavy vehicles and loaders, road contamination, and dust resuspension often contribute significantly to dustiness. If the dispersion study or permit addresses only the material pile itself, the assessment may be incomplete.

What supporting materials to prepare

For an initial assessment the most important thing is to compare documentation with actual state. Ideally prepare a current site plan showing individual stockpiles, handling areas, entrances, internal roads, loading and unloading points, and the nearest residential or other sensitive development.

It is also necessary to add types of materials, area sizes, approximate quantities stored, operating regime, frequency of handling, number of vehicles, equipment used, and existing dust control measures. For permitting proceedings it is advisable to have project documentation, operating rules, previous expert opinions, dispersion studies, regional authority decisions, and any statements from ČIŽP or the regional hygiene station (KHS).

If operation has changed gradually, it is also advisable to prepare a brief description of development: for example when a new area was created, when the type of material changed, when a sorting line was added, when capacity increased, or when the transport route on site changed.

What dust control measures may be needed

For stockpiles a general statement that the operator will limit dustiness is not enough. Measures must be technically feasible, controllable, and proportionate to the type of material and operation.

In practice the following are mainly addressed: stabilisation and cleaning of surfaces, wetting, limiting drop height during loading and unloading, suitable orientation and height of stockpiles, covering or partial covering, limiting handling in strong wind, road cleaning, control of vehicle contamination, and separation of dusty activities from the site boundary.

During permitting it is important that these measures are not only in the general part of documentation, but are reflected in binding operating conditions where necessary. Otherwise it may be difficult to demonstrate what specific obligations the operator must fulfil and how compliance will be monitored.

What you can send us for assessment

For a quick assessment send the current operating permit or integrated permit, operating rules, site plan, description of stored materials, approximate stockpile area, site photographs, and information on how material is handled. If there is already a requirement from the regional authority, ČIŽP, building authority, or EIA processor, send that communication as well.

It is also useful to indicate what you consider the current state and what is a planned change. Otherwise supporting materials for original operation, current reality, and future intention may become mixed up.

We will verify whether the stockpile is adequately addressed in the operating permit, whether it may be a listed source, and whether a permit change, dispersion study, expert opinion, or update of operating rules is needed. In disputed cases we recommend assessing supporting materials in advance, before a problem arises during an inspection or in subsequent proceedings.

Brief summary

A material stockpile on site can be a significant source of dust from the perspective of air protection. What matters is not only that it is a storage area, but also the type of material, total area, handling method, transport, location on site, and links to other technologies.

The operator should first verify whether actual state corresponds to the operative part of the operating permit. If a different material is stored, the area has increased, stockpile location has changed, or handling has been added, a permit change, dispersion study, expert opinion, or supplement to operating conditions may be needed.

The greatest risk arises where documentation describes a different state from what is actually operated on site. For dusty operations it is therefore advisable regularly to compare the permit, operating rules, site plan, and real operation.

Factual basis of the article

From these supporting documents it follows that for stockpiles it is not enough to assess only area size. The entire operational whole must be assessed: material, handling, transport, dustiness, emission control measures, and compliance with the permit. If any part of operation is described imprecisely or is missing from the operative part of the decision, it may be advisable to prepare a permit change and supplement technical supporting materials before the matter is opened during an inspection.