Hair extensions and straightening are all the rage for women - regardless of whether they're celebrities, politicians, or just everyday people. But the treatments often use chemicals that can be harmful to health.

Hollywood celebrities go mad for instant glamour, and hair extensions and hair straighteners can instantly transform the thinnest, dullest hair into lustrous, long strands.

Singer Jessica Simpson is making a fortune from her own brand of hair extensions. The cost ranges from $100 to $500 to chemically straighten, and from $100 to up to several thousand dollars for top quality extensions made from 100 per cent human hair.

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But these treatments can be tortuous, total failures, and some straightening chemicals are highly dangerous.

Experts don't normally use glue, instead a protein polymer bond that dissolves away, or wefts, which are sewn into the natural hair.

Ordinary hairdressing salons are equipped with huge air ventilator pipes and vents, and both clients and stylists wear industrial-strength gas masks, just to have their hair straightened with the same dangerous treatments that have been used time and time again on thousands of Australian heads.

Certain hair-straightening products contain highly toxic, carcinogenic chemicals, with potentially serious side-effects. Many brands have been recalled, but the fear is that many salons are still using the unsafe straightening solutions that contain dangerously high levels of formaldehyde.

Nutritionist and registered nurse, Sam Beau Patrick, known as the Health Queen, is a strong advocate for healthy products. She deplores risky hair-straightening products.

“They have diabolical effects. In the acute setting you can absorb some of the products through your scalp. It's the hairdresser that's exposed to it all the time that's the greatest risk, because they're absorbing it through their hands, and they're breathing it in.”

Independent tests have exposed a raft of hair-straighteners that contain illegal and unsafe levels of free formaldehyde.

• Brazilian Blowout Professional Smoothing Solution
• Keratin Complex Intense RX
• Smoothing Therapy
• Smoothing Therapy for Blond Hair
• Express Blowout
• Hydrospa Keratin Smoothing Treatment
• Global Keratin Taming System with Juvexin Light Wave and Curly
• Guava Latino

In Canada a class action's been mounted against Brazilian Blowout, the most popular hair-straightener here and overseas. It's now banned, and been replaced by Brazilian Blowout Zero. The problem is that the makers of the original Brazilian Blowout claimed it was safe, and that there was no Formaldehyde in the product.

Vancouver Hair Stylist Miranda Scott started the class action, and 1000 people have joined, to sue Brazilian Blowout's manufacturers.

“When the clients were getting the service done, their eyes were stinging. The stylist’s eyes would sting, they would be watery, we couldn't breathe - it felt like there was a weight in your chest, headaches, a sort of fogginess of your mind,” Scott said. “We would have the door wide open. We installed a ventilation system, but none of it worked.”

So far, no Australians have joined the class action, but Miranda Scott hopes it will raise standards of accountability in the industry. “We use so many chemicals in our industry to begin with, and I think all companies that produce products for us need to be reliable and honest.”

• The Health Queen - www.healthqueen.com.au
• Product Safety Recalls Australia - www.recalls.gov.au
• Australian Competition and Consumer Commission - www.accc.gov.au
• Product Safety Australia - www.productsafety.gov.au
• Therapeutic Goods Administration - www.tga.gov.au
• National Industrial Chemicals Notification and Assessment Scheme - www.nicnas.gov.au