Since the introduction of Chinese products about 8 years ago, there is another cause - products that are not formulated for safety. Brands that use excessive amounts of high risk ingredients and/or illegal ingredients. They do this because it increases wear time, requires less skill and knowledge to use, and the products are much easier to develop (so lower development costs).
I can't say this is the case for all Chinese products, but I have seen enough SDS and MSDS with serious errors or omissions, have seen that most of the illegal "effects" gel polishes originate in China, and also noticed that a massive increase in allergies happened since these products became available and many new brands, with uneducated owners, appeared.
The only reason for a company to want to sell products from China, is that the costs are much lower and you can buy in small quantities. To give an example, today you can buy a 15ml bottle of gel polish direct from a Chinese factory for less than £1, that is already filled and labelled. A 15ml of gel polish from a EU or USA factory would cost very much more because of the cost of quality ingredients and the additional time to develop the product.
This means that you can buy 100 bottles from China of different colours, for approximately £100. To be able to offer 100 different colours of EU/USA gel polish, the cost can be as high as £90,000 because the product costs are higher, you have to buy more, you have to pay for the bottles, filling, labels and someone to apply the labels. And because you have to buy so much more, you need a warehouse and can't sell from home (I discovered on brand in Europe selling from an 8th floor apartment, which is a real fire risk).
Legal protection
Just as a brand has to be able to prove "due diligence", so too does a nail salon (or any business owner and Director). If a client develops an allergy or onycholysis - which happened hundreds of times in the UK last year - and reports this to Trading Standards, the salon may have to demonstrate in Court that it took all reasonable care to use safe legal products and that the manufacturers recommendations were followed. The insurance company would do everything possible to avoid a payout and probably hire experts to discredit the salon.
If the salon used products from a highly respected brand, who claimed (true or not) that these were manufactured in EU/USA, then due diligence could be relatively easy to prove. But if purchased from an unknown company, whose website was illegal, that sold Chinese products, that may be much less easy to do - and there are many brands in Europe doing exactly this, because they know that many NT are kind, trusting people.
Since I came into the industry 14 years ago, I have met or been in contact with hundreds (perhaps thousands) of NT who developed allergies, many who ultimately had to give up a career that they loved.
This is why we started to create hypoallergenic products, why I have done a lot of research on this topic, and also why I created the "Nail Technicians Allergy Support Group" on Facebook and the website
www.saynotoallergies.today to provide fact-based information.
I honestly don't care which products NT use because this is always a decision of personal choice, providing that the products are safe and legal. I don't think it is fair or reasonable for any brand to sell potentially risky products, or to cut corners by ignoring laws and regulations.
If that is allowed to continue, why wouldn't all other brands do the same to cut their costs and increase sales? Then where will this industry be when filled with cowboy companies and high risk products? This can lead to further regulation, for example requiring Nail Tech's to pass new exams, or the authorities banning important ingredients (which they are considering).