Published weekly by the Department of Health, City of New York, 505 Pearl St., New York, N. Y. Entered as Second-Class matter October 16, 1917, at the Postoffice at New York, N. Y. Under Act of March 3, 1879. Subscription, 10 cents per annum.

ROYAL S. COPELAND, M. D., Commissioner of Health.

NEW SERIES, Vol. XI.

JUNE 24, 1922.

No. 25.

DANGERS FROM ILLUMINATING GAS.

As a consequence of an increased number of deaths from illuminating gas poisoning and the advertisement of a gas company in a city newspaper recommending that gas water-heaters be connected to a flue, the Division of Industrial Hygiene of the Department undertook an investigation of the questions involved.

As a preliminary, at the direction of the Deputy Commissioner, the Sanitary Expert of the Department, Dr. Joseph A. Shears, prepared a special report upon the question, which is given below:

To the Deputy Commissioner:-I have the honor to submit for your information the following report on combustion of illuminating gas. I have taken this matter up in detail so that the subject can be viewed from each and every angle. Perfect combustion of illuminating gas has a highly beneficial effect on the quality of air. It has been assumed that because of the burning of gas, and the discharge of products of combustion into a room a vitiation of the atmosphere must result. The combustion of illuminating gas produces, from a chemical standpoint, four different effects upon the air taken from a room, mixed with the gas in the burner and discharged back into the room.

First: The amount of oxygen is reduced.

Second: The amount of carbon-dioxide is increased.

Third: A very small amount of sulphur-dioxide is added.

Fourth Dust and bacteria are removed by incineration.

The first, second and third effects are caused by oxygen combining with the carbon and sulphur maintained in the gas and this oxidizing process generates heat which is sufficient to produce the fourth effect. The physical effects produced upon the air are increased temperature, circulation of the air in the room is accelerated and ventilation from the outside is increased.

As the quality of the air in the room at any time depends upon the interaction of the incoming air upon the products of combustion discharged from the burners and the organic matter exhaled from the lungs and skin of the occupants of the room, it is necessary to investigate the inter-effects of all three. On account of the tendency of heated air to expand, become lighter and rise, the presence of any source of heat in a room produces a certain circulation of the air, which serves a double purpose. In the first place, the heated air is cooled by contact with succes

sive portions of the relatively cool walls, and in the second place the temperature in the upper portions of the room tends to increase, while that in the lower portion tends to decrease below that which would prevail without circulation. This produces an unbalanced pressure from the outside, tending to draw fresh air in at the bottom of the room through crevices, joints and other openings, and also to a greater extent than is ordinarily realized through the walls themselves. The same action tends to expel the air in the upper portion of the room in the same manner, and this tendency is, of course, greatly augmented by increased facilities for ventilation.

In considering the concurrent effects of heat sources and the incoming air upon the average quality of the interior air at any moment, it is necessary to inquire into the nature and effects of the vitiating substances. Generally speaking, these are divided into two classes: Those emitted by the respiration, both from the lungs and the skin of the people in the room; second, those emitted by the illuminants. The first class includes bacteria of those diseases which are transmitted by bacteria which, when taken from the air into the system through the mouth or skin, will produce their characteristic diseases. As a matter of fact, the supposedly fresh air from the exterior is often heavily laden with bacteria of this character.

More commonly than any other are felt the effects of the vitiation produced by the organic matter, in a greater or less advanced stage of decay, exhaled by the lungs. This produces the stuffiness in a poorly ventilated room which is sometimes ignorantly attributed to carbonic acid gas.

Carbonic acid gas is present in the purest of outdoor air in the proportion of about four parts in 10,000 and produces no discomfort or ill effects if less than 225 parts in 10,000 of air are present. On account of the ability of gases to diffuse through even the tightest walls used in building construction, the proportion of carbonic acid gas in interiors rarely rises above 20 parts in 10,000, through for experimental purposes this proportion has been made as high as 50 parts in 10,000. This was accomplished only by resorting to exceptional means to secure a high percentage of this gas. Thus, practically speaking, it may be said that it is impossible in practice to obtain enough carbonic acid gas in an ordinary room to produce the slightest effect upon the bodily functions, even when the most sensitive tests are employed to detect such effects.

Sulphurous acid gas when present is in such almost infinitesimal quantities that it is disregarded as far as the effects on health are concerned. While it is, in the quantities found, harmless to the human organism, it has a decided sterilizing effect as regards disease germs.

While it is true that carbonic acid gas artificially produced-that is, by gas combustion is entirely inocuous in any quantity met with in human habitations, it must not be assumed that such quantities of this gas exhaled from the lungs, may be regarded as an indication of sanitary conditions. On the contrary, even 15 parts of carbonic acid gas in 10,000, if arising from respiration of human beings, indicates the presence of organic matter in such quantities as to be highly obnoxious or even harmful.

In this connection it should be noted that the vitiation of air by human beings is generally expressed as percentage of carbonic acid gas, because it indicates the amount of organic matter which has been given off in the same period, and while the latter (which is a real source of pollution) is difficult to measure, the carbonic acid gas is easily determined.

From a sanitary standpoint, therefore, figures regarding the quantities in which carbonic acid gas indicates harmful conditions apply only to this gas when thrown off by the lungs and not to the same gas produced by artificial means.

It is evident that the practice of rating each gas burner as equal to a certain

number of human beings in vitiating the air in interiors is opposite to the dictates of

common sense.

Investigators on the effects of carbon-dioxide report as follows:

Dr. Angus Smith shut himself in an airtight chamber with a lighted candle, and remained until the candle was extinguished by the high carbon-dioxide content produced (229 parts in 10,000). He felt no ill effects.

