Oil spill between Milwaukee and Madison has caused concern. What we know and don’t know.

On Dec. 13, it was publicly learned that Enbridge Energy’s Line 6 spilled nearly 70,000 gallons in the Town of Oakland in Jefferson County.

Here’s what we know, and what we don’t know.

What did Enbridge initially report?

Enbridge first issued a report to the Wisconsin Department of Natural Resources on Nov. 11, stating that two gallons of crude oil spilled at its Cambridge Station due to a faulty connection. On Nov. 14, Enbridge revised the estimated spill to 126 gallons. A month later, on Dec. 13, that number was revised again, to 69,300.

Why didn’t the public know the extent of the spill right away?

In Wisconsin, neither the responsible party nor the DNR are required to inform the public of an oil spill, Nobile said, unless there is imminent risk to the public, according to Trevor Nobile, a field operations director with the DNR’s Remediation and Redevelopment program.

What is frustrating to people concerned about oil spills?

There are concerns about the time it took to report the spill, and the credibility of the initial reporting.

Further, the DNR announced it had approved a controversial Enbridge project — the reroute of Line 5 in northern Wisconsin three days after Enbridge first reported the Town of Oakland spill. Enbridge has proposed to reroute Line 5 around the Bad River Band of Lake Superior Chippewa’s land. To some, that showed a lack of overall concern about spills.

What don’t we know yet?

The ultimate size of the spill isn’t necessarily known yet. It may change yet again as Enbridge continues to take samples.

This article originally appeared on Milwaukee Journal Sentinel: Enbridge oil spill raises safety concerns. What we know, don’t know.