654	THE COLLIERY GUARDIAN.

________________________________________________________________________________

April 7, 1916.

tice. Air which contains enough, nitrous fumes to cause
feelings of irritation in the nose or air passages is very
dangerous.

The;, symptoms of poisoning are very characteristic.
At the moment of exposure they are slight. A man who
inhales nitrous fumes has a sense of irritation in the nose
and throat, and of constriction, and perhaps pain, in the
chest. There is headache,'smarting of the eyes, and
there is coughing. The latter is a characteristic sign.
But these immediate irritant effects may not be severe,
and commonly pass off altogether in a short time. The
man may feel quite well, and may continue to work.
He leaves the mine, has his supper perhaps, and goes to
his room. Then, in from perhaps four to eight hours
afterwards (very rarely later), acute symptoms suddenly
come on, and progress with alarming rapidity. In a
typical severe case there is marked and increasing dis-
tress in breathing, with coughing, and often severe pain
in the' chest. The cough is at first dry, and ausculta-
tion may at this stage reveal no moist sounds. But this
condition is speedily followed by the expectoration of a
copious frothy rather fluid blood-stained spit. The lungs
become waterlogged, and auscultation now reveals
copious moist sounds. There is cyanosis and marked
dyspnoea and distress, followed, unless the case is
promptly treated, and very often in spite of all treat-
ment, by collapse, unconsciousness, and death within
a few. hours. It is probable,' I think, that a certain
number of cases,. returned as “pneumonia,” amongst
underground workers, are really cases of nitrous fumes
poisoning.

Nitrous fumes never, in our experience of ordinary
gassing accidents, produce partial or complete uncon-
sciousness at the time of exposure, as does carbon
monoxide, although they may do so if present in massive
amounts, and cases of rapid death from the concen-
trated fumes of burning explosives may be partly due
to this cause.

The intensely irritating character of nitrous fumes
has suggested that ■ the repeated inhalation of small
quantities of this gas may, by maintaining a catarrhal
condition of the air passages and lungs, be a contribu-
tory factor in the development of miners’ phthisis.

Relation of the Circumstances of the Accident to the Type
of Poisoning Produced.

The two types of gas poisoning described are quite dis-
tinct, and the circumstances under which they occur
differ also in some respects. ■ Some years ago I made an
enquiry, in order to determine the relation existing
between the particular circumstances of these accidents
and the particular type of gas poisoning produced. By

the courtesy.of the Government Mining Engineer, I was

enabled to read through the reports by the mining
inspectors of all fatal gassing ..accidents which had

occurred on the Rand during the four years 1904-1907.
There were in all 64 accidents and 169 fatalities, so that

Table, A.—Fatal, Accidents from the Fumes of Explosives on the Mines of the Witwatersrand, 1904-1907.

Fatal Accidents.

(A) Due to Exposure to Fumes after blasting.

		Fatali- ties.							Predou inant type of gas poisoning.							
Character of accident.	02  'S <D  ’o				Locality.				(1) Carbon monoxide.			. .(2) Nitrous fumes.			(3) Indefi- nite.	
	Number of ac	White?.	.j	I Natives or I  1 coolies.	| Stope.	I Drive or  1 level.	| Winze.	| Raise.	i Shaft or i station.	| Instances.	Fatally i gassed.	Temporarily gassed.	|' Instances..	i Fatally gassed.	Temporarily gassed.	Fatally injured or gassed.	Temporarily injured or gassed.
(a) Exposure immediately or shortly after blasting- ... ... ..;..	  ■ ,(b) Exposure several hours (two or more) \ ' after blasting 	. :				19  28	5  5	21  34	1  1	11  3	21	2'  3	3	7  27	9  38	7  47	12 none	17.	16	1	
Totals 							47	10	55	2	14	23	5	3	34	47	54	12	17 j	16	1	

(B) Due to the Ignition of Explosives.

(a)	Explosives ignited, then exploded ...  (b)	Explosives ignited, no explosion 		2  15	7  7	55  35	3	6	1	1	2  4	p  2	p  16	p	1  14	1  26	9	61	15
Totals ............		17	14  24	90  145	3	6	1	1	6	3	16	—	15	27	9	61	15
Grand total all causes 	:				64	^169^		—	—	—	—	—	37	63	54 ;  ' !	27	44	25	62i	15 ;

the material was considerable. The results are shown in
the accompanying table reprinted (with slight altera-
tions) from the “ Statement on Conditions,Affecting the
Health of Underground Workers on the Mines of the
Witwatersrand,” originally submitted by Dr. Macaulay
and myself to the Mining Regulations Commission in
May 1908.

