What substances are prohibited for licensees to use in performing cosmetology services?

The correct response highlights that MMA (methyl methacrylate) and razor-type shavers are prohibited substances in cosmetology services because they pose significant health risks. MMA is a type of acrylic used in nail products that can lead to severe allergic reactions and damage to the natural nail. It is known for its strong odor and potential to cause skin irritation and respiratory issues, making it a dangerous choice for both practitioners and clients when performing nail services.

Razor-type shavers, often used to create very thin layers of skin for aesthetic treatments, can lead to skin infections and other complications, particularly when proper hygiene practices are not followed. The use of such tools increases the risk of cutting the skin and introducing bacteria, which is why their usage is not permitted in professional settings.

In contrast, the other choices are not inherently harmful. Regular soap and water are essential for sanitation and hygiene practices. Medical-grade disinfectants are critical for ensuring a safe environment in beauty services, as they effectively kill pathogens. Organic substances can be safe and beneficial when used appropriately in cosmetic applications. Thus, the emphasis on the prohibition of MMA and razor-type shavers is paramount for maintaining safety standards in the cosmetology field.