The Saskatchewan government says an estimated 1.2 million litres of oil leaked from a Canadian Pacific Railway train that derailed near the hamlet of Guernsey last week.

That's less than the estimated 1.5 million litres that is believed to have leaked in a separate train derailment, also near Guernsey, last December.

But it's still five times the amount of oil spilled during the 2016 Husky Energy pipeline disaster near Maidstone, Sask.

The cause of both train derailments is under investigation by the Transportation Safety Board of Canada. The TSB has yet to issue its first update on the investigation into Thursday's crash.

The province said the estimated spill figure for Thursday's derailment came from CP.

"The amount of recovered oil [in Thursday's crash] is currently being determined and is complicated by the fact that a significant portion burned off during the incident," a spokesperson for the provincial government said Tuesday.

The oil caught fire in the crash and continued to burn into the next day.

"Fortunately, in both cases, the spill was fully contained to the railway and highway ditches and impacted a relatively small area."

Frozen ground likely helped reduce the risk of contaminants penetrating too deeply into the ground, the spokesperson said.

Tank manufacturer monitoring situation

Thursday's train crash happened shortly after 6:15 a.m. CST. Thirty-two cars jumped the tracks west of Guernsey, a small hamlet located 116 kilometres east of Saskatoon.

ConocoPhillips said the train was carrying a type of diluted bitumen called Surmont Heavy DilBit (SHD).

At least 12 of the train cars caught fire, according to the Saskatchewan Public Safety Agency. Drone footage showed at least two large pools of spilled oil staining the ground next to the railway.

There have been no reports of injuries after a train derailed near a Saskatchewan hamlet. Emergency response says 12 of the 31 cars that derailed are on fire. 0:33

CP has confirmed the train was using a newly built type of tank car meant to have better puncture resistance than the ones that exploded in the deadly Lac-Mégantic, Que., train derailment in 2013.

Trinity Rail, the Texas-based company that manufactured the train cars involved in Thursday's derailment, said Tuesday it's monitoring the situation.

"Trinity is committed to the safety of its employees, subcontractors, customers and community as a matter of top priority," a company spokesperson said.

Cleanup to take several months

According to the province, CP has hired contractors and environmental consultants to develop a remediation plan.

It's not clear how much soil was impacted.

"It is not known exactly how long the cleanup will take to complete but can be expected to take up to several months," the government spokesperson said.

Transport Canada, which regulates Canada's rail industry, said Tuesday it has appointed a minister's observer to keep the minister informed of the TSB's investigation.

"Transport Canada has also sent remedial measures specialists, inspectors and tank car specialists to the site to verify compliance with the Transportation of Dangerous Goods Act and regulations, provide advice to the TSB and examine the tank cars," a spokesperson said.