A moving truck that was stopped by security at a gate to Hanscom Air Force Base contained potentially hazardous material, and the area around the gate has been evacuated, State Police said.

State Police were notified at about 9:45 a.m. that the truck had been stopped at Gate 1 of the base, State Police said in a statement.

“A standard screening of the truck and its cargo revealed indicators of potentially hazardous material,” State Police said
https://www.boston.com/news/local-ne...nscom-air-base

Weasel Zippers has posted a few news tweets saying the materials have tested positive for explosive materials.

https://www.weaselzippers.us/347406-...tion-underway/