As luck would have it, I am taking my NY State Asbestos Supervisor Exam tomorrow. So, a little fresh knowledge that I can offer is that the statement "Marinite is not friable" is ill-informed. Any and all ACM can become friable. The definition of friable is the condition of a material that can be crushed by hand pressure. Any damaged ACM must be repaired, enclosed, encapsulated or removed by qualified workers who have current state certification. The custodial staff should be trained in operation and maintenance of ACM.
Although the first response seems like BS to me, it sounds like they came around and are doing the right thing. But, whenever you enter the area in the future, you should make a careful inspection of the material and report any damage to your IH.
Also, be careful about brand-names such as Marinite or Garlock. Many people confuse the brand-name with the content of the material. Although neither of these is currently manufactured with asbestos, both were in the past. So, a current MSDS may not be a reliable source of information about materials used in construction of an old nuclear plant (or any other facility for that matter).