Last month, the beauty world was rattled when the occupational health agency in Oregon found significant levels of formaldehyde in the hair-smoothing solution sold under the name Brazilian Blowout. The agency said it had conducted lab tests after receiving numerous complaints from stylists citing nosebleeds, breathing problems and eye irritation after applying the product.
While some salons have stopped using the products all together, other salons have built special rooms for the treatment and even started using industrial-strength respirators as a safety precaution.
Is it really that serious? (source)