fact sheet was really a very limited bill of particulars and our discussions were quite informal for some time. But, because there arose an immediate polarization on this matter, we felt a community responsibility, as experienced engineers, to try to develop something that would approximate a complete rationale of the whole matter. In that way, we were trying to do the job that the Governor of Wisconsin's task force is now setting out to do. We made some attempts to have the metropolitan planning commission make such investigations but we were not able to conduct this, at least, successfully.

We would also like to emphasize that the problems that are elucidated by this situation are going to be intensified. As Mr. Ewald testified yesterday, there is an increasing need for electric power that no one can deny or wants to deny. So if we visualize problems at this state of the game, imagine what they will be when they are twice this in 10 years and four times this in 20 years.

As we proceeded in the study, there were four things that came out, and I will comment briefly on them because we have commented in detail in the written report:

One was the quantity of sulfur dioxide, commonly known as SO, is really large. Frankly, I am disappointed that, in the early fact sheets, there was no reference whatsoever to the fact that a poisonous. effluent like SO2 was going to be coming from this plant. There were, indeed, electrostatic precipitators that would remove dust and I certainly commend the company for that move. The quantity of sulfur dioxide is based on a very high sulfur content of this coal. It is 3.4 percent of that combined with the fact there will be a very large amount burned. Approximately 1,700,000 tons per unit will produce 100,000 tons of SO2 in our area per unit per year. To get some perspective of this, we did a little looking around, and I would like to make a modification, if you please, in the official notes. There was a typing omission. The first line should read, "The expected 200,000 tons," and here is the insertion, "is about 10 percent of the amount of total gaseous pollution released in the entire Greater Chicago area." This reference is to an article that appeared in a magazine. And another astonishing thing: This will be almost 1 percent of the total sulfur dioxide in the United States from all causes-not just powerplants. So I believe it can be seen the quantity of material here is very great.

Another comparative figure is that in a survey made by the department of health in 1957, I believe, it was discovered that there was an estimated effluent of 31,000 tons of sulfur dioxide in the whole Twin City area compared with 200,000 from this single plant to the 31,000 in the total Twin City area a few years back.

I would also like to call your attention to the fact that comparisons to this plant and the plants in St. Paul are not accurate unless they include the consideration that the plants from St. Paul are powered by interruptible natural gas; which is, a low sulfur-containing fuel. The low sulfur-containing fuel is used in the summertime when the problem, as I will show you later, would be most aggravated so thatfrom figures we got from Northern States Power Co. that they burned last year 1.3 million tons of coal for one and a half million kilowattsand pardon the numbers-you can estimate that three quarters of the total energy derived from the Twin Cities plant is from natural

I understand from listening to Mr. Ewald, and I also understand from the Federal Power Commission, that there are problems in using natural gas on a noninterruptible basis. I am sure this is not an easy problem and I, certainly, don't want anyone to think that we think it is.

The second consideration that I would like to direct your attention to is that the question now is whether any of this huge quantity of gas comes down to the ground, and then I would like to cover, if it comes down to the ground, does it cause damage? Now, this was a rather difficult problem to tackle because there was a general absence of data but, by shear luck, we discovered that data has been taken and, to my knowledge, this is the first time it has been introduced by anyone into this consideration. Data has been taken for a number of years on the KSTP tower in St. Paul. This tower is over 500 feet high and its elevation, at its foot, is about 250 feet higher so we have an elevation of almost 700. The purpose of these measurements all the way up the KSTP tower, as a matter of fact, is to measure macroinversion. The macroinversions are the meteorological phenomena that could really give us a problem with this plant, in our view, and I think this is sustained in the literature as you read it.

The microinversions, which we see very frequently, will probably be confined to the height of the bank or, perhaps, a hundred feet over that and, of course, the high stacks will greatly relieve any problems derived from those. Of course, in the early days of SO2 effluent, it was dumped out at treetop level and everybody knows what particular damage was done, particularly in your State, Senator, from sulfur dioxide.

I would like to comment on these. These were taken in 1962. They were for a whole year and they were presented as a report of progress at the American Industrial Hygiene Association's annual meeting in Philadelphia, Pa., May 1964.

Senator NELSON. May I interrupt to ask, Who was taking the data? Mr. HUMPHRIES. A professor at the University of Minnesota who has told me that he would be very glad to verify the data but, he also emphasized, that he is a personal friend of some of the people at NSP and cannot be involved in this matter as a partisan but he would be very glad to authenticate the data and warrant that it is true and present the original.

Senator NELSON. I take it he wasn't gathering data for purposes of this hearing?

Mr. HUMPHRIES. That is correct, sir. He was gathering this data for the purpose of research at the University of Minnesota.

