§ 12.15 a.m.
§ Mr. Neil McBride (Swansea, East)The biological requirements to sustain life in the atmosphere, consisting mainly of nitrogen and oxygen, and in the water and soil to sustain plant life, are limited but constantly replenished by cyclical pressures, and so it is that anything emitted into and held to be injurious in the atmosphere, whether sporadic or of a recurring nature requires to be subjected to careful examination, and this is the reason for debating the, emission 203 of acidic gases from the Imperial Smelting Chemicals Plant at Llansamlet in my constituency.
As a result of receiving deputations from my constituents from the Llansamlet area I tabled a series of Questions on 24th April about the emission of sulphur dioxide from the Llansamlet plant. If sulphur dioxide is emitted, inevitably it is converted into sulphur trioxide by the atmosphere's humidity. This then leads to the formation of sulphuric acid vapour—or particles—and this is a highly potent corrosive acid, severely injurious to health.
Since October, 1971, there has been a series of emissions from this plant, occurring mainly during the night and at weekends. My constituents wish me to point out that within a radius of one mile from the plant there are several large schools—Trallwn Primary School, Cwm-glas Primary School, Cwm Primary School, Llansamlet Comprehensive and Infants School and Cefn Hengoed Comprehensive School, all with hundreds of pupils. They ask me to say that the time spent on making a survey there was infinitesimal.
Humidity in the atmosphere and wind direction are important when related to the emission of sulphur trioxide, and the serious point here for the Minister to consider is that there is no alkali inspector stationed in Swansea. This means that when a complaint is made an inspector is sent over from Cardiff, not immediately, but the next day, and these inevitably late visits add to the anger and anxiety felt about what my constituents declare is bad atmospheric pollution in the Llansamlet area. As they say, it causes damage to humans, animals, vegetation and, indeed, to buildings in the vicinity.
How many amendments have been made to the Alkali Act, 1906, in this regard? Paragraph 4 of a letter dated 4th May, a copy of which is in the possession of the Secretary of State for the Environment, says that the emission levels given by the Minister are not accurate. Dealing with the emission level figures for sulphur trioxide, the residents point out that during the time the plant was operating at 60 per cent. capacity 20 grains of sulphur trioxide were emitted on 27th April. They assert that 204 if the plant were operating at 100 per cent. capacity it would emit 3.3 grains of sulphur trioxide, and that is above the permitted level. The recorded levels are taken through the stack, but in view of the topographical nature of the terrain surrounding the plant, one is bound to ask whether the stack is high enough. In view of the high level of humidity, at times almost absolute in Llansamlet, my constituents feel that this could have a retaining effect on the gases emitted in this area.
Because the recorded flow is taken through the stack, this fails to take into account the leaks from the 370 tubes in each heat exchanger, so that two important points emerge. First, what are the corrosive properties of the metal used in the manufacture of the tubes, and, second, we have the question of plant maintenance. In the manufacture of sulphuric acid, with its high corrosive effect, provision should be made for research into metal pipe manufacture with the aim of producing pipes for these chemical processes which will have the highest possible anti-corrosive properties, and to begin with I would suggest looking into the possibility of using stainless steel.
There could be provision in the pipe system for a small straight length which could be withdrawn and a similar straight length inserted and withdrawn, cut in half-section to show the extent of the corrosion. This could be done some time prior to the end of the known life of the pipes that are currently being used. The chemical processes used in the manufacture of sulphuric acid could by this means be shown to exert a certain corrosive reaction on the pipes.
I am advised that there is no good reason why, given proper maintenance—this is vital—the manufacture of sulphuric acid should result in such a high level of emission of acidic gas or why such an emission need by tolerated. I am further advised that there is no scientific reason why, under proper control, emissions of acidic gas should not be eliminated entirely. However, all this presupposes good, efficient and constant maintenance services by plant owners.
