Sodium azide

Endpoint summary

Description of key information

The acute oral toxicity of sodium azide was evaluated in five acute oral toxicity studies available in the public literature. Based on the results and following a weight-of-evidence approach, the LD₅₀ value of 27 mg/kg bw was chosen as the key parameter. Therefore, the classification of sodium azide as acute Tox.2, H300 in accordance with Annex VI of the CLP Regulation 1272/2008 is warranted.

In an acute inhalation toxicity study conducted according to EPA OPPTS 870.1300, the LC₅₀ for acute inhalation toxicity ranged from 0.054 to 0.52 mg/L in male and female rats. Therefore, the classification of sodium azide as Acute Tox.2, H330 according to CLP Regulation 1272/2008 is warranted.

Furthermore, the acute dermal toxicity of sodium azide was evaluated in four acute dermal toxicity studies available in the public literature. Based on the results and following a weight-of-evidence approach, the LD₅₀ value of 18 mg/kg bw was chosen as the key parameter. Therefore, the classification of sodium azide as Acute Tox.1, H310, according to CLP Regulation 1272/2008, is warranted.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Remarks:

review article which gives not sufficient information on experimental details

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

no data

GLP compliance:

not specified

Test type:

other: no data

Limit test:

no

Specific details on test material used for the study:

no data

Species:

mouse

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

no data

Route of administration:

oral: unspecified

Vehicle:

not specified

Details on oral exposure:

no data

Doses:

no data

No. of animals per sex per dose:

no data

Control animals:

not specified

Details on study design:

no data

Statistics:

no data

Preliminary study:

no data

Sex:

not specified

Dose descriptor:

LD50

Effect level:

27 mg/kg bw

Mortality:

no data

Clinical signs:

other: no data

Gross pathology:

no data

Other findings:

no data

Interpretation of results:

Category 2 based on GHS criteria

Conclusions:

Although lacking methodological details, the LD50 (mouse oral) was reported to be 27 mg/kg bw.

Executive summary:

 In an acute oral toxicity study cited in a review article, mice were given a single oral dose of sodium azide (dose levels not specified). Although lacking methodological details, the LD50 (mouse oral) was reported to be 27 mg/kg bw. Applying the Globally Harmonised Classification System, the given data support the classification as Category 2 (LD50 > 5 to 50 mg/kg bw) or as Acute Tox. 2, H300 in accordance with Annex VI of CLP Regulation 1272/2008.

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

: <5 animals per dose group, non data on feeding/housing, inappropriate dose levels, no LD50 calculated, no pathology/necropsy performed

Principles of method if other than guideline:

no data

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

no data

Route of administration:

oral: unspecified

Vehicle:

not specified

Details on oral exposure:

no data

Doses:

40, 42, 44, 45, 46, 48, 60 mg/kg bw

No. of animals per sex per dose:

2-8 animals per dose group

Control animals:

not specified

Details on study design:

no data

Statistics:

no data

Preliminary study:

no data

Sex:

not specified

Dose descriptor:

LD50

Effect level:

44 mg/kg bw

Remarks on result:

other: assessed from given data

Sex:

not specified

Dose descriptor:

LD50

Effect level:

42 mg/kg bw

Remarks on result:

other: assessed from given data

Mortality:

see Table 1 below

Clinical signs:

other: no data

Gross pathology:

no data

Other findings:

no data

Table 1: The effect of oral administration of sodium azide in rats

Number of rats	Dose [mg/kg BW]	Died in 3 hours	Mortality [%]
3	40	0	0
2	42	1	50
2	44	1	50
8	45	5	62
3	46	3	100
3	48	3	100
3	60	3	100

Interpretation of results:

Category 2 based on GHS criteria

Conclusions:

From the available data, the LD50 (rat, oral) can be estimated to be 42 mg/kg bw. Applying the Globally Harmonised Classification System, sodium azide can be classified as Category 2 (LD50 > 5 to 50 mg/kg bw) or as Acute Tox. 2, H300 in accordance with Annex VI of CLP Regulation 1272/2008.