So it was fortunate that we stumbled across the data-rather we found it in our searches. We searched far and wide for this data to show the occurrences of microinversions to a height of approximately 800 feet. It is the view of those people that took it that these inversions must have frequently occurred at much higher altitudes, perhaps at 4,000 to 5,000 feet, althought the data will not show this. If you will notice, there are 164 incidences or a number of inversions during the year and the very significant thing is the high number in July, August, September, and October. Now, I know that people at Stillwater are mad at me but I want them to know that this data shows that, during those summer months, they are going to be in real danger from sulfur

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dioxide pollution of their city and, particularly, those who live up near the golf course because, during those summer months, the prevailing winds, as shown by wind erosions that are published by a number of sources-I have this one in my hand from the Metropolitan Planning Commission. During the summer months, the prevailing winds are from the southeast and 3 percent of the time their velocity is lower than 8 miles per hour. Now, I am given to understand that at this time of low wind velocity and temperature inversion where there is, in a sense, a lid on the atmosphere preventing just the wholesale dispersion of this material and definitely limiting it like a container that had definite size, this is the situation which will provide the hazard, and it definitely occurs, and it occurs a great deal of the time during the summer months. I think this puts the real finger of suspicion on a full coalburning plant on this site.

Now, my last point is that to say the least, as was gone into yesterday and as gone into by written disclosure here, the laws in Minnesota and Wisconsin, perhaps the United States, governing air pollution are inadequate. I believe that we can say in Minnesota that they are nonexistent. There are no standards although the department of health was given authority to prepare such standards. As was testified yesterday, it was made difficult to prepare such standards because the standards would have to take into consideration proof that such concentrations cause damage.

I would like to call your attention to the fact that there is a great deal of difference of opinion between authorities on what causes damage on sulfur dioxide and sulfur trioxide, which is also produced to the extent of 1 to 5 percent of the total emission, in people. Industrial standards are set in the 5 to 10 parts per million level, but there is increasing suspicion that very much lower concentrations, threetenths of a part per million, five-tenths of a part per million, which occurs occasionally, continuously, could cause great damage to people who have respiratory ailments, any cardiac problems, and just have grown old.

Now, Mr. Leland specifically asked me to submit a letter for him to the record. The only point I would like to mention in this, that Mr. Leland says that he signed the petition in Stillwater welcoming NSP to the valley. However, he does now feel that a plant of this size must not burn coal and contaminate the property, the lungs and eyes of our people with SO2. There is no tax benefit, no financial windfall in our area that could justify endangering the health and lifespan of our people. I would like to submit this for the record.

(The letter is as follows:)

Mr. C. RAYMOND HUMPHRIES,
Stillwater, Minn.

BAYPORT, MINN., December 9, 1964.

DEAR RAY: I have analyzed the data obtained by other technical specialists of the group of six engineers and scientists that have recently studied the air pollution problem that would be created in the St. Croix Valley by the operation of the Northern States Power Co.'s proposed plant at Oak Park Heights on the St. Croix River. After obtaining recent information from NSP with respect to the quantities of coal to be burned and NSP's own estimates of the tremendous quantities of sulfur dioxide that would be dumped into the air above the plant, I am forced to agree, albeit with reluctance that great hazards are present in the system of operation now planned by NSP.

The reluctance of which I speak is genuine. I can fully appreciate the anticipation of the people in all forms of commerce in the valley that this plant provides a sudden spurt to the economy of this edge of Washington County, and as a full-time, enthusiastic resident of the St. Croix Valley I have anticipated the potential tax relief offered by this new industry with pleasure. In fact, before analyzing the air pollution problem, I signed the petition in Stillwater welcoming NSP to our valley, and have consistently avoided any association with the Save the St. Croix until my own investigation had reached its conclusion.

At this time I am now ready to go on record, as a registered professional engineer, as being decidedly opposed to the establishment of a coal-burning powerplant in the St. Croix Valley. I feel that a plant of the size that is planned by NSP must not burn coal and contaminate our property and the lungs and eyes of our people with SO, and sulfuric acid. There is no tax benefit, no sudden spurt to the economy, no financial windfall to our area that could justify endangering the health and lifespan of our people. A method must be found, before this plant is activated, to remove the SO2 from the exhaust products issuing from the smokestack(s), or else natural gas should be burned or one or more nuclear plants should be designed to provide the necessary power.

Please add these comments to those of the other participants in these studies, with the hope that the residents of Washington County may be helped before it is too late, and that the Northern States Power Co. may be encouraged to consider other than strictly coal-consuming methods of producing heat to power electrical generators. Surely, when the lives and health of the residents of the St. Croix Valley might be endangered by the establishment of the presently planned coal-burning plant, a utility company with NSP's broad scope should be willing to consider systems other than the one currently selected in spite of the fact that the presently planned plant system probably is the rockbottom cheapest way for electric power to be generated in this area of the United States. PAUL M. LELAND.

Mr. HUMPHRIES. The last point relates to the level of the banks of the St. Croix Valley which creates a special problem here. As you will note in my notes, the department of health commented specifically that Bayport and Stillwater were in sites which were not generally suitable for dispersion of pollutants. This was put into a report almost 6 years ago.

Mr. Mertes drew this chart and I would prefer he make the comments on it and I wish to thank you gentlemen for the opportunity to appear.

Senator NELSON. Thank you. [Applause.]

Did you have any questions, Senator Metcalf?
Senator METCALF. No questions.

