T he health and safety implications of fi fth-generation (5G) cellular-communication technology have been under scrutiny while the rollout is well underway worldwide. Advocates of 5G mobile technology hail 5G as a faster and more-secure technology than its predecessor 3G and 4G systems. The major enabling infrastructure uses millimeterwave (mm-wave) and phased-array technologies to achieve line-of-sight directivity, high data rates, and low latency. A central vulnerability or security threat is that it may allow spying on users. Nevertheless, this is a system architecture and technology or regulatory issue, but not a biological or health safety matter.