1,3-benzenediamine, 4,4'-[1,3-propanediylbis(oxy)]bis-, tetrahydrochloride: Human health tier II assessment

03 July 2015

CAS Number: 74918-21-1

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This assessment was carried out by staff of the National Industrial Chemicals Notification and Assessment Scheme (NICNAS) using the Inventory Multi-tiered Assessment and Prioritisation (IMAP) framework.

The IMAP framework addresses the human health and environmental impacts of previously unassessed industrial chemicals listed on the Australian Inventory of Chemical Substances (the Inventory).

The framework was developed with significant input from stakeholders and provides a more rapid, flexible and transparent approach for the assessment of chemicals listed on the Inventory.

Stage One of the implementation of this framework, which lasted four years from 1 July 2012, examined 3000 chemicals meeting characteristics identified by stakeholders as needing priority assessment. This included chemicals for which NICNAS already held exposure information, chemicals identified as a concern or for which regulatory action had been taken overseas, and chemicals detected in international studies analysing chemicals present in babies’ umbilical cord blood.

Stage Two of IMAP began in July 2016. We are continuing to assess chemicals on the Inventory, including chemicals identified as a concern for which action has been taken overseas and chemicals that can be rapidly identified and assessed by using Stage One information. We are also continuing to publish information for chemicals on the Inventory that pose a low risk to human health or the environment or both. This work provides efficiencies and enables us to identify higher risk chemicals requiring assessment.

The IMAP framework is a science and risk-based model designed to align the assessment effort with the human health and environmental impacts of chemicals. It has three tiers of assessment, with the assessment effort increasing with each tier. The Tier I assessment is a high throughput approach using tabulated electronic data. The Tier II assessment is an evaluation of risk on a substance-by-substance or chemical category-by-category basis. Tier III assessments are conducted to address specific concerns that could not be resolved during the Tier II assessment.

These assessments are carried out by staff employed by the Australian Government Department of Health and the Australian Government Department of the Environment and Energy. The human health and environment risk assessments are conducted and published separately, using information available at the time, and may be undertaken at different tiers.

This chemical or group of chemicals are being assessed at Tier II because the Tier I assessment indicated that it needed further investigation.

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NICNAS has made every effort to assure the quality of information available in this report. However, before relying on it for a specific purpose, users should obtain advice relevant to their particular circumstances. This report has been prepared by NICNAS using a range of sources, including information from databases maintained by third parties, which include data supplied by industry. NICNAS has not verified and cannot guarantee the correctness of all information obtained from those databases. Reproduction or further distribution of this information may be subject to copyright protection. Use of this information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner. NICNAS does not take any responsibility whatsoever for any copyright or other infringements that may be caused by using this information.

Acronyms & Abbreviations

Chemical Identity

Synonyms 1,3-benzenediamine, 4,4-[1,3-propanediylbis(oxy) ] bis-, tetrahydrochloride
1,3-bis-(2,4-diaminophenoxy)propane tetrahydrochloride

Structural Formula Structural formula of 1,3-benzenediamine, 4,4'-[1,3-propanediylbis(oxy)]bis-, tetrahydrochloride
Molecular Formula C15H20N4O2.4ClH
Molecular Weight (g/mol) 434.1926
Appearance and Odour (where available) White to off-white powder
SMILES c1(OCCCOc2c(N)cc(N)cc2)c(N)cc(N)cc1_Cl_Cl_Cl_Cl


The chemical is on the 'List of chemicals used as dyes in permanent and semi-permanent hair dyes in Australia' with a reported cosmetic use in permanent hair dye preparations (NICNAS, 2007).


The following international uses have been identified through: the European Commission Cosmetic Ingredients and Substances (CosIng) database; the United States (US) Personal Care Product Council International Nomenclature of Cosmetic Ingredients (INCI) Dictionary; the US National Library of Medicine's Hazardous Substances Data Bank (HSDB); and the European Union (EU) Scientific Committee on Consumer Safety opinion (SCCS, 2007).

The chemical has reported cosmetic use as a component of hair dyes.

The chemical has reported site-limited use as an intermediate producing oxidative and non-oxidative hair dye formulations.


No known restrictions have been identified.