■ The accidents under review fall into two groups :—(a)
Those due to exposure to the fumes of explosives after
blasting, the ordinary “ gassing ” accidents; (b) those
due to explosives being accidentally set on fire and
burned.

fa) Accidents Caused by the Fumes of Explosives
After Blasting.—I found it desirable to subdivide this
group into two classes :—:

(1) The first class comprised those cases where the
exposure was immediately or shortly after blasting.
These accidents occurred when persons returned too
soon to the working places after blasting, or
when they were affected by the fumes of explo-
sives arising from blasting taking place in other
parts of the workings. The majority occurred in
drives. I found that in such cases either carbon
monoxide or nitrous fumes poisoning might result, but
that the’ latter type was considerably more common.
Whether the one type of poisoning or the other occurs
under these circumstances is due in part to the character

of the explosion, since if definite partial burning of the
explosive takes place the risk of nitrous fumes poisoning’
is especially great. But the result will depend also on
the duration of exposure. Unless carbon monoxide is
present in large amounts, it takes times to produce its
effects. On the other hand, the records abundantly
show that quite a,brief exposure to even small,quantities
of nitrous fumes is sufficient to produce serious or fatal
poisoning from this source. For the same reason, drift-
ing fumes from blasting will typically cause nitrous
fumes poisoning, and persons may be “ gassed ” in this
way by the fumes from blasting which has taken place
at some considerable distance. Sometimes one or more
of a party working in close proximity may be affected,
while others escape.

Mixed poisoning must sometimes occur, but the
number in which the evidence points to the probability
of such a conjunction is surprisingly small. One or
other type is almost invariably markedly predominant.
I know of no case, in which a man, who had been ren-
dered unconscious by carbon monoxide and had then
recovered, developed later on signs of nitrous fumes
poisoning. On the other hand, it is probable that carbon
monoxide may co-operate in some cases of nitrous fumes
poisoning in aggravating and prolonging the initial
symptoms.

(2)	In the second class of “ gassing ” accidents, expo-
sure was delayed until several hours after blasting. They
occurred when the working places were entered on the
following shift. They were caused by the stagnation of
blasting fumes in close places owing to defective local
ventilation, due, either to the miner responsible having
neglected to use the means of ventilation provided, or
less commonly to the fact that the means of ventilation
provided were inadequate.

There were 28 accidents of this nature during the four
years under review. Two features stand out :■—

(1)	Of the 28, 21 occurred in winzes, owing to workers
(usually natives) entering the winze before the fumes
had been blown out—a circumstance which shows the
necessity for more particular attention being directed to
the ventilation of this type of working. In one of the
original cases, and in two which occurred more recently,
the interval blasting and exposure was as long as 40
hours, namely, from the Saturday afternoon till the
following Monday morning. This fact indicates how
long the fumes may remain present in dangerous quan-
tities in such workings, unless they are properly
dispelled.

(2)	In every instance in this class, carbon monoxide
was the predominant cause of death, no doubt with
carbon dioxide co-operating in some cases. Nitrous
fumes poisoning never occurs under these conditions. It
is only caused when the exposure occurs immediately or
shortly after blasting, or after the actual burning of
explosives. It is not merely that the carbon monoxide

present, by producing rapid and often fatal results, fore-
stals and obscures the delayed effects of the more slowly
acting poison. Two of the 39 fatalities which occurred
happened’ amongst those engaged in attempting to rescue
the men overcome. But there is no history in all these
cases of any of those engaged in rescue work, and
temporarily affected by carbon monoxide . (and there
were a good many who suffered in this way), afterwards
developing symptoms of nitrous fumes poisoning.

As I have said elsewhere, “ the majority are due either
(and most frequently) to pure carelessness on the part
of miners in neglecting to use the means of local ventila-
tion at hand to blow out close places before setting their
gangs to work, and in some cases in returning too soon
to their working places after blasting, before the fumes'
have been dispersed, or to the lack of provision of
adequate means of local ventilation by those
responsible.”

(b)	Accidents Due to Explosives being Accidentally
Set on Fire and Burned.—The number of observations
which have been made on the composition;of the fumes
actually evolved when nitro-glycerine explosives are
burned in air is not large. Recorded results vary con-
siderably, and the actual results, which occurs when
accidents from this cause happen underground, also5pro-
bably varies between rather wide limits. Dr. Moir has
supplied me with the following figures :—■

Table B.

Quantity in cubic feet of Gases Produced by Ilb. of
Blasting Gelatine under Different Circumstances.

Conditions. . CO2. N2. CO. NO.

A.	Perfect explosion, without

wrapper ________	6-2 ... 2-9 ... — ... —

B.	“Practical” explosion,

with wrapper ..........	5-5 ... 2-9 ... 0-9 ...	?

