Carcinogenic risks in stationery products may vary depending on the type of chemicals and materials used. But some common risks are:

1. **Phthalates**: Chemicals that can be found in some plastic stationery products, especially erasers, pencil cases, and some other plastic products. Phthalates are known as hormone disruptors and can cause health problems with prolonged exposure.

2. **Heavy Metals**: Heavy metals such as lead, cadmium and mercury found in some stationery products, especially cheap colored pencils, paints, and some metal items can be hazardous to health.

3. **Some Solvents**: Solvents found in chalk, adhesives, markers and some inks can be carcinogenic under prolonged or intense exposure.

4. **BPA (Bisphenol A)**: May be found in some plastic products. BPA is a chemical that can affect the hormonal system and has been associated with cancer risk in some studies.

It is important to be aware of these risks and, if possible, to buy stationery products that do not contain carcinogenic substances and that have reliable certificates. In addition, training children not to put their stationery in their mouth provides an extra protection against such risks.

Finally, it is also important to carefully read the labels of the products and be knowledgeable about the product. If you have concerns about a particular product, it is best to contact the manufacturer or choose not to use the product.