Acetylene

Direct observations: clinical cases, poisoning incidents and other

Administrative data

Endpoint:

direct observations: clinical cases, poisoning incidents and other

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP, non-guideline human experimental study, predates implementation of GLP and/or development of study guidelines. Limitations in reporting but otherwise acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1925

Materials and methods

Study type:

study with volunteers

Endpoint addressed:

acute toxicity: inhalation

Test guideline

Qualifier:

no guideline available

Deviations:

not applicable

Principles of method if other than guideline:

Subjects were exposed to discontinuous inhalations of acetylene of various concentrations.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Acetylene

EC Number:

200-816-9

EC Name:

Acetylene

Cas Number:

74-86-2

Molecular formula:

C2H2

IUPAC Name:

acetylene

Details on test material:

- Source: Bon-Accord Acetylene Gas Company
- Prepared from calcium carbide and purified through a lime tower
- No further details

Method

Type of population:

not specified

Subjects:

No data

Ethical approval:

not specified

Route of exposure:

inhalation

Reason of exposure:

intentional

Exposure assessment:

measured

Details on exposure:

Mixtures of acetylene gas with oxygen were administered from a Douglas bag with the subject in a sitting position and no re-breathing. The concentrations administered were as follows:
0 % to 35 % acetylene: 100,000, 150,000, 200,000, 250,000, 300,000, 330,000 and 350,000 ppm
(50% acetylene caused an unbearable feeling of suffocation within 70 seconds and experiment was stopped)

Examinations:

- Clinical signs were monitored and the concentration that produced unconsciousness (and exposure time) was listed
- The effects of acetylene inhalation on memory, reflex times and muscular movement were also assessed

Medical treatment:

No data

Results and discussion

Clinical signs:

The lowest concentration employed, 10%, caused feelings of mild intoxication and paraesthesia. 15% caused distinct intoxication and 20% caused marked intoxication after one hour exposure.

Results of examinations:

Systemic LOAEC: 1 hour inhalation exposure at 10% (100,000 ppm or 107,000 mg/m3 equivalent) caused mild intoxication and paraesthesia. NOAEC for local irritation: 20% (200,000 ppm, equivalent to 214,000 mg/m3)

Any other information on results incl. tables

The lowest concentration employed, 10%, caused feelings of mild intoxication and paraesthesia.

15% caused distinct intoxication with talkativeness, sleepiness and inability to walk in a straight line.

20% caused marked intoxication after one hour exposure.

25% acetylene caused similar but more marked symptoms.

General uncoordination and aggressive behaviour were noted after inhalation of 30% acetylene for 13 minutes

Inhalation of 33% acetylene caused unconsciousness in 6 - 7 minutes and 35% acetylene in 5 - 5.5 minutes.

50% acetylene produced feelings of intense intoxication within 35 seconds and an unbearable feeling of suffocation in 70 seconds (after which the experiment was stopped).

Incoordination was seen after 4-5, 6, 12-13, 15 and 18 minutes at 35, 33, 30, 25 and 20% respectively.

Unconsciousness occurred at 5 – 5.5 minutes at 35% and 6 – 7 minutes at 33%.

Times of onset of other clinical observations

 

Conc of Acetylene	Effects observed
	Initial intoxication	Marked intoxication	Talkativeness	Noisy talkativeness	Aggression
35%	25 sec	60 sec	1.5 – 2 min	2.5 – 3 min	3.5 – 4 min
33%	30 sec	70 sec	3 min	3 – 4 min	5 min
30%	30 sec	90 sec	3 – 4 min	4 – 5 min	8 – 10 min
25%	40 sec	120 sec	3.5 – 4.5 min	5 – 6 min	10 -12 min
20%	50 sec	4 min	6 min	11 min	-

 

Applicant's summary and conclusion

Conclusions:

Systemic LOAEC: 1 hour inhalation exposure at 10% (100,000 ppm or 107,000 mg/m3 equivalent) caused mild intoxication and paraesthesia. NOAEC for local irritation: 20% (200,000 ppm, equivalent to 214,000 mg/m3)

Executive summary:

A group of human volunteers was exposed to acetylene at a range of concentrations in order to assess its anaesthetic properties. The lowest concentration employed, 10%, caused feelings of mild intoxication and paraesthesia.

Systemic LOAEC: 1 hour inhalation exposure at 10% (100,000 ppm or 107,000 mg/m3 equivalent).

There was no indication of local irritation effects at 20% for 1 hour (or higher exposures but >20% were less than 1 hour).

NOAEC for local irritation: 20% (200,000 ppm, equivalent to 214,000 mg/m³)