C.	Burned without wrapper

in excess of air ...... 5-7 ... 2*3 ... 0*7 ... 1’2

D.	Burned in vacuo ....  	—■. ... — ... 6*0 ... 5’0

When burning takes place in the dead end of a- drive

or similar place, combustion might be expected to begin
as in C, and to finish as in D, according to the available
air. The calculations are for pressure and temperature
at a depth of 1,500 ft. These being the determining
conditions, one might conclude that nitrous fumes
poisoning would be the type of gassing most frequently
met with when explosives are set on fire underground,
but that carbon monoxide poisoning may also occur.
Experience shows that this is actually so.

First-Aid Treatment.

In all cases of gas poisoning prompt and efficient first-
aid treatment is of the first importance. Several of
those attempting rescue, working with misdirected
heroism, have in the past lost their lives, and many more
have been temporarily overcome, through ignorance or
heedlessness of the risks they have run, or sometimes
from lack of the provision of adequate-means of local
ventilation.

The following points are to be remembered in attempt-
ing rescue :—

(1)	When a gassing accident happens, the first thing
to do is at once to turn on compressed air into the place
in which is has occurred, and to keep it turned on
throughout. This at once supplies those overcome with
purer air, and makes it safer for rescuers to enter the
danger zone. It seems an obvious precaution to take,
but neglect to do so has not. infrequently resulted in
disaster to those attempting rescue, and in fatal delay
in extricating those already overcome. No one should
enter the danger zone until it has been well blown out
for several minutes.

(2)	No man must enter the danger zone alone. Loss
of life has occurred from this. Four men are the proper
number to form a rescue party, so that if one is disabled
the others may be able to help him. Men who have
already been engaged in rescue work should not enter,
the danger zone a second time if fresh men are available.

(3)	Rescuers should carry with them one or two
candles to test the air, and also electric lamps, or, fail-
ing these, acetylene lamps. . Never take it for granted
that the air is safe because candles continue to burn,
but always regard it as an urgent danger signal’if candles
burn low or go out. If this happens, rescuers should
at once withdraw, and wait until the place has been
more thoroughly blown out, unless rescue can be effected
immediately and easily.

(4)	The next thing to do is. to bring the affected man
as quickly as possible to the nearest place where the air
is fresh, and then at once to attend to the breathing. To
bring the man to the surface before commencing treat-
ment will, in bad cases, give that treatment little chance
of success, and in cases where artificial respiration is
required the delay will render treatment hopeless. Yet
this sort of thing still happens.

The routine first-aid treatment recommended is as
follows :—

(a) In slight cases, where the man is conscious and
quite able to swallow, the usual treatment is to give a
dose of emetic (copper or zinc sulphate are commonly
employed), and when that has acted, to follow with, a
dose of sal volatile.

This procedure is to be adopted both in cases of
carbon monoxide poisoning and of suspected nitrous
fumes poisoning, the object being that the act of vomit-
ing will help to express mucus and gas from the lungs.
There is no doubt that effectual vomiting gives great
relief, and is a valuable safeguard against after effects,
particularly in nitrous fumes poisoning.

fb) In all cases of carbon monoxide poisoning of any
severity oxygen should be administered.

(c)	When the man is unconscious oxygen should
invariably be given, and persevered with until con-
sciousness is restored. When breathing is obviously
failing, artificial respiration must be employed as well.
Either Sylvester’s or Schafer’s method may be used.
The former is commonly more convenient on the wet
and uneven surfaces of mine ground, but the latter is
rather more effectual, and should be used when circum-
stances permit.

In desperate cases, where breathing has ceased, the
use of artificial respiration may sometimes be possible
on the spot where the man is first found, provided that
the place has first been well blown out. To do so
requires courage and judgment, but it has saved life in
at least one case within my knowledge.

(d)	The man must be kept warm throughout by extra
covering, friction of the limbs, etc. He must not be
allowed to exert himself too soon, since the carbon
monoxide poisoning exertion may readily cause a dan-
gerous exaggeration of the condition. On no account,
even in comparatively slight cases, should the affected
man be allowed to walk home. Hot strong coffee should
be given, and alcohol should be avoided.

(a) All cases of carbon monoxide poisoning of any
severity should be sent to hospital, and this rule’should
invariably be followed where the circumstances suggest
that nitrous fumes poisoning may have occurred. It is
most important to keep, these cases under observation,
since the danger. of acute symptoms setting in after
apparent temporary recovery is always present. . The
medical attendant of the patient should be notified , in
all eases of gassing, particularly when poisoning by
fumes is'suspected.

I may offer a few additioiial notes. First, regarding
the use of oxygen. The simple oxygen cylinder with