Broadband cards and network security

One of the directors in my company just got a broadband card for his work laptop. I have not dealt with these cards before. From a LAN security point of view are there risks and if so what are some fixes?
For example, if he is logged onto our LAN via the wireless card in his laptop and our wireless access point is there any risk of compromise via his broadband connection to the internet?

Thanks for any info!!