CHAPTER VI

Engineer and Chemical Operations

Starting with the construction of the D. S. [double-single] Bailey Bridge at Ben Cat on 21 Dec 66, and ending with the demolition of the tunnel complexes on 26 Jan 67, Operation Cedar Falls was without exception the most significant combat engineering operation of the war to date. New concepts of jungle warfare using dozers to open heretofore inviolable VC strongholds; the emergence of a new 'Secret Weapon,' the dozer infantry teams; and combined acetylene and HE (High Explosive) tunnel demolitions; all have proven unique, successful, and of tremendous value to future operations. Operations Niagara Falls and Cedar Falls introduced massive jungle clearing in conjunction with tactical infantry operation on a scale never attempted before. A total of 54 bulldozers were under the OPCON (Operation Control) of the 1st Engineer Battalion. . . .

So spoke Lieutenant Colonel Joseph M. Kiernan, Jr., commanding officer of the 1st Engineer Battalion, in summarizing engineer operations during CEDAR FALLS.

Engineer and chemical operations during CEDAR FALLS involved innovative techniques as well as others more familiar and routine. Engineer forces were assigned normal missions such as the construction of a Bigfoot Bailey bridge before the operation to facilitate the movement of the 11th Armored Cavalry Regiment into the Iron Triangle and the clearing and construction of landing zones, roads, and support areas. More unusual projects included the clearing and destruction of enemy underground complexes during search and destroy operations, the stripping of acres of jungle, and the establishment of a waterborne seal at the confluence of the Saigon and Thi Tinh Rivers to prevent enemy escape. The dropping of CS munitions from helicopters and the destruction of rice were entrusted to the chemical personnel.

The engineer-chemical task force for CEDAR FALLS had under Colonel Kiernan's command some six hundred men from the 1st Engineer Battalion, flame-thrower platoons from the 1st Squadron, 4th Cavalry, the 'tunnel rats' (tunnel exploration and demolition crews) from the 242d Chemical Detachment, and approximately three hundred engineers from the 79th Engineer Group. This last complement consisted of men and equipment drawn from four engineer battalions, a light equipment company, and a maintenance detachment.