Executive summary:

In an acute oral toxicity study, rats (n= 2 -8 per dose) were given a single oral dose of sodium azide at levels of 40, 42, 44, 45, 46, 48 and 60 mg/kg bw. At dose levels of 42 and 44 mg/kg, 50% of the animals died within 3 hours after administration, which gives an indication of the LD50 to be in the range 42 mg/kg bw although inadequate dose levels were selected for this study. Therefore, based on the results from this study, applying the Globally Harmonised Classification System, sodium azide can be classified as Category 2 (LD50 > 5 to 50 mg/kg bw) or as Acute Tox. 2, H300 in accordance with Annex VI of CLP Regulation 1272/2008.

Reference 3

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Remarks:

review article which gives not sufficient information on experimental details

Qualifier:

no guideline followed

Principles of method if other than guideline:

no data

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Species:

mouse

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

no data

Route of administration:

oral: unspecified

Vehicle:

not specified

Details on oral exposure:

no data

Doses:

no data

No. of animals per sex per dose:

no data

Control animals:

not specified

Details on study design:

no data

Statistics:

no data

Preliminary study:

no data

Sex:

not specified

Dose descriptor:

LD50

Effect level:

37.4 mg/kg bw

Mortality:

no data

Clinical signs:

other: no data

Gross pathology:

no data

Other findings:

no data

Interpretation of results:

Category 2 based on GHS criteria

Conclusions:

From the available data, the LD50 (mouse, oral) can be estimated to be <50 mg/kg bw, which is consistent with the classification as Category 2 (LD50 > 5 to 50 mg/kg bw) according to the Globally Harmonised Classification System or Acute Tox. 2, H300 according to Annex VI of CLP Regulation 1272/2008.

Executive summary:

 In an acute oral toxicity study cited in a review article, mice were given a single oral dose of sodium azide (dose levels not specified). Although lacking methodological details, the LD50 (mouse oral) was reported to be < 50 mg/kg bw. Applying the Globally Harmonised Classification System, the given data support the classification as Category 2 (LD50 > 5 to 50 mg/kg bw) or as Acute Tox. 2, H300 in accordance with Annex VI of CLP Regulation 1272/2008.

Reference 4

Endpoint:

acute toxicity: oral

Type of information:

other: handbook data

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Qualifier:

no guideline followed

Principles of method if other than guideline:

no data

GLP compliance:

not specified

Test type:

other: no data

Limit test:

no

Species:

rabbit

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

no data

Route of administration:

oral: unspecified

Vehicle:

not specified

Details on oral exposure:

no data

Doses:

no data

No. of animals per sex per dose:

no data

Control animals:

not specified

Details on study design:

no data

Statistics:

no data

Preliminary study:

no data

Sex:

not specified

Dose descriptor:

LD50

Effect level:

10 mg/kg bw

Mortality:

no data

Clinical signs:

other: no data

Gross pathology:

no data

Other findings:

no data

Interpretation of results:

Category 2 based on GHS criteria

Conclusions:

The LD50 (rabbit, oral) was reported to be 10 mg/kg bw.

Executive summary:

The LD50 (rabbit, oral) was reported to be 10 mg/kg bw. Applying the Globally Harmonised Classification System, the given data support the classification as Category 2 (LD50 > 5 to 50 mg/kg bw) or as Acute Tox. 2, H300 in accordance with Annex VI of CLP Regulation 1272/2008.

Reference 5

Endpoint:

acute toxicity: oral

Type of information:

other: handbook data

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Qualifier:

no guideline followed

Principles of method if other than guideline:

no data

GLP compliance:

not specified

Test type:

other: no data

Limit test:

no

Species:

rat

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

no data

Route of administration:

oral: unspecified

Vehicle:

not specified

Details on oral exposure:

no data

Doses:

no data

No. of animals per sex per dose:

no data

Control animals:

not specified

Details on study design:

no data

Statistics:

no data

Preliminary study:

no data

Sex:

not specified

Dose descriptor:

LD50

Effect level:

27 mg/kg bw

Sex:

not specified

Dose descriptor:

LD50

Effect level:

>= 35.9 - <= 70.9 mg/kg bw

Remarks on result:

other: when applied in a granular form, containing 8 - 16% sodium azide

Mortality:

no data

Clinical signs:

other: no data

Gross pathology:

no data

Other findings:

no data

Interpretation of results:

Category 2 based on GHS criteria

Conclusions:

The LD50 (rat, oral) for sodium azide was reported to be 27 mg/kg bw. When applied in a granular preparation containing 8 and 16% sodium azide the LD50 was 786 and 443 mg/kg bw, respectively, corresponding to a sodium azide concentration of 63 -71 mg/kg bw.