The Minister will be aware that there have been complaints of vegetation being destroyed through acid burn, and the signs at the montage mountings clearly 205 confirm this conclusion. Professional opinion based on field study and chemistry reinforces this view, as the bleached condition of plants is indicative of the action of sulphur dioxide emission. Expert opinion—it is as a result of that opinion that I speak tonight; I refer to qualified graduate opinion to the standard of bachelor of chemistry and Ph.D. in chemistry—bears out this conclusion.
In a letter dated 9th May last the Secretary of State for Wales gave me figures of the emission of microgrammes per cubic metre, and those figures contrasted sharply with figures provided on page two of another letter from the right hon. Gentleman dated 4th May in connection with the incidence of respiratory diseases.
In this connection, it is interesting to consider the figures for pollution deposition provided by the Frederick Place Clinic. This clinic is situated one mile in direct line with the plant stack. The clinic pointed out that it is high on a hillside, tucked away round the bend of a hill, on the lee side and not on the windward side. The moist south and south-west winds which keep sulphur dioxide down and over Llansamlet do not blow towards this clinic. Therefore, the peaks of pollution are not recorded. Only the outside weakest fringes are recorded. The accuracy of the recording figures furnished to me in the letter of 9th May is therefore questionable. In the Llansamlet area there is a belief that one would require greater accuracy.
In the South Wales Evening Post of 27th April it is admitted that malfunctioning of certain equipment in the plant lasted for about six weeks, and apologies were tendered to local residents for any distress caused. But it is interesting to note that local house roofs, in some cases, required repair as a result of the erosion of the nails which affix the slates and tiles. One wonders who pays for the repairs. I have not been satisfied with the answer I received to a Question I put on that subject.
In a letter to me dated 9th May, the Secretary of State for Wales intimated that the head teachers of Cwm Junior School and Trallyn Infants School had noticed a tendency to respiratory irritation in damp or foggy weather. My constituents ask for better monitoring 206 arrangements and speedier inspection arrangements to ensure that sensible measures are undertaken. It is equally obvious that, with the rapid development of the chemical industry, perhaps the old legislative safeguards are insufficient, and it may be that new protective laws should be enacted. In this matter my constituents ask for no more than simple justice. Tonight I prosecute that claim. The right is certainly theirs and they deserve no less. With regard to the relationship with adults, I draw the Minister's attention to the letter of 4th May containing references to certain medical opinions.
Returning to the question of children, no child should be exposed to even the slightest risk of even mild respiratory irritation. I ask the Minister to ensure that medical safeguards are erected against respiratory infection of any nature caused by industrial processing. Clearly the malfunction of equipment was the reason for the emissions of sulphur trioxide which occurred. The Minister may feel that he has a duty to consider new legislation or amendment to existing legislation to prevent any instances of respiratory symptoms or chronic bronchial conditions in Llansamlet.
Therefore, I ask that a full, detailed and authoritative inquiry be instituted. What has gone before has not satisfied my constituents. They would like such an inquiry to be held, with the following factors as terms of reference. First, there is the question of bringing up to date the Alkali Act, 1906, and a consideration of the maximum levels of deposition permitted in areas of geographical and climatic difficulty such as Llansamlet. Second, there should be continuous recording of SO2 and SO3 levels on four sites chosen by Llansamlet residents, who would suggest the levels and the correct places. Third, a full maintenance programme should be instituted to avoid repetition of another breakdown causing emission and, therefore, anxiety. Finally, failing the appointment of an alkali inspector for the Swansea area, there should be an emergency system of contacting the Alkali Inspectorate in order that inspectors can assess conditions at a period of emission and not subsequent to that emission.
These are the things I ask for my constituents. I place the matter in objective fashion, shorn of any other consideration, before the Minister of State trusting that 207 he will accept all the requests which I make in that fashion.
§ 12.30 a.m.
§ The Minister of State, Welsh Office (Mr. David Gibson-Watt)The hon. Member for Swansea, East (Mr. McBride) is to be congratulated on choosing for the Adjournment debate a subject which is of such importance to his constituents. Had I a problem in my constituency which had caused anxieties such as the hon. Gentleman has described, I would have sought to do the same as the hon. Gentleman has done tonight. He has addressed the House on a highly scientific matter. I shall attempt to deal with the points he has raised. If I do not deal with all the points, I assure the hon. Gentleman that I shall be only too happy to talk to him, to exchange correspondence, or to look further into the matter, in an effort to help him to allay the anxieties of his constituents.
