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It was not clear whether professional handling was needed for the chemicals, but a local official said many riverside residents "had experience in salvage."
Soldiers and emergency workers stationed at eight points on the waterways in Jilin Province have worked around the clock since late Wednesday to collect the barrels before the torrents carry them further down the Songhua River into neighboring Heilongjiang Province.
At one point, where boats were chained together across the river, engineers used four cranes to remove debris before soldiers and experts on boats used long poles and steel nets to retrieve the barrels.
Heilongjiang on Friday also sent soldiers and workers to six points on the lower reaches of the river as water resources experts predicted the flow might carry the first barrels into the province late Friday.
However, helicopter spotters who have been tracking the barrels have lost sight of some of them. Experts fear they may have sunk into the river -- making their retrieval more difficult.
A video posted on Chinese web portal Sina.com Thursday showed a barrel catching fire and exploding on the river's surface.
Of the 3,000 chemical-filled barrels, about 2,500 contain trimethyl chloro silicane -- a colorless flammable liquid -- while 500 contain hexamethyl disilazane, also a colorless liquid, officials earlier said.
"The chemical will not cause havoc on the river unless a large number of containers are damaged at one time," said Sun Lili, deputy general engineer with the Design and Research Institute of Petrochemical Technology in Jilin Province.