The chemical is listed on the following:

  • EU Cosmetics Regulation 1223/2009 Annex III—List of substances which cosmetic products must not contain except subject to the restrictions laid down: maximum concentration in cosmetic formulation must not exceed 1.2 % calculated as free base (1.8 % as tetrahydrochloride salt). The Cosmetics Regulation also mandates label warning statements relating to the sensitisation potential of the chemical;
  • The Association of Southeast Asian Nations (ASEAN) Cosmetic Directive Annex III—Part 1—List of substances which cosmetic products must not contain except subject to restrictions and conditions laid down; and
  • New Zealand Cosmetic Products Group Standard—Schedule 5—Table 1: Components cosmetic products must not contain except subject to the restrictions and conditions laid down.

Existing Work Health and Safety Controls

Hazard Classification

The chemical is not listed on the Hazardous Substances Information System (HSIS) (Safe Work Australia).


No specific exposure standards are available.


No specific exposure standards are available.

The chemical, 1,3-benzenediamine, 4,4'-[1,3-propanediyl bis(oxy)]bis-, tetrahydrochloride (CAS No. 74918-21-1) is used as an intermediate in producing oxidative and non-oxidative hair dyes and remains in the final product formulation at low concentrations. The chemical also exists as a free base (1,3-benzenediamine, 4,4’-[1,3-propanediylbis(oxy)]bis-) (CAS No. 81892-72-0).


Limited toxicokinetic data are available for this chemical.

The dermal absorption of the chemical was assessed in an in vitro test system using skin explants harvested from suckling pigs (aged 6–8 weeks). The chemical was tested as a component of a cream formulation (with or without hydrogen peroxide (H2O2)) and as an aqueous solution. Explants were exposed to the chemical for 30 minutes. Mean values for percutaneous absorption were 1.34 ± 0.697 µg/cm2 (formulation with H2O2), 1.696 ± 0.682 µg/cm2 (formulation without H2O2), 0.670 ± 0.635 µg/cm2 (aqueous solution) (SCCS, 2007).


The chemical has low acute toxicity based on results from animal tests following oral exposure. The median lethal dose (LD50) in rats is 3570 mg/kg bw.  

The chemical was assessed in a non-guideline acute oral toxicity study in male Wistar rats (10 animals/group). The animals were dosed by oral gavage at 2510, 3160, 3570, 3980 or 5010 mg/kg bodyweight (bw). Animals were observed for 14 days. Mortalities occurred in the groups as follows: 0/10 (2510 mg/kg bw), 2/10 (3160 mg/kg bw), 5/10 (3570 mg/kg bw), 8/10 (3980 mg/kg bw), and 9/10 (5010 mg/kg bw). An LD50 of 3570 mg/kg bw was determined from this study (SCCS, 2007).


No data are available.


No data are available.

Skin Irritation

The chemical was found to cause mild, transient skin irritation in a study in New Zealand White rabbits..

The chemical was assessed according to the Organisation for Economic Co-operation and Development (OECD) test guideline (TG) 404 (acute dermal irritation/corrosion) where 0.5 g of the moistened substance was applied to the intact, shaved back skin of three New Zealand White rabbits. The test chemical was left in place for four hours under a semi-occlusive patch. The application resulted in slight erythema on the exposed skin of all rabbits at one hour after treatment. No oedema was observed and no evidence of irreversible damage was apparent. Under these test conditions, the test substance caused minimal and transient irritation of the skin (SCCS, 2007).

Eye Irritation

The chemical was reported to irritate the eyes when tested according to OECD TG 405 (acute eye irritation/corrosion). The corneal, iridial, conjunctival (redness) and conjunctival (chemosis) scores were given as (1/1/3/4). However, the effects were reversible within 14 days of application.

The chemical was assessed in an ocular irritation study similar to OECD TG 405. The chemical (approximately 45.2 mg as an undiluted solution) was instilled into the conjunctival sac of one eye each of three New Zealand White rabbits and left for 24 hours. The chemical caused corneal injury including opacity (maximum grade 1 in all animals up to 72 hours after instillation) and epithelial damage (maximum 65 % of the corneal surface, 24 hours after instillation). Corneal injury resolved within 72 hours. Iridial irritation (grade 1) was observed in all animals but resolved during the observation period. Conjunctival irritation consisted of redness (up to grade 3), chemosis (up to grade 4) and discharge (up to grade 2) and had completely resolved in one animal within seven days and in the other animals within 14 days. No mortalities or evidence of systemic toxicity were observed. Under the conditions of the study, the test substance was irritating to rabbit eyes (SCCS, 2007).