As the hon. Gentleman said, my right hon. Friend has written to him about the problems which have arisen due to emissions of sulphur dioxide from this works. It may be useful if I set out in detail how the problems have arisen and what steps are being taken to deal with them.
Imperial Smelting Chemicals Limited operates a contact sulphuric acid manufacturing plant in Swansea which has been subject to the provisions of the Alkali Act for over 10 years. The sulphuric acid is produced from sulphur dioxide gas. Before September, 1971, this gas was mainly obtained by smelting lead and zinc ores, but, following the closure of the lead and zinc processing part of the works at that time, the sulphuric acid plant was modified to incorporate the burning of elemental sulphur to produce sulphur dioxide.
The new process involves the conversion of sulphur dioxide gas into sulphur trioxide and the absorption of this gas in sulphuric acid to produce more acid. To ensure the most efficient conversion of the sulphur dioxide, the hot sulphur trioxide leaving the converter chambers is used in a series of heat exchangers to preheat the incoming sulphur dioxide. The residual gases are processed to remove acid gas, and acid mist, and then discharged to the atmosphere through a 120-ft. high chimney. In normal circum 208 stances, therefore, emissions of the gas to the air are kept to a bare minimum.
During the power shortage at the beginning of this year, however, certain items of plant had to be closed down. I am told that the closure of these units, coupled with the possible inefficient operation of some other items of plant, caused completely unexpected corrosion within the heat exchangers. The conversion process therefore became less efficient, and an increased amount of sulphur dioxide gas emerged to overload the exit gas removal plant.
This, especially during the period at the end of March and early in April this year, resulted in occasional emissions of higher gas concentrations than normal from the final exit chimney.
As my right hon. and learned Friend told the hon. Member, the alkali inspector, who received several complaints about the emissions, went to the factory at the end of March and on his advice immediate steps were taken at the works to reduce emissions by some 30 per cent. The plant was again operating to his satisfaction by mid-April.
The company at that time brought in a special technical team and, once the problem had been identified, put in hand the necessary work to rectify the situation.
The plant has operated since the end of March with two of the six production units out of commission, and since then three units have been rebuilt. It is necessary to run the plant in order to carry out investigations, but tighter control of all parts of the process is now being exercised.
I might add that all this has been done with the approval of the alkali Inspector, and that the company's estimated costs for remedial work done and required amount to over £34,000.
This, then, is the situation at the plant. The hon. Member has rightly emphasised the adverse effects which these emissions could have had on the health of those living in the vicinity of the works. As he knows, the Medical Officer of Health for Swansea County Borough Council was asked by my right hon. and learned Friend to carry out an investigation, and the first results of this investigation, were passed on to the hon. Member in my right hon. and learned Friend's letter of 209 9th May. A copy of the report has also been placed in the Library of the House.
At that stage the borough's school medical officers had visited seven schools in the vicinity of the works. At two of these the head teachers reported that in some foggy or damp weather conditions in recent months they had noticed a tendency towards respiratory irritation amongst some of the children. No children, however, were presented to the borough's medical officers as continuing to suffer irritation. At the remaining five schools the head teachers reported that there were no relevant health problems.
The borough medical officer of health also made enquiries with general practitioners whose practices are in the vicinity of the works. They reported that there had been no complaints of ill health arising from the emissions from the Swansea Vale works and that there had been no increase in recent months in cases of coughs and tonsillitis. The medical officer of health has since extended his inquiries and has contacted four other general practices in the area. Three had noticed no increase in morbidity during the relevant period. One had noticed an increase in "eye irritation", but on further investigation the cases referred to were found to have occasioned in Morris-ton, and the general practitioner concerned did not think they were connected with the Llansamlet incident.