Executive summary:

In an acute oral toxicity study with rats, the LD50 for sodium azide was reported to be 27 mg/kg bw. When applied in a granular preparation containing 8 and 16% sodium azide the LD50 was 786 and 443 mg/kg bw, respectively, corresponding to a sodium azide concentration of 63 -71 mg/kg bw. Under the given concentrations and the assumption that sodium azide in a granular preparation has a poorer bioavailability, resulting in a higher LD50, sodium azide is classified as Category 2 according to GHS criteria or as Acute Tox. 2, H300 according to Annex VI of CLP Regulation 1272/2008.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

27 mg/kg bw

Quality of whole database:

Weight of evidence

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008-05-16 to 2009-12-02

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Version / remarks:

1998

Deviations:

no

GLP compliance:

yes

Test type:

traditional method

Limit test:

no

Specific details on test material used for the study:

- Lot: #C-07A005 and #C-08V701
- Composition: >95% pure
- Physical appearance: White solid, similar in appearance to typical table salt
- pH: 9+
- Solubility: Soluble in water
- Stability: Test substance was expected to be stable for the duration of testing
- Expiration Date: Not Applicable
- Treatment of the test material prior testing: Prior to aerosolization, the test substance was ground in a ball mill for 24 hours and then further ground in a coffee mill (Cuisinart, Model #DC0-20) until it passed through a 425 micrometer sieve (USA standard).

Species:

rat

Strain:

Sprague-Dawley

Remarks:

albino

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Ace Animals, Inc., Boyertown, PA
- Females (if applicable) nulliparous and non-pregnant: Yes
- Age at study initiation: Young adult (9-10 weeks) /
- Weight at study initiation: males 280-338 grams and females 190-236
- Housing: The animals were singly housed in suspended stainless steel caging with mesh floors. Litter paper was placed beneath the cage and was changed at least three times per week.
- Diet: Purina Rodent Chow #5012
- Water (e.g. ad libitum): Yes
- Acclimation period: 14-18 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-24°C
- Humidity (%): 66-79%
- Photoperiod (hrs dark / hrs light): 12 / 12

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

air

Mass median aerodynamic diameter (MMAD):

> 3.5 - < 3.7 µm

Geometric standard deviation (GSD):

> 1.88 - < 2.16

Remark on MMAD/GSD:

The aerodynamic mass median diameter and geometric standard deviation were determined graphically using two-cycle logarithmic probit axes.

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Mini-Nose Only Inhalation Chamber by ADG Developments LTD
- Exposure chamber volume: 6. 7 L
- Method of holding animals in test chamber: Polycarbonate holding tubes which seal to the chamber with an "O" ring during exposure.
- Source of air: Air compressor by JUN-AIR
- System of generating particulates/aerosols: Wright Dust Generator driven by a variable speed motor by Dayton
- Method of particle size determination: Eight-stage Andersen cascade impactor

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: An eight-stage Andersen cascade impactor was used to assess the particle size distribution of the test atmosphere. Samples were withdrawn from the breathing zone of the animals at two intervals. The filter paper collection stages were weighed before and after sampling to determine the mass collected upon each stage.
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): The aerodynamic mass median diameter and geometric standard deviation were determined graphically using two-cycle logarithmic probit axes. See table 1 under "Any other information on materials and methods incl. tables"

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

See table 1 under "Any other information on materials and methods incl. tables"

No. of animals per sex per dose:

5 males and 5 females per dose/ 3 doses

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of weighing: Prior to exposure and again on Days 7 and 14 or after death
- Frequency of observation: At least once daily for up to 14 days following exposure or until death occured
- Necropsy of survivors performed: yes
- Examinations performed: mortality, signs of toxicity, behavioral changes, body weight

Statistics:

Mean + / - Standard Deviation

Preliminary study:

See table 1 under "Any other information on materials and methods incl. tables"

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 0.054 - < 0.52 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

- At 2.02 mg/L exposure level, all animals died within 190 minutes of exposure to the test atmosphere
- At 0.52 mg/L exposure level, four male and four female rats died during exposure to the test atmosphere
- At 0.0542 mg/L exposure level, no mortality was observed

Clinical signs:

other: - At 0.52 mg/L exposure level, the surviving animals were hypoactive and exhibited hunched posture, abnormal respiration and nasal discharge - At 0.0542 mg/L exposure level, all animals exhibited ocular and nasal discharge.

