Which of the following is classified as Category I non-friable materials?

Category I non-friable materials are defined as asbestos-containing materials that are firmly bound in a solid matrix, meaning they are unlikely to release asbestos fibers into the air under normal handling conditions. Gaskets fall into this category because they typically consist of solid materials where asbestos is not easily disturbed or crumbled.

In contrast, fibrous insulation is usually considered friable, meaning it can release fibers more easily when disturbed. Concrete and gypsum board, while they can contain asbestos, are not classified as Category I non-friable materials since the asbestos presented could possibly be more accessible or pose a risk in certain conditions. Thus, gaskets are recognized specifically as a prime example of Category I non-friable materials due to their robust structure.