O perigo é que pode haver uma reação química entre os componentes da tinta do marcador e a superfície do disco. Alguns marcadores "permanentes" são bastante agressivos e, embora o dano não seja imediato, isso pode acontecer com o tempo. Conselho de Biblioteconomia e Recursos de Informação diz em seu relatório :
Numerous CD vendors have noted that the thin protective lacquer coating can deteriorate from contact with certain solvents in markers. To eliminate the risk, water-based markers are recommended for CD labeling. As a solvent, alcohol is generally less damaging than xylene and toluene, which are common in aromatic solvent-based markers. According to anecdotal reports, alcohol-based markers can be used to label CDs without causing performance problems. However, there are no explicit lab test results to show what effect solvents in markers have on different CDs or DVDs, particularly over the long term.
Com relação aos marcadores Sharpie especificamente, isso é o que Perguntas frequentes da Sharpie diz:
Newell Rubbermaid has used Sharpie markers on CDs for years and we have never experienced a problem. We do not believe that the Sharpie ink can affect these CDs, however we have not performed any long-term laboratory testing to verify this. We have spoken to many major CD manufacturers about this issue. They use the Sharpie markers on CDs internally as well, and do not believe that the Sharpie ink will cause any harm to their products.