A significant fuel spill caused when a tanker truck crashed northwest of Toronto has been contained, police said Tuesday as crews continued to clean up the area.

The truck lost control around 2:30 a.m. in Caledon, Ont., and the back tanker of two being hauled in tandem fell over in the crash and began leaking, said the Ontario Provincial Police.

Const. Stephanie Hammond said the tanker had dumped about 23,000 litres of gasoline, but the leak had been contained. She said another 10,000 litres remained in the overturned tank and was being pumped into a new tanker. 

The fuel had gone into nearby ditches and a catch basin, she said.

"This is a significant fuel spill," Hammond said. "We have a pumper truck down there pumping out what fuel they can visibly see as well as digging out the ditches to remove the soil that has got the fuel in it as well."

Originally, authorities thought there was no threat to nearby wetlands and the Humber River, but rainfall wreaked havoc with the cleanup, Hammond said.

"There is a potential for the fuel 芒鈧珺次元官网网址� because of the rain 芒鈧珺次元官网网址� to get into the Humber River and we've got all the tributaries and all the wetlands down there as well," Hammond said. 

The spill occurred near the Glen Haffy Conservation Area, home to wetlands and a fish hatchery that raises rainbow trout, according to the Toronto and Region Conservation Authority.

The Ministry of the Environment and Climate Change was also on the scene of the crash.

An environmental contractor was also helping out, said ministry spokesman Gary Wheeler.

"Contractors used sandbags and absorbent booms to contain and prevent the spill from spreading," Wheeler said.

"A vacuum truck is being used to clean out the catch basins."

Hammond said speed doesn't seem to be a factor in the crash, but said it's unclear how the driver lost control.

The OPP said late Tuesday that Highway 9 from Airport Road to Glen Haffy Road had been reopened.

Liam Casey, The Canadian Press