Owing to Hong Kong’s humid climate, to avoid musty-smelling laundry dried indoors or to maintain a pleasant fragrance in clothing, some consumers may opt to use in-wash scent boosters when doing laundry, yet it may trigger allergic reactions or pollute the environment. The Consumer Council tested 12 models of in-wash scent boosters and all were found to contain varying types and concentrations of fragrance allergens, with the highest of a total of 8 types found in 1 model. Frequent exposure to fragrance allergens through various means may increase the risk of developing allergic reactions. Currently, there is no legislation in Hong Kong mandating the labelling of fragrance allergens in household cleaning or laundry products. Referencing the relevant requirements of European Union (EU) regulations, the concentrations of certain fragrance allergens found in 10 models reached the labelling threshold. Furthermore, 4 models were detected with galaxolide (HHCB), a synthetic musk compound that is not readily biodegradable, potentially impacting marine ecosystems in the long term. The Council considers these in-wash scent boosters as unnecessary add-ons for laundry as the contained fragrances have no effect on cleaning, while the cost per wash could reach a maximum of $21 based on the recommended usage. As such, consumers should consider the long-term need for these products, especially if they or their family members are prone to skin or respiratory allergies. Should consumers choose to use these products, they should exercise caution when using, and at the same time keep them out of young children’s reach to avoid accidental ingestion.
The Council purchased 12 in-wash scent booster models from different retail outlets for testing, priced between $38 to $179 per bottle, with 6 models claiming fabric softening properties. Based on a laundry load of 6kg or above and using the recommended dosage or 1 capful, the cost per wash ranged from $3 to $21. Assuming that the product is used 4 times per week, the annual total cost could range from $621 to $4,358, which could add up in the long run, thus consumers should carefully evaluate the necessity for these products.
Fragrance Allergens Found in All Models
Only 1 Carried a Scant Labelling
According to a report published by the American Contact Dermatitis Society, laundering products are a significant contributor to the development of allergic contact dermatitis (ACD). Test results showed that all 12 in-wash scent booster models contained fragrance allergens, with total amounts ranging from 0.0023% to 0.672%. Except for 1 model with only 1 type of fragrance allergen, the remaining 11 models had 3 to 8 types of fragrance allergens. The test also revealed that models with two-coloured scented granules generally had more types of fragrance allergens, averaging 6 types compared to almost 4 types in single-coloured ones.
Currently, Hong Kong has no legislation mandating the labelling of fragrance allergens in household cleaning and laundry products. Referencing the EU’s Detergents Regulation, products containing any of the 26 fragrance allergens at concentrations exceeding 0.01% must be labelled to alert consumers and help prevent allergic reactions and related symptoms. Over 80% (10) of the models were detected with specific fragrance allergens at concentrations exceeding 0.01%, reaching the level set out in EU’s labelling requirement. However, only 1 model listed such information on its label, without specifying the type of the fragrance allergen.
During wash cycles, the scent boosters will become greatly diluted in water. In general, higher concentrations and more types of fragrance allergens detected, coupled with high recommended dosage, as well as the overall product formulation and the usage method, etc., may all affect the types and the amounts of fragrance residues left in textiles after washing.
4 Models Detected with HHCB
Environmental Impact Not To be Overlooked
Musk compounds may be added into some products to help the fragrance bind to textiles. According to the EU’s newly amended Cosmetics Regulation, with effect from 31 July 2028, HHCB present in rinse-off products at concentrations exceeding 0.01% must be labelled; the labelling requirement also applies for detergents. 4 tested models were found to contain HHCB at levels ranging from 0.14% to 0.73%, reaching the labelling threshold.
HHCB is commonly used in products such as air fresheners, cleaning products and laundry detergents. A risk assessment report by the US Environmental Protection Agency estimated that over 90% of HHCB is released into municipal wastewater. As HHCB is not readily biodegradable and highly toxic to aquatic organisms, the continued discharge of this substance may endanger marine ecosystems. Given the widespread detection of HHCB in wastewater in many countries, the potential environmental impact of using HHCB-containing products should not be overlooked.
Certain organisations in the United States, Australia and Japan, have suggested that for some people, exposure to scented consumer goods (e.g. laundry products, perfumes, deodorisers, etc.) may trigger adverse reactions such as asthma, migraines, respiratory and skin problems, and even rashes when using strongly scented laundry products. These reactions are not only confined to the users but may affect others as well. Considering the concerns over “second-hand scents”, consumers should choose products not only based on personal preferences, but also taking into account the feelings of others around them.
Labelling Information Lacked Transparency
Vague Instructions May Easily Lead to Overuse
Although most models were found with various fragrance allergens and/or environmental pollutant HHCB, the completeness and transparency of their labelling had much room for improvement. 2 models lacked ingredient lists entirely, while the remaining 10 models listed generic types without specifying the chemical names, making it impossible for consumers to discern the ingredients of the product and determine its suitability for use.
User instructions were also unclear for some models, with 2 only stating “use an appropriate amount”, and 2 stating a general range such as 2 to 3 capfuls. It is worth noting that many models suggested consumers to adjust the usage amount according to their own preferences, and some even suggested doubling the amount. Without proper usage instructions, consumers are more likely to overuse the products, potentially leading to increased fragrance residues on fabrics and increasing the risk of developing respiratory and skin allergies.
The Council calls on manufacturers to be mindful of fragrance allergens and musk compounds in their products, review formulations and minimise or lower the concentration of those substances or ingredients as far as possible, so as to minimise the impact on the user and ecosystem. They should also improve labelling by listing key ingredients (including fragrance allergens) as well as the dosage clearly. The Council also recommends manufacturers to offer refill packs to reduce plastic waste.
The Council also anticipates relevant authorities to conduct tests on detergents and laundry products to assess the concentration of allergenic fragrances, and examine the need for regulation and to impose appropriate safety and labelling requirements on these products in a timely manner.
As in-wash scent boosters have no cleaning effects but may pose allergy risks or environmental pollution, while also incurring considerable per-use costs, consumers are reminded to consider the necessity before purchase. Should such products really be needed, consumers can refer to the following tips:
- Avoid frequent use and be mindful of the dosage. As a precaution, avoid using on clothing and products for babies and toddlers, or people with eczema or skin allergies;
- Check the product claims when choosing laundry products. For example, if the laundry detergent already has softening function, avoid using additional in-wash scent boosters that claim to have a softening effect to prevent unnecessary product overuse;
- Most products are designed for machine washing. Load them directly into the drum of the machine instead of the drawers for detergent or fabric softener to avoid clogging due to incomplete dissolution;
- Avoid using wash cycles with less water or shorter durations, to avoid leaving excessive amount of detergent and/or scent booster residue on clothing;
- Maintain good ventilation during washing and drying to avoid build-up of fragrance from the scent boosters which can deteriorate indoor air quality;
- Some laundry scent boosters look and smell like candies. Parents should store them in places inaccessible to children to avoid accidental ingestion;
- If the purpose of use is to remove bad odours, try soaking clothes in diluted baking soda or vinegar before considering the use of scent boosters.
Download the article (Chinese only): https://ccchoice.org/577-wash-scent
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