1-[[4-(Phenylazo)phenyl]azo]- 2-Naphthalenol (Solvent Red 23)

CAS Registry Number 85-86-9

The Final Screening Assessment for Solvent Red 23 was published on September 10, 2009 as part of Batch 6 of the Challenge initiative of the Chemicals Management Plan (CMP). The assessment is summarized on this web page. This substance was also included in the assessment of Certain Solvent Dyes.

What is it

1-[[4-(Phenylazo)phenyl]azo]- 2-naphthalenol, also known as Solvent Red 23, is a red dye.

Solvent Red 23 is used primarily in cosmetics and personal care products. It is also used as a colourant in commercial pesticides.
The only identified commercial product containing Solvent Red 23 is used as a hard surface disinfectant. No personal care products regulated as drugs, as per the Food and Drug Regulations, have been identified to contain this substance.
This substance is not manufactured in Canada but is imported into Canada.

Prior to assessment, Solvent Red 23 was identified as a potential concern to the environment based on information regarding possible persistence, accumulation in organisms, and potential to cause harm to organisms.
Solvent Red 23 was not considered to be a high priority for assessment of potential risks to human health; however, potential health effects were also evaluated in this screening assessment.

Solvent Red 23 may be released to the environment during consumer use.
A significant proportion of the substance is estimated to be released to wastewaters. Solvent Red 23 is expected to bind to sewage sludge at sewage treatment plants and be sent to landfills. In addition, Solvent Red 23 may be released to soil as a component of an agricultural pesticide.

People in Canada may be exposed to Solvent Red 23 when using cosmetics and personal care products that may contain this substance; however, this exposure is expected to be low.

The Government conducted a science-based evaluation of Solvent Red 23 called a screening assessment.
Screening assessments address potential for harm to the general population and the environment.
Results of the final screening assessment indicate that although Solvent Red 23 has the potential to remain in the environment for a long time, it is not expected to accumulate in organisms.
Furthermore, the quantity of Solvent Red 23 that may be released to the environment is below the level expected to cause harm to organisms.
The Government concluded that Solvent Red 23 is not entering the environment in a quantity or under conditions that constitute a danger to the environment.
The Government also concluded that Solvent Red 23 may be harmful to human health.

Exposure of the general population of Canada to Solvent Red 23 is expected to be low and the Government is proposing additional action so that exposure remains low.
The Government is proposing to include Solvent Red 23 as a prohibited or restricted ingredient on Health Canada's Cosmetic Ingredient Hotlist. The Hotlist is used to communicate that certain substances may not be compliant with requirements of the Food and Drugs Act or the Cosmetic Regulations. Under Canadian legislation, cosmetics that contain substances that are harmful to the user cannot be sold.
The proposal within the risk management scope to amend the Food and Drugs Regulations which currently permits the use of this colourant in drugs for external use only, remains under consideration.
Solvent Red 23 is part of the solvent dyes subgroup of the Aromatic Azo and Benzidine-based substances Grouping. The screening assessment for Certain Azo Solvent Dyes was published on May 28, 2016.
The Government took risk management actions on Solvent Red 23 to address ecological concerns. Information on additional risk management actions for Solvent Red 23 is available.

The health risks associated with a chemical depend on the hazard (its potential to cause adverse health effects) and the dose (the amount of chemical to which a person is exposed). Exposure to the general population to Solvent Red 23 is expected to be low.
As a general precaution, people in Canada are reminded to carefully follow safety warnings and directions that may appear on a product label when using any product.
People in Canada who handle Solvent Red 23 in the workplace should consult with their occupational health and safety representative about safe handling practices, applicable laws and requirements under the Workplace Hazardous Materials Information System (WHMIS).