Nothing in my post said that the state would allow your grandchildren to continue living in the street.
Nothing in my post said that the state would allow your grandchildren's condition to go uninvestigated or unresolved.
I did say that a report to CPS would not necessarily result in you getting custody of your grandchildren - it is possible that CPS would place the children in foster care.
Me telling you anything short of this would simply be a lie and a disservice to you.
I also told you that if you want to be more certain about the placement of your grandchildren - meaning you want to ensure that they are placed with you (and more importantly, that you want to be given decision making powers for them), you will want to apply for a guardianship. http://oregonlawhelp.org/resource/guardianships-for-children?ref=tRCCY
I further posted that this is a significant shift in rights - if you want to be successful, hire a lawyer. Some grandparents have been successful doing this on their own, but if your grandchildren's parent plans on fighting you on this (based on the facts as you have posted them - both initially and in your follow up - I would prepare for a fight if I were you), get a lawyer - this is not easily done (either procedurally or legally).
It is possible to gain a guardianship over children that are living in a dangerous environment. Being a relative of the child increases your chances. However, being represented by counsel is important given the legal rights, standards, and procedures involved.
Again, I am very sorry to learn of your grandchildren's situation, I am certain