As a publicly-traded for-profit entity, their number one goal is to make money. Safety precautions are costly, and their motivation will largely stop after meeting regulations (to the effect that they are enforced). It looks like the divers found some violations, and hopefully Enbridge will fix that. Regulations are costly for business, but a lack of enforceable regulations can be very costly for the public. Of course, there should be a balance. Here it looks like the public is shouldering a lot of risk on Enbridge's behalf. Sometimes management can do right by the public, making sure that even unenforced regulations are met. Enbridge's history suggests that they don't have that kind of management.
I would hazard a guess that attempts to put those regulations in place would be thwarted by politicians who accept lobbyist money. For a while now, I've felt compelled to work for the EPA. But when I continuously hear how they aren't allowed regulate one thing after another due to outrageous laws, it makes me think that a more radical group like Earth First! might be a more fruitful option.