Which of the following products is known to contain PCBs?

Thermal insulation is known to contain PCBs (Polychlorinated Biphenyls), primarily in older materials used before they were banned. PCBs were commonly utilized in various building materials, including certain types of thermal insulation, because of their chemical stability and insulating properties. These substances are hazardous and can pose health risks, leading to stringent regulations on their use and disposal.

In contrast, glass bottles, bamboo products, and wooden furniture do not contain PCBs. Glass is made from silica and does not typically involve PCB components. Bamboo products are generally natural and organic, while wooden furniture does not inherently contain PCBs, unless treated with old chemical preservatives that might have included them. Therefore, thermal insulation is the correct answer regarding the presence of PCBs.