Dr. Richardson removed all the carbon-dioxide from air that had once been breathed, and found that animals introduced into such air dwindled away rapidly and died.

Pettenkoffer found that 100 parts of carbon-monoxide in 10,000 parts of air was not injurious to human beings, while one-tenth the amount of carbon-dioxide derived from lungs and skin exhalations rendered the air unfit for human habitation for any length of time.

Proof of a similar nature from the experiments of recognized authorities might be multiplied almost indefinitely.

Another feature of even greater importance is the effect upon the eye. Rideal's tests showed that:

Dr.

(a) The sensitiveness of the eye to light as measured in the perception test diminished very markedly after exposure to the electric light, while no corresponding effect is noticeable after the eye has been subjected to gas light.

(b) The power of co-ordinating and using the motor muscles of the eyeball recorded in the orbicular muscle-tests was diminished to a greater extent after subjection to electric than to gas light.

(c) It was found that the ciliary muscles of the eyes are more accommodative after three hours' exposure to the 50 c. p. light from the Darwin incandescent mantle than after a similar exposure to a 50 c. p. electric ilght.

(d) The acuity of vision measured by the retinal test again shows that the optic nerve or center was more susceptible in the case of gas illumination. It will be seen that all the results point strongly in the same direction-namely, that gas light as used in these experiments is less fatiguing to the eye than electric light.

Nearly all of the fatal cases of gas poisoning are due to carelessness, or are deliberate, with suicidal intent.

Accidental causes of gas poisoning may be classified as follows:

1. Filthy burners.

2. Flare back in bunsen burners.

3. Turning flame low enough to be extinguished by gust of air.

4. Pilot light out, gas turned on.

5. Defective tubing.

6. A-Turn on gas; B-turn out; C-on again-these are extremely dangerous conditions, any one of which give rise to large volumes of carbon-monoxide. In all causes of death due to gas poisoning it will be noted that one of these six conditions was the cause of death.

It is suggested that

Recommendations.

(1) No hot water heaters be permitted in bath or other confined rooms unless same are flue connected.

(2) All automatic hot water heaters be flue connected.

In other conditions flue connections should not be made, whenever it can be avoided, as there is a danger of back draft.

The question of flue connecting is, at present, the subject of an investigation by the American Gas Association, and their findings and recommendations will be ready soon. It is respectfully recommended that no action be taken by this Department until the recommendations are noted.

Your attention is called to the action of the Board of Aldermen, December 14, 1020. The matter of gas tubing was referred to the Commissioner of Health for action. The Department has made an intensive study of gas tubing and submitted a report: "Standard Performance Specifications for Flexible Gas Tubing."

May 2, 1922.

JOSEPH A. SHEARS, M. D.,
Sanitary Expert.

PHYSIOLOGICAL EFFECTS OF EXPOSURE TO LOW CONCENTRATIONS OF CARBON MONOXIDE.

"The effect of comparatively low concentrations of carbon monoxide for short periods and under normal air conditions of temperature and humidity, with the subject at rest, was studied by Dr. Yandell Henderson and his co-workers. In making recommendations to the New York and New Jersey Tunnel Commissions,* Dr. Henderson advised that if the Hudson River vehicular tunnel be so ventilated that persons passing through the tunnel would be exposed to not more than 4 parts of carbon monoxide in 10,000 parts of air for not longer than 45 minutes, they would experience no ill effects. This advice has been confirmed in supplementary experiments carried out by us in connection with studies at the Bureau of Mines Experiment Station at Pittsburgh.

"In continuing our studies on low concentrations of carbon monoxide, we made a few experiments in a gas chamber where the conditions could be accurately controlled. The following is a summary of the findings:

SUMMARY OF PHYSIOLOGICAL EFFECTS OF LOW CONCENTRATIONS OF CARBON MONOXIDE UNDER VARYING CONDITIONS.

With the subject at rest.

"1. The exposure for 6 hours to 2 parts of CO in 10,000 of air caused

a. Saturation of 16 to 20 per cent of the hemoglobin of the blood with CO.

b. Very mild subjective symptoms of CO poisoning at the end of the test.

c. No noticeable effects after the test.

"2. The exposure to 3 parts of CO caused

a.

Saturation of 22 to 24 per cent of the hemoglobin with CO after 4 hours, and 26 to 27 per cent after 5 hours.

b. Symptoms at the end of 2 hours absent; after 4 hours, mild effects attributed to CO poisoning; and after 5 hours, moderate effects.

c. After effects of 4 hours' exposure, mild; of 5 hours' exposure, moderate.

"3. The exposure to 4 parts of CO in 10,000 caused—

a. Saturation of 15 to 19 per cent of the hemoglobin with CO at the end of 1 hour, and 21 to 28 per cent at the end of 2 hours.

b. After effects, moderate to marked.

With the subject exercising strenuously.

"1. The exposure for 1 hour to 21⁄2 parts of CO in 10,000 caused

a. Saturation of 14 to 16 per cent of the hemoglobin with CO.

b. Moderate symptoms of CO poisoning at the end of the test.

c. After effects mild to moderate.

"2. The exposure for 1 hour to 3.3 parts of CO in 10,000 caused

a. Saturation of 17 per cent of the hemoglobin with CO.

b. Mild to moderate symptoms of CO poisoning.

c. After effects mild to moderate.

*Report of Tunnel Gas Investigations (Problem 2: Physiological Effect of Automobile Exhaust Gases) made by Yandell Henderson, H. W. Haggard, M. C. Teague, A. L. Prince, and Ruth Wunderlich, published by the New York and New Jersey Tunnel Commissions, 1921.