112.—(1) If it appears to a council that—
(a)there has been a material change of use of land to which a hazardous substances consent relates; or
(b)planning permission has been granted for development the carrying out of which would involve a material change of use of such land and the development to which the permission relates has been commenced,
it may by order—
(i)if the consent relates only to one substance, revoke it;
(ii)if it relates to more than one, revoke it or revoke it so far as it relates to a specified substance.
(2) A council may by order—
(a)revoke a hazardous substances consent which relates to only one substance if it appears to the council that that substance has not for at least 5 years been present on, over or under the land to which the consent relates in a quantity equal to or exceeding the controlled quantity; and
(b)revoke a hazardous substances consent which relates to a number of substances if it appears to the council that none of those substances has for at least 5 years been so present.
(3) A council may by order revoke a hazardous substances consent or modify it to such extent as it considers expedient if it appears to the council, having regard to any material consideration, that it is expedient to revoke or modify it.
(4) An order under this section must specify the grounds on which it is made.