Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 159, § 102

No railroad corporation or railway company or any officer or employee thereof shall use or deposit a torpedo or other explosive upon or near the tracks of any railroad or railway for the purpose of signaling or otherwise, unless there is plainly and conspicuously stamped or otherwise permanently marked thereon in a manner approved by the department a word or words indicating that such torpedo or other explosive is dangerous.