The tests above determine whether or not someone may remain within a liability group. Because in its nature a liability group may have more than one person, some mechanism is necessary to decide how costs of remediation will be apportioned within the group. Again different formulas are in place for class A and class B appropriate persons. In relation to class A appropriate persons, the local authority should seek reasonable information, and in particular consider any relevant information provided by members of the liability group. The Guidance suggests a five-stage process in which:
1. Potential appropriate persons are identified;
2. The necessary remediation actions are characterised;
3. Responsibility is attributed among the group;
4. Exclusions are applied;
5. Liability is apportioned between remaining members.
It is also instructed by the guidance to notify members of the group of the intended apportionment and it is suggested that this may be done at the time of consultation prior to the service of a remediation notice.
From the Class A liability group, the local authority should assess the relative liabilities of any liability group. Taking into account the involvement with pollution, questions of foreseeability, and any power to prevent or remove contamination. Under these tests it might be thought that those knowingly permitting might face a lesser liability (not having caused the presence) but the guidance suggests that they will be treated no more leniently in terms of apportionment the remainder of the liability group, and that they may even face an increased burden. Thereafter it should apportion costs on the basis of the contribution made by those different persons in the group/sub-group to the circumstances that now give rise to the need for remediation. Where the local authority has insufficient information upon which to act, it is instructed to apportion costs equally.
The issues raised above are well illustrated by the appeal involving the so called ‘Sandridge’ site in Hertfordshire. In November 2005 the Environment Agency identified Crest Nicholson and Redland Minerals Limited (which had acquired the original polluting company, Steetley Chemicals, in 1992) as the “appropriate persons” for the service of a remediation notice under Part IIA. They appealed to the Secretary of State for the Environment under section 78L against the service of the notices. Crest felt aggrieved that having bought a site for development, but never having caused the presence of pollution, it should bear a significant share of the liability cost. However, the Secretary of State ruled that: “as a result of action and inaction in the way it dealt with the site [Crest] caused contaminants that would otherwise have been removed to remain and also caused contaminants to be flushed deeper and faster into the ground”.
In determining relative contributions three factors are to be taken into account, namely the quantities of pollutant present, or where this is not clear, the different time periods of occupation, or, in certain cases, the areas of the site occupied by parties in the liability group. In addition to looking at relative contribution in relation to these factors, the local authority can take into account the factors that may have led to a party being excluded from the liability group but which proved insufficient to do so in the particular case. As for apportionment, where there are only class B parties, costs may be apportioned on the basis of the relevant areas of land that the parties own or occupy. Where members of the liability group had different beneficial interests then it is presently suggested that costs be apportioned in proportion to the relative capital value of those interests.
On any site it is possible to have more than one pollution linkage. It may be that each pollution linkage is best dealt with separately, apportioning the costs between the liability group for that linkage. However it may be that a programme of remediation may benefit a number of pollution linkages. Where this is so, no liability group can be made to pay more than it might need to pay in respect of its own pollution linkage. However, there may be economies of scale – even to the point that it will be unnecessary to call upon a class B liability group to contribute. So where a remediation is a ‘shared action’ (i.e. it will clean-up more than one pollution linkage) then any ‘common action’ within the remediation programme is to be apportioned equally between class A group(s) where these exist and class B groups where there are no class A persons to be found.
It is also possible to have a ‘collective action’ that is a remediation programme which addresses the whole of the significant pollution linkages on the site at once – perhaps thereby adopting a course of action which would not have been used for one of the single linkages had it stood alone. Here costs will be apportioned across the liability groups for each pollution linkage but rather than divided equally, they should be apportioned in accordance to the estimates of what the liability group would have faced if its pollution linkage had been addressed alone. It is open, however for a liability group to make out the case that the liability which they face on this basis is disproportionate, and if so persuaded, the authority will be required to adjust the formula. Using this formula it may be possible to recover some of the cost necessary to pay for remediation of an ‘orphan linkage’ but it is not possible to outstrip the limits of estimated liability for each pollution linkage.