The significance of the Bureau of Mines approval of gas masks

Year:	1932
Document Type:	USBI
Issuing Agency:	U.S. Dept. of Commerce, Bureau of Mines,
SUDOC:	C 22.11:6665
Series:	Information circular / Bureau of Mines ;
Report Number:	6665
Subjects:	Gas masks
	Mine safety--Equipment and supplies
Link:	https://hdl.handle.net/2027/mdp.39015077564873