Formaldehyde is a well-known toxic agent, therefore having a highly regulated status. Despite, some cosmetic firms recently introduced high and illegal concentrations of formaldehyde in hair treatments for increasing straightening and long-lasting performances. The objective of this study was to assess how and to which extent, these products may disperse formaldehyde in the environment of a hair salon, possibly exposing the consumer and the hair professional technician to hazardous airborne amounts of formaldehyde. A laboratory room was equipped with three air pumps located at three locations: close to the heads of a mannequin, nearby the hair technician and the whole volume of the room. Pumps were connected to cartridges apt at trapping airborne formaldehyde. The latter was further quantified through an HPLC procedure.As compared to hair treatments free from formaldehyde that do not modify the airborne formaldehyde levels, products with a high concentration of formaldehyde (1.7% and 9.3%) disperse this compound in the environment to a high and hazardous concentration, detrimental to both consumer and hair professional. The brushing procedure on the hair led to a much higher dispersion of airborne formaldehyde than the hair straightening/ironing technique. To conclude, the use of hair treatments that contain high and illegal amounts of formaldehyde creates a hazardous environment to all people present within a hair salon.Implications: This methodology adopted here might be used to evaluate during conception phase the level of Formaldehyde release and be used as part of safety data for the registration. However, the present work also strongly promotes the adoption of electronic detectors (commercially available) that continuously record the aerial concentration of Formaldehyde, when dealing with hair styling products that contain legal or illegal (> 0.2%w/w) content of Formaldehyde These detectors not only cover an adequate and realistic range of aerial Formaldehyde but can be used and transported at different locations of a given space. Such a cautious measure comes from common sense as it relates to the health status of consumers and operators present in a hair salon environment.