Histidine

Flammability

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

flammable solids

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.10 (Flammability (Solids))

GLP compliance:

yes

Specific details on test material used for the study:

Batch no.: P816P001
Expiry date: 03-01-2019
Storage: room temperature (20+/-5°C), away from light and humidity

Key result

Test procedure:

burning rate test over 100 mm length

Remarks:

Note: actual length of powder train: 250 mm

Remarks on result:

substance does not ignite and propagate combustion either by burning with flame or smouldering along 200 mm of the powder train within the 2 minutes test period

The burning rate could not be determined because ignition did not occur within 2 minutes.

Interpretation of results:

not classified based on GHS criteria

Conclusions:

The amino acid is non flammable.

Executive summary:

In this study the flammability of L-Histidine was assessed according to the EU method A.10. The study is GLP.

First, a safety test was performed for safety reasons. The test item melted to a yellowish liquid, which decomposed under colour change over brown to black and a black residue remained. Second, a preliminary screening test was performed. The test item was heated with the flame of a gas burner for two minutes, but ignition did not occur. The test item melted to a yellowish red liquid and became black. Under further heating the molten test item bloated and glowed in contact with the flame, but no signs of flammability were observed. Since ignition did not occur throughout the course of the test it was not necessary to determine the burning rate.

No observations were made which might cause doubts concerning the validity of the study outcome.

According to the CLP legislation a powdered substance shall be classified as readily combustible solid when the time of burning of one or more of the test runs, performed in accordance with the test method, is less than 45 seconds or the rate of burning is more than 2,2 mm/s.

As L-Histidine did not even ignite, it should be considered as non flammable.

Reference 2

Endpoint:

substances / mixtures which in contact with water emit flammable gases

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.12 (Flammability (Contact with Water))

Principles of method if other than guideline:

Batch no.: P816P001
Expiry date: 03-01-2019
Storage: room temperature (20+/-5°C), away from light and humidity

GLP compliance:

yes

Key result

Test procedure:

step 1

step 2

step 3

step 4

Max. rate of gas release:

0.34 L/kg h

Identity of evolved gas:

unknown

Interpretation of results:

not classified based on GHS criteria

Conclusions:

The amino acid is not flammable in contact with water.

Executive summary:

This study was performed in order to determine the flammability (contact with water) of L-Histidine. The EU method A.12 was followed and the study was GLP.

The test item showed negative results during the first 3 steps of the test. During the last step L-Histidine showed some gas production with an evolution rate of less than 1 L/(kg*h) after contact with water.

Therefore, L-Histidine is considered as non flammable.

Reference 3

Endpoint:

pyrophoric solids

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study is recently performed according to OECD and GLP. The study is well documented and conducted.

Qualifier:

according to guideline

Guideline:

EU Method A.13 (Pyrophoric Properties of Solids and Liquids)

GLP compliance:

yes

Specific details on test material used for the study:

Batch no.: P816P001
Expiry date: 03-01-2019
Storage: room temperature (20+/-5°C), away from light and humidity

Key result

Test procedure:

ignition time on contact with air

Temp.:

22.7 °C

Remarks on result:

no ignition on contact with air (not further specified)

Interpretation of results:

not classified based on GHS criteria

Conclusions:

The amino acid is not pyrophoric.

Executive summary:

In this study the pyrophoric properties of L-Histidine were determined according to the EU method A.13. The study is GLP.

Six independent experiments were performed. No ignition occurred in either of them.

Description of key information

L-Histidine does not or very slightly ignite, no signs of flammability or propagation of a flame are observed and gas production is minimal.
Therefore, L-histidine should be considered as non flammable.

Furthermore, L-histidine did not ignite upon contact with water, nor was it found to be pyrophoric.

Key value for chemical safety assessment

Flammability:

non flammable

Additional information

In a very recent study the flammability of L-Histidine was assessed according to the EU method A.10. The test item did not ignite during the course of the test. The test item melted to a yellowish red liquid and became black. Under further heating the molten test item bloated and glowed in contact with the flame, but no signs of flammability were observed.

In a second study the flammability in contact with water was assessed following the EU method A.12. The test item showed negative results during the first 3 steps of the test, and some gas production with an evolution rate of less than 1 L/(kg*h) after contact with water in a last step of the test.

In a third study the pyrophoric properties of L-Histidine were determined according to the EU method A.13. The study is GLP.

Six independent experiments were performed. No ignition occurred in either of them.

In an older supporting study (Schaub, 1980) the amino acid was found to have a low level of combustibility. However, the short ignition rapidly extinguished. There was no propagation of the fire.

Justification for classification or non-classification

According to the CLP regulation a powdered substance shall be classified as readily combustible solid when the time of burning of one or more of the test runs, performed in accordance with the test method, is less than 45 seconds or the rate of burning is more than 2,2 mm/s.

Taken together all results, L-Histidine does not or very slightly ignite, no signs of flammability or propagation of a flame is observed and gas production is minimal.

Therefore, L-Histidine should be considered as non flammable.