Senator NELSON. Thank you very much.

STATEMENT BY C. R. HUMPHRIES ON AIR POLLUTION

A proposal to build a large, soft-coal-burning thermal electric generating plant on Lake St. Croix at a site in Oak Park Heights has been made. Although the eventual size has been disclosed as exceeding a million-kilowatt capacity, requests to the U.S. Army Engineers, the Minnesota Water Pollution Control Commission and Minnesota Conservation Department have been related to the first unit of 500.000 kilowatts only.

This report will deal with the air pollution which will be brought about by this plant and the problems we think will result from it.

We would like to make four principal points:

1. The quantity of the principal pollutant, sulfurdioxide, will be huge. 2. The valley site and atmospheric conditions of the area lead to the possibility of frequent ground-level concentrations of dangerous proportions. 3. The price paid for the economic benefits could be corrosion of materials, damage to vegetation, and, worst of all, damage to human health.

4. Present laws appear to be wholly inadequate to prevent serious air pollution.

Point 1

One million seven hundred thousand tons per year of soft coal containing 3.4 percent sulfur has been given by NSP as the quantity they will burn for the first unit. This will produce at least 100,000 tons of sulfur dioxide per year. A second coal-burning unit could double that to 200,000. These figures contrast with the 31,000 tons of sulfur dioxide emitted over Minneapolis-St. Paul and suburban area in 1956 (Stanford Research Institute survey). NSP burns both natural gas and coal in its present plants located in the Twin Cities. Natural gas is a very low sulfur-containing fuel. The natural gas is on an interruptable basis. Present NSP coal consumption for these three plants totaling 1,500,000kilowatt capacity is 1,300,000 tons per year. Therefore from the data given by NSP for the St. Croix plant, it may be estimated that three-fourths of the energy produced in the present units is from natural gas. Therefore comparisons of air pollution problems of NSP's St. Paul-Minneapolis plants and the proposed St. Croix unit are not valid.

The expected 200,000 tons of SO. is approximately 10 percent of the total gaseous pollutants released in the entire Greater Chicago area (Bregman, I.I.T. Research Institute magazine Frontier, spring 1954, p. 11), and almost 1 percent of the total U.S. output of sulfurdioxide from all causes (1963 Report of Department of Health, Education, and Welfare, "Troubled Air,” p. 11).

Discussion of the complex chemistry of sulfur dioxide and its great hazard to health and property would seem redundant at this time, as it has been singled out by the Clean Air Act, Public Law 88-206, as one of the major unsolved problems in air pollution. It is the object of a great deal of research directed to eliminating it altogether as an effluent by extraction processes. This will cost money, and if the market for possible byproducts like sulfuric acid cannot absorb the additional costs ("Sulfur-Smoke Removal System," Public Service magazine, September 1964, p. 16), this could shade the overall economics in favor of atomic powerplants, six of which are already under construction in areas where air pollution is already a serious problem.

The pollution of the air in the St. Croix Valley and the surrounding territory a mere 5 to 10 years before the full solution to the sulfur dioxide problem would seem to be an unnecessary sacrifice, if alternate solutions or alternate sites for this plant are possible. We think there are such solutions and such sites. Point 2. Ground-level pollution

The use of the very high stacks, 700 to 800 feet, disclosed in public releases by NSP, makes it clear that they intend to rely on dispersion methods to try to eliminate the hazards arising from the large volume of sulfur gases released. It is almost certain that low-altitude release of these hugh quantities of SO would cause visible vegetative devastation and noticeable human problems so tragically evident in low-altitude releases of large quantities of sulfur dioxide in the past.

A basic question at issue is whether a clear and present danger from the huge volumes of gas is eliminated or has it been reduced? Examination of the literature on this score discloses that tall stacks may not be successful in serving their purpose (staff report, Committee on Public Works, U.S. Senate, September 1963, and Louis McCabe, "Air Pollution"). It is reported that tall stacks, even as high as 700 feet, can contribute little in dealing with conditions where available volume of diluting air is simply insufficient to satisfy the need of satisfactory dispersion.

The local conditions of vertical and horizontal air movements are strongly influential, as are also the changes of air temperature with pressure (adiabatic lapse rate. In well-mixed air the dry adiabatic lapse rate is 5.4° F. per 1,000 feet. When this condition exists, a plume will rise directly into the atmosphere until it reaches air of similar density (W. L. Faith, "Air Pollution Control," p. 32). If the air temperature increases with height, a condition of temperature inversion exists. Under these conditions the atmosphere is said to be stable, and very little mixing takes place. That is, the pollutants do not disperse. A "lid" is placed over the available atmospheric dump, permitting the development of very high concentrations in the atmosphere over the source of effluent. The tragic results in New York City, Donora, Pa., and London, England, occur when the "lid" stays on for extended periods, and neither horizontal nor vertical air currents are present to carry away the noxious effluents. These relatively rare extreme occurrences are not the only hazards. Temperature inversion lasting even several hours can contribute to the direction of "slugs" of the highly concentrated stack gases coming to the ground before adequate dilution to minimize