Police are investigating three different incidents involving greeting cards with an unidentified white powder inside mailed to businesses in the Greater Lawrence area.
Hazmat crews were on scene at a house in Brighton Saturday morning.
A gas leak forced an evacuation at a lab on the campus of MIT on Thursday.
A hazardous materials team responded to a brief incident at a state prison in Gardner.
Three workers were taken to the hospital on Tuesday after possibly being exposed to a hazardous chemical.
The state Department Of Transportation has decided that trucks carrying hazardous materials, including gasoline and heating oil, cannot travel through Boston between 6 a.m and 8 p.m.
Hazardous materials crews responded to Nashoba Regional High School in Bolton on Sunday.
Police say they found a man in a car on Maguire Road who said he ingested liquid cyanide.
A state official is now under investigation in an alleged scheme to steer lucrative contracts to a Malden hazardous waste company.
The mystery behind a hazardous materials scare Wednesday in Roxbury has been solved.