Body weight:

- At 0.52 mg/L exposure level, all surviving animals recovered by Day 3, gained body weight and appeared active and healthy for the remainder 14-day observation period.
- At 0.0542 mg/L exposure level, body weight was shown to increase over the observation period

Gross pathology:

- At 2.02 mg/L exposure level, gross necropsy of the decedents revealed red, edematous lungs, normal trachea and clear wet nasal discharge.
- At 0.52 mg/L exposure level, gross necropsy of the decedents revealed red, edematous lungs, normal trachea and clear wet nasal discharge. No gross abnormalities were noted for the euthanized animal when necropsied at the conclusion of the 14-day observation period.
- At 0.0542 mg/L exposure level, no gross abnormalities were observed

Interpretation of results:

Category 2 based on GHS criteria

Conclusions:

In conclusion, the acute inhalation toxicity of sodium azide, as determined in a study according to EPA guideline OPPTS 870.1300, lies between an LC50 (4 h) of 0.054 and 0.52 mg /L in male and female rats.

Executive summary:

In an acute inhalation toxicity study according to EPA guideline OPPTS 870.1300, groups of young adult Sprague Dawley rats (5/sex) were exposed at test concentrations of 0.054, 0.52 and 2 mg/L via the inhalation route (nose only) to Sodium azide (>95% purity) in compressed air for 4 hours. After exposure, the animals were observed for a period of 14 days. At test concentration of 0.52 and 2.0 mg/L, mortality was observed. An increase in body weight was seen at 0.054 mg/L and gross pathology at test concentrations 0.52 and 2.0 mg/L revealed red, edematous lungs, normal trachea and clear wet nasal discharge. Thus, under the conditions of this study, the single exposure acute inhalation LC50 of the test substance is between 0.054 and 0.52 mg/L in male and female rats. Therefore classification as Acute Tox.2 (H330) according to CLP Regulation 1272/2008 is warranted.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

> 0.054 - < 0.52 mg/L air

Quality of whole database:

Guideline study

Acute toxicity: via dermal route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: dermal

Type of information:

other: handbook data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

no data

GLP compliance:

not specified

Test type:

other: not reported

Species:

rabbit

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

no data

Type of coverage:

not specified

Vehicle:

not specified

Details on dermal exposure:

no data

Duration of exposure:

no data

Doses:

no data

No. of animals per sex per dose:

no data

Control animals:

not specified

Details on study design:

no data

Statistics:

no data

Preliminary study:

no data

Sex:

not specified

Dose descriptor:

LD50

Effect level:

20 mg/kg bw

Mortality:

no data

Clinical signs:

other: no data

Gross pathology:

no data

Other findings:

no data

Interpretation of results:

Category 1 based on GHS criteria

Conclusions:

A dermal LD50 of 20 mg/kg bw sodium azide has been reported for rabbit.

Executive summary:

A dermal LD50 of 20 mg/kg bw of sodium azide has been reported for the rabbit. Applying the Globally Harmonised Classification System, this value would classify sodium azide as Category 1 or as Acute Tox. 1, H310 in accordance with the CLP Regulation 1272/2008.

Reference 2

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

unsuitable test system

Qualifier:

according to guideline

Guideline:

other: OECD guideline 404 (acute dermal irritation/corrosion)

Deviations:

yes

Remarks:

1 and 4h exposure

GLP compliance:

not specified

Test type:

fixed dose procedure

Species:

rabbit

Strain:

other: New Zealand, unspecified

Sex:

male/female

Type of coverage:

other: semi-occlusive & occlusive

Vehicle:

unchanged (no vehicle)

Duration of exposure:

4 h

Doses:

0.5 g

No. of animals per sex per dose:

6 animals per dose

Control animals:

not specified

Sex:

male/female

Dose descriptor:

LD50

Effect level:

>= 500 - <= 1 000 mg/kg bw

Remarks on result:

other: Estimation from given data (animal weight 2-4kg, applicated dose 4 x 0.5g per animal)

Mortality:

3 animals were found dead after 1 hour exposure

Clinical signs:

other: no data

Gross pathology:

no data

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

In a dermal irritation study according to OECD 404, three of six animals exposed to 4 x 0.5 g of sodium azide died 1 h / 4 h treatment. As the weight of the rabbits was 2-4 kg, the LD50 (rabbit, dermal) can be estimated to range between 500 - 1000 mg/kg bw.