The local authority takes daily average readings of sulphur dioxide levels in the atmosphere in the neighbourhood of the works. These showed that during the period 21st March to 10th April, excluding the holiday period, the 24-hour sulphur dioxide average ranged between 271 and 464 microgrammes per cubic metre. On 11th April, a 24-hour average of 584 was recorded, but following that date reported averages were mostly between the range of 60 and 90 microgrammes per cubic metre.
The effect of the steps which have been taken to reduce emissions from the plant is therefore clearly to be seen. Advice from the Medical Research Council is that, on present evidence, no harm should be sustained by man if the daily average of sulphur dioxide in the atmosphere is below 500 microgrammes per cubic metre, on any day, combined with roughly 250 microgrammes per 210 cubic metre of smoke. Our knowledge of the medical effects so far, therefore, is that the unusually high emissions of sulphur dioxide from the plant over recent months gave rise to some cases of respiratory irritation amongst school children in the area, but there would appear to have been no lasting effects from this. Continuing discussions are being held with local authorities, however, about the possible need for further investigations in the area.
Among other things, the local authority is considering the introduction of more complex equipment to monitor levels of sulphur dioxide on a more detailed basis to show peaks as well as daily averages They are also to look into the monitoring of sulphuric acid.
On the effects of the emissions on vegetation in the area, the alkali inspector received complaints about damage to plant life in the vicinity of the works, and reported this to the Chief Public Health Inspector for Swansea County Borough Council. The Chief Public Health Inspector sought assistance from the Agricultural Development and Advisory Service of the Ministry of Agriculture, Fisheries and Food. A detailed investigation of the situation could not be undertaken by the service except at the request of farmers in the area, from whom no complaints have so far been received. The advice we have received from the service on an informal basis, is that high emissions of sulphur dioxide such as those which took place during the period from the end of March to the beginning of April could have caused short-term damage to plants by affecting foliage. A number of other factors—the quality of the soil, the presence of other pollutants in the atmosphere, and general climatic conditions—would also have affected the damage caused, but recovery from damage caused by intermittent high emissions of sulphur dioxide would take place within a growing season.
Long-term, serious damage to vegetation would be caused only by continuous high emissions of the gas over a very long period. This advice has been largely corroborated by a report which we have received from the company. Its Environmental Control Officer has investigated complaints, and is examining specimens of damaged plants.
211 He has not yet established whether damage was caused by sulphur dioxide emissions, soil conditions, general industrial surroundings or a combination of all three; but we must bear in mind that the natural vegetation of the valley has been modified by decades of industrial pollution, so that most native plants have developed a considerable degree of resistance to atmospheric pollutants. It is significant that newly-established tree plantations, mostly conifers, have been found to be perfectly healthy at a distance of half a mile from the works.
I think it is relevant at this point to mention the fact that the Welsh Office is currently sponsoring a multi-disciplinary study of the levels of heavy metal pollution in the atmosphere of Swansea, Neath and Port Talbot, which I announced not many months ago.
This study, which will also survey levels and possible effect of heavy metals in human beings, animals and vegetable life, should throw considerable light on the general position regarding air pollution.
To summarise, I am satisfied that the company has taken and is taking the 212 necessary steps to reduce emissions of sulphur dioxide to the atmosphere to a level considered satisfactory by the Alkali Inspectorate, and that these emissions are certainly well below the levels which would constitute a danger to health. It is also worth emphasising that acidity tests on emissions from the process art the plant before and after the complaint period were satisfactory. Investigations into the problems at this plant and into other problems of pollution in the area are continuing in conjunction with the local authority, and I will keep the hon. Member informed of subsequent developments.
If the hon. Member finds on reading my speech in the OFFICIAL REPORT that I have not dealt adequately with any points, I will be more than happy to meet him and talk about them with him, because this is a matter of concern to him and his constituents and the Welsh Office wishes to take all possible steps to put their fears at rest.
§ Question put and agreed to.
§ Adjourned accordingly at eighteen minutes to One o'clock.