The AR oil spill shows what happens when infrastructure is allowed to rot and fail - and that the companies have made a cost-benefit analysis that they’d rather them fail and fix individual sections than require the more costly rebuilding to modern standards.

But it also means that spills can occur anywhere along the line and damage the local ecosystems pretty badly. This is a relatively small spill, but one that has chased local homeowners from their homes and damaged their property pretty thoroughly.

It can contaminate local water sources, and make homes uninhabitable and increase risk of illness.

Keystone may be built to modern standards, which reduce risks, but it’s not risk free, and the tar sands petroleum product is of a kind that makes pipeline failures more likely and cleanup more difficult.