Executive summary:

In a defined method for the determination of irritant and corrosive effects (OECD 404, 1981), the effects of varying the exposure time and the extent of occlusion were investigated and compared in rabbit skin experiments (by occlusive and semi-occlusive methods, each at exposure times of 1 hr and 4 hr). Results showed that, independent from treatment, three of six animals of each group were found dead after dermal exposure to 4 x 0.5g of sodium azide. As the weight of the rabbits was 2-4 kg, the LD50 (rabbit, dermal) can be estimated to range between 500 - 1000 mg/kg bw. The benchmarks for toxicity categorization according to GHS are acute toxicity estimates (LD50) of 200-1000 (toxicity category III) which is covered by the estimated LD50.

Reference 3

Endpoint:

acute toxicity: dermal

Type of information:

other: data collection

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Principles of method if other than guideline:

No method description provided

GLP compliance:

not specified

Test type:

other: not specified

Species:

rabbit

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

no data

Type of coverage:

not specified

Vehicle:

not specified

Details on dermal exposure:

no data

Duration of exposure:

no data

Doses:

no data

No. of animals per sex per dose:

no data

Control animals:

not specified

Details on study design:

no data

Statistics:

no data

Preliminary study:

no data

Sex:

not specified

Dose descriptor:

other: LD

Effect level:

>= 18 - <= 60 mg/kg bw

Mortality:

no data

Clinical signs:

other: no data

Gross pathology:

no data

Other findings:

no data

Interpretation of results:

study cannot be used for classification

Conclusions:

In the data collection published by the Scientific Committee for Occupational Exposure Limits (SCOEL), LD values (rabbit dermal) of 18-60 mg/kg bw are reported.

Executive summary:

In the data collection published by the Scientific Committee for Occupational Exposure Limits (SCOEL), LD values (rabbit dermal) of 18-60 mg/kg bw are reported, based on two studies conducted by Bassendowska et al. (Medycyna Pracy 1961, 12: 427-42 and Medycyna Pracy 1965, 16: 187-99). The test conditions are not mentioned in the SCOEL publication. Therefore the study cannot be used for classification.

Reference 4

Endpoint:

acute toxicity: dermal

Type of information:

other: handbook data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

no data

GLP compliance:

not specified

Test type:

other: not specified

Species:

rabbit

Strain:

other: albino

Sex:

not specified

Details on test animals or test system and environmental conditions:

no data

Type of coverage:

not specified

Vehicle:

other: granular formulation containing 8-16% sodium azide

Details on dermal exposure:

no data

Duration of exposure:

no data

Doses:

no data

No. of animals per sex per dose:

no data

Control animals:

not specified

Details on study design:

no data

Statistics:

no data

Preliminary study:

no data

Sex:

not specified

Dose descriptor:

LD50

Effect level:

>= 118 - <= 600 mg/kg bw

Remarks on result:

other: applicated as granular formulation containing 8 - 16% sodium azide

Sex:

not specified

Dose descriptor:

LD50

Effect level:

>= 19 - <= 48 mg/kg bw

Remarks on result:

other: calculated sodium azide concentration in the granular formulation containing 8 - 16% sodium azide

Mortality:

no data

Clinical signs:

other: no data

Gross pathology:

no data

Other findings:

no data

Interpretation of results:

Category 1 based on GHS criteria

Conclusions:

The acute dermal LD50 (rabbit dermal) of a granular formulation containing 8 and 16% Sodium azide was reported to be 600 and 118 mg/kg bw, corresponding to a concentration of 48 and 19 mg/kg of pure sodium azide,respectively.

Executive summary:

The acute dermal LD50 (rabbit dermal) of a granular formulation containing 8 and 16% sodium azide was reported to be 600 and 118 mg/kg bw, corresponding to a concentration of 48 and 19 mg/kg of pure sodium azide. Applying the Globally Harmonised Classification System, sodium azide can be classified as Category 1 (LD50 > 0 to 50 mg/kg bw dermal) or as Acute Tox. 1, H310 according to CLP Regulation 1272/2008.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

18 mg/kg bw

Quality of whole database:

Weight of evidence

Additional information

Acute oral toxicity:

In the literature, four LD₅₀ values for acute oral toxicity in rodents (mouse, rat) in the range of 27-42 mg/kg bw were reported. As the four reports are quite consistent and using a conservative benchmark, the lowest value of 27 mg/kg bw (which was observed in 2 different species) can be used as key parameter. Furthermore, the results of a 14d study on rats which died at day 2 after ingestion of ≥20 mg/kg bw strengthen the reported values. Rabbits seem to be more sensitive towards Sodium azide than rodents as one entry mentions a LD₅₀ (rabbit, oral) of 10 mg/kg bw. As the reliability of this study cannot be assessed because no methodological details were given and the other four entries are for the most part consistent, the value 27 mg/kg bw was chosen as key parameter.

 

Acute inhalation toxicity:

The only available study on acute inhalation toxicity was that of Durando (2009), who exposed rats via nose-only inhalation route to vapour of sodium azide for 4 hours. At test concentration of 0.52 and 2.0 mg/L, mortality was observed. An increase in body weight was seen at 0.054 mg/L and gross pathology at test concentrations 0.52 and 2 mg/L revealed red, edematous lungs, normal trachea and clear wet nasal discharge. Thus, under the conditions of this study, the single exposure acute inhalation LC₅₀ of the test substance is between 0.054 and 0.52 mg/L in male and female rats. 

 

Acute dermal toxicity:

Four different studies were available focussing on dermal toxicity of which three give consistent results of LD₅₀ (rat, dermal) = 18-60 mg/kg bw although these data are not experimentally assessed by the authors but only cited from other sources which were to date not available. The fourth value, estimated from the study of Potokar et al. (1985) is derived from a skin corrosion/irritation experiment in which 3 of 6 rabbits died after application of 500-1000 mg/kg bw Sodium azide to their skin.

 

Study	Species	Marker
Oral toxicity
Fairhall 1943	Rat	LD50 = 42 mg/kg bw
WSSA	Rat	LD50 = 27 mg/kg bw
Graham 1949	Mouse	LD50 = 27 mg/kg bw
Gregory 1978	Mouse	LD50 = 37.4 mg/kg bw
WSSA	Rabbit	LD50 = 10 mg/kg bw
Inhalation toxicity
Durando J.	Rat	LC50 = between 0.054 and 0.52 mg/L
Dermal toxicity
ACGIH 1991	Rabbit	LD50 = 20 mg/kg bw
Potokar 1985	Rabbit	LD50 = 500-1000 mg/kg bw
SCOEL 2008	Rabbit	LD50 = 18-60 mg/kg bw
WSSA 1983	Rabbit	LD50 = 19-48 mg/kg bw

 

Justification for classification or non-classification

Acute oral toxicity:

All five studies report LD50 values for rodents or rabbit in the concentration range 10-42 mg/kg bw, the classification of sodium azide as Acute Tox. 2, H300 ("Fatal if swallowed) in accordance with Annex VI of CLP Regulation 1272/2008 is therefore warranted.

 

Acute dermal toxicity:

Two different sources report LD50 values for rabbits in the concentration range 18-48 mg/kg bw, which allows categorization into toxicity category I, ranging from 0-50 mg/kg bw. Another report slightly exceeds this benchmark, reporting a dermal toxicity of 18-60 mg/kg bw but using a conservative apporoach, the classification of sodium azide as Acute Tox.1, H310 ("Fatal in contact with skin") in accordance with CLP Regulation 1272/2008 is therefore warranted.

 

Acute inhalation toxicity:

The available study leads to a LC50 (rat, inhalation) between 0.054 and 0.52 mg/L for sodium azide. Based on this study, the classification of sodium azide as Acute Tox.2, H330 ("Fatal if inhaled") in accordance with CLP Regulation 1272/2008 is therefore warranted.