My hon. Friend has drawn attention to what, it will be admitted, is an extremely difficult problem, and I would not seek to minimise it in any way. Dust is a very great evil, and I am sure that to those who live in these areas it must be highly annoying. I would not want it to be thought however that there was any evidence to support the view that cement chimney dust causes a direct danger to health. My hon. Friend the Member for Thurrock (Mr. Solley) who started this discussion tonight, suggested that there was a doubt, but there is no doubt whatever that cement chimney dust—which, let me make it plain, is not cement, but fine particles of clay and dust which come out of the kilns—does not have a direct effect on health. That does not mean that it is not annoying in a hundred and one ways, but I do not want to be alarmist about it.

We cannot be indifferent to the economic aspects of this question. The works in the region produce one-half of the cement made in Britain-4,500,000 tons a year. There is no comparable region in the world. By far the largest export of cement comes from this area. Therefore, it is not, so I am advised by my colleagues, possible to let up in production because of the terrific need we have for cement both at home and overseas.

May I now turn to the aspects of this question which concern my Department? The law relating to cement works says that the owner shall use all practicable means of preventing the escape of fumes, and these words have reference not only to the erection and maintenance of appliances but also to the proper supervision and use of them. Cement works have to be registered with my Ministry, but it is only since 1935 that such works were added to the schedule of the Alkali Acts, and since then new works have had to have the best appliances from the start, and existing works have had to provide such appliances. We have special inspectors in the Department concerned with all the works under the Alkali Orders, and they are in the closest touch with all the firms. In anticipation of the discussion tonight, I spent part of this morning talking about the question with them, and I hope in due course to go and see the whole thing for myself. I would have gone today, but in the time available it was not possible for me to get away.

I would like to say, in justice and fairness, that in our experience the managers of the cement undertakings in this area are willing to co-operate not only in the field where we have statutory control, the high-level emission of dust, but in the field of low-level emission of dust where we have no powers at all. I do not think that, in fact, from the time we had statutory powers, their record is open to very much criticism. After the cement works were put under this order in this area, that is, from 1935 to the outbreak of war, we got 18 electrical precipitation appliances in operation. In those days plants cost something like £30,000 or £40,000, and over that period, although things were not wholly satisfactory, there was considerable progress. But for the war we should, by the exercise of our powers, have got the Thames-side cement industry into the right position in relation to prevention plants. The war knocked that on the head, and there is a quite genuine difficulty at present in getting delivery of the plant.

I do not need to talk about the competing demands for steel for all the various purposes essential to our economic survival. I would not deny that it is easy for me departmentally to make an extremely good case for steel for certain purposes, including purposes of this kind and for electrical precipitation units, but the fact remains that when the allocation of steel is made, and all the other competing claims taken into consideration, then the allocation just does not permit, within the bulk allocations, anything but a quite small output of this type of plant.

Especially in the light of what I have heard tonight, I will certainly do all I can to push forward the production of precipitation plants, but I would not want to mislead anyone on that point, because the allocation of steel is so limited that what it might be open to me to do is also limited, and until we get an improvement in the steel position I am not very hopeful of our being able to do anything very rapid. I have a list of what is being done at present. Some of the plants in this area have, in fact, got precipitation plants in process of erection, others have plants being overhauled because they have got badly "out of trim" during the war, and others have got precipitation plants on order.

I can assure hon. Members that we shall, through our alkali inspectors, do what we can to get a move on here, but I would say that our major difficulties are in the supply of steel, and not difficulties at the present time on the part of any of the cement firms. Although our discussion has largely been concerned with the high-level emissions which cause widespread troubles, we have made considerable progress since the war in dealing with low-level emissions where the problem is localized in character, and where we are not held up in the same way by shortages of materials. There may be one or two points I have not dealt with, but I have taken note of all that has been said in this discussion, and shall take a further opportunity of going into the matter with my advisers.