Skin Sensitisation

The chemical is considered to be a slight skin sensitiser based on the positive results seen in a single local lymph node assay. The EC3 (estimated concentration required to produce a 3-fold increase in lymphocyte proliferation) was 14.7 %.

The potential for the chemical to promote allergic sensitisation was investigated in a study conducted according to OECD TG 429 (skin sensitisation: local lymph node assay). Female CBA/J mice (five animals/group) were topically administered the chemical in solution on the dorsal surface of each ear lobe once daily, for three consecutive days at 5, 25 and 50 % (in ethanol/water mixture (7/3, volume/volume)). The rate of radio-labelled thymidine (3HTdR) incorporation in the lymph nodes was used to calculate stimulation indices (SI). Even at the highest concentration, no skin effects were noted on the skin of the ears. The SI for the different dose groups were 1.2 ± 1.0 (5 %), 4.9 ± 1.1 (25 %) and 4.3 ± 1.0 (50 %), respectively. An EC3 value of 14.7 % was calculated. On the basis of this finding, the test chemical is considered to be a skin sensitiser (SCCS, 2007).


In a 90-day oral gavage study in rats, a no observed adverse effect level (NOAEL) of 40 mg/kg bw/day was reported.

The chemical was assessed for toxicity following repeated oral dosing in a study conducted according to OECD TG 408 (repeated dose 90-day oral toxicity study in rodents). Crl:(WI)BR Wistar rats (12 animals/sex/group) were dosed with the chemical by gavage for 13 weeks at 0, 40, 130 or 360 mg/kg bw/day. Discolouration and brown staining was evident in several tissues in the high dose group. Some ocular pathology was evident in the mid and high dose groups. Reduced weight gain was also evident in high dose males. The mid and high dose groups also exhibited significant changes in organ weights (thymus, adrenal glands, spleen and kidneys). Some cardiac degeneration was evident in the mid and high dose groups. Two mortalities were recorded in the two highest dose groups; however, evaluation at necropsy showed no clear cause of death. Minor haematological changes were reported for the low dose group; however, these were not considered adverse effects associated with treatment. There were no treatment-related changes in food consumption in any group. On the basis of these findings, an NOAEL of 40 mg/kg bw/day was determined (SCCS, 2007).


No data are available.


No data are available.


Based on the weight of evidence from the available in vitro and in vivo genotoxicity studies, the chemical is not considered to be genotoxic. Some in vitro genotoxicity tests gave positive results, but all in vivo tests were negative.

In vitro

In a bacterial reverse mutation assay, conducted according to OECD TG 471 (bacterial reverse mutation test), the chemical was incubated with Salmonella typhimurium strains TA98, TA100, TA102, TA1535 and TA1537 at concentrations ranging from 33 to 5000 µg/plate, in the presence or absence of a metabolic activation system. The chemical did not cause any statistically significant increase in the number of revertant colonies in any of the strains tested, at any concentration, in the presence or absence of a metabolic activation system. The chemical was not considered to be genotoxic under these experimental conditions (SCCS, 2007).

In an OECD TG 476 (in vitro mammalian cell gene mutation test) study, the chemical was incubated with mouse lymphoma L5178Y cells, in the presence or absence of a metabolic activation system, at concentrations of 37.5–1100 µg/mL. Mutations in the target gene, thymidine kinase, were assessed as a marker of genotoxicity. The test chemical failed to induce any statistically significant increase in mutations at the target locus and, therefore, the chemical was not considered to be mutagenic in this mouse lymphoma assay (SCCS, 2007).

In a test performed according to OECD TG 473 (in vitro mammalian chromosome aberration test), Chinese hamster ovary (CHO) cells were treated with the test chemical for four hours at 300, 400  or 500 µg/mL without metabolic activation or 800, 1000 or 1200 µg/mL with metabolic activation. Both in the absence and in the presence of metabolic activation, statistically significant, concentration-dependent increases in the number of cells with structural chromosomal aberrations were observed after treatment. Increases were observed in the number of polypoid and endomitotic metaphases. On the basis of these findings, the test chemical was determined to be clastogenic in vitro (SCCS, 2007).

In vivo

In a study conducted according to OECD TG 474 (mammalian erythrocyte micronucleus test), NMRI mice (six/sex/group) were administered the test chemical via intraperitoneal injection at 0, 62.5, 125 or 250 mg/kg bw. Bone marrow cells were harvested from the mice 24 hours after exposure. The test chemical did not induce an increase in the number of polychromatic erythrocytes with micronuclei and was therefore considered not to be genotoxic in vivo under these experimental conditions (SCCS, 2007).

In a non-guideline in vivo unscheduled DNA synthesis test, CF HB Wistar rats (three/group) were administered the test chemical at 1000 or 2000 mg/kg by oral gavage. Hepatocytes were harvested from the animals and treated with [3H]-thymidine for a period of four hours. Nuclear and cytoplasmic grains were counted separately and the cytoplasmic counts were subtracted from the nuclear counts to give net grain/nucleus. The test chemical did not cause an increase in unscheduled DNA synthesis in primary hepatocytes and, therefore, was not considered to be genotoxic in vivo (SCCS, 2007).


No data are available.

Based on the results, a reported NOAEL of 180 mg/kg bw/day was determined for maternal and foetal toxicity.

In a non-guideline study, female Sprague Dawley rats (21 animals/group) were administered the chemical by oral gavage on gestation days 6–15, at 0, 20, 60 or 180 mg/kg bw/day. No maternal deaths occurred during the study and dams did not exhibit any evidence of a toxic response to the test chemical at any dose. There was no evidence that the test chemical had any influence on the outcome of pregnancy. Resorption rates and post-implantation losses were not affected by treatment. No foetal effects of treatment were observed. On the basis of these findings, an NOAEL of 180 mg/kg bw/day, was determined for foetal and maternal toxicity (SCCS, 2007).

Critical Health Effects

The critical health effects for risk characterisation include local effects (skin sensitisation and eye irritation).

Public Risk Characterisation

The chemical was reported to be used in permanent hair dye preparations in Australia (NICNAS, 2007).

The EU has restricted the use of this chemical in hair dye preparations to a maximum of 1.8 % concentration in ready-to-use hair dye formulations (see International restrictions).

Currently, there are no restrictions in Australia on using this chemical in hair dyes. The eye irritation and skin sensitisation risk could be mitigated by implementing concentration limits for use in hair dyes.

Occupational Risk Characterisation

During product formulation, dermal and ocular exposure may occur, particularly where manual or open processes are used. These could include transfer and blending activities, quality control analysis, and cleaning and maintaining equipment. Worker exposure to the chemical at lower concentrations could also occur while using formulated products containing the chemical. The level and route of exposure will vary depending on the method of application and work practices employed.

Given the critical local health effects, the chemical could pose an unreasonable risk to workers unless adequate control measures to minimise dermal and ocular exposure are implemented. The chemical should be appropriately classified and labelled to ensure that a person conducting a business or undertaking (PCBU) at a workplace (such as an employer) has adequate information to determine the appropriate controls.

The data available support an amendment to the hazard classification in the HSIS (Safe Work Australia) (refer to Recommendation section.

NICNAS Recommendation

Further risk management is required. Sufficient information is available to recommend that risks to public health and safety from the potential use of the chemical in cosmetics and/or domestic products be managed through changes to poisons scheduling, and risks for workplace health and safety be managed through changes to classification and labelling.

Assessment of the chemical is considered to be sufficient, provided that risk management recommendations are implemented and all requirements are met under workplace health and safety and poisons legislation as adopted by the relevant state or territory.

Public Health

Given the risk characterisation, it is recommended that the chemicals should be included in the Poisons Standard (the Standard for the Uniform Scheduling of Medicines and Poisons—SUSMP) for hair dye use. Matters to be taken into consideration include that the:

  • chemical has low acute oral toxicity (LD50 in rats is 3570 mg/kg bw);
  • chemical is an eye irritant;
  • chemical is a moderate skin sensitiser with an LLNA EC3 value of 14.7 %;
  • chemical is restricted to 1.8 % in cosmetics in the EU; and
  • sensitisation risk can be minimised by including warning statements on the label when the chemical is present at any concentration, as has been mandated in the EU.
Work Health and Safety

The chemical is recommended for classification and labelling under the current approved criteria and adopted GHS as below. This assessment does not consider classification of physical and environmental hazards.

Hazard Approved Criteria (HSIS)a GHS Classification (HCIS)b
Irritation / Corrosivity Irritating to eyes (Xi; R36) Causes serious eye irritation - Cat. 2A (H319)
Sensitisation May cause sensitisation by skin contact (Xi; R43) May cause an allergic skin reaction - Cat. 1 (H317)

a Approved Criteria for Classifying Hazardous Substances [NOHSC:1008(2004)].

b Globally Harmonized System of Classification and Labelling of Chemicals (GHS) United Nations, 2009. Third Edition.

* Existing Hazard Classification. No change recommended to this classification

Advice for consumers

Products containing the chemicals should be used according to the instructions on the label.

Advice for industry

Control measures

Control measures to minimise the risk from dermal and ocular exposure to the chemical should be implemented in accordance with the hierarchy of controls. Approaches to minimise risk include substitution, isolation and engineering controls. Measures required to eliminate, or minimise risk arising from storing, handling and using a hazardous chemical depend on the physical form and the manner in which the chemical is used. Examples of control measures which could minimise the risk include, but are not limited to:

  • using closed systems or isolating operations;  
  • health monitoring for any worker who is at risk of exposure to the chemical, if valid techniques are available to monitor the effect on the worker’s health;
  • minimising manual processes and work tasks through automating processes;
  • work procedures that minimise splashes and spills;
  • regularly cleaning equipment and work areas; and
  • using protective equipment that is designed, constructed, and operated to ensure that the worker does not come into contact with the chemical.

Guidance on managing risks from hazardous chemicals are provided in the Managing risks of hazardous chemicals in the workplace—Code of practice available on the Safe Work Australia website.

Personal protective equipment should not solely be relied upon to control risk and should only be used when all other reasonably practicable control measures do not eliminate or sufficiently minimise risk. Guidance in selecting personal protective equipment can be obtained from Australian, Australian/New Zealand or other approved standards.

Obligations under workplace health and safety legislation

Information in this report should be taken into account to help meet obligations under workplace health and safety legislation as adopted by the relevant state or territory. This includes, but is not limited to:

  • ensuring that hazardous chemicals are correctly classified and labelled;
  • ensuring that (material) safety data sheets ((M)SDS) containing accurate information about the hazards (relating to both health hazards and physicochemical (physical) hazards) of the chemical are prepared; and
  • managing risks arising from storing, handling and using a hazardous chemical.

Your work health and safety regulator should be contacted for information on the work health and safety laws in your jurisdiction.

Information on how to prepare an (M)SDS and how to label containers of hazardous chemicals are provided in relevant codes of practice such as the Preparation of safety data sheets for hazardous chemicals—Code of practice and Labelling of workplace hazardous chemicals—Code of practice, respectively. These codes of practice are available from the Safe Work Australia website.

A review of the physical hazards of the chemical has not been undertaken as part of this assessment.


European Commission Cosmetic Ingredients and Substances (CosIng) Database. Accessed April 2015 at

Hazardous Substances Data Bank (HSDB). National Library of Medicine. Accessed April 2015 at

National Industrial Chemicals Notification and Assessment Scheme (NICNAS) 2007. List of Chemicals used as Dyes in Permanent and Semi-Permanent Hair Dyes in Australia.

Safe Work Australia (SWA). Hazardous Substances Information system (HSIS). Accessed April 2015 at

Scientific Committee on Consumer Safety (SCCS) 2007. Opinion on 1,3-bis-(2,4-Diaminophenoxy)propane. Colipa No. A79. Accessed April 2015

United States (US) Personal Care Product Council International Nomenclature of Cosmetic Ingredients (INCI) dictionary. Accessed March 2015 at

Last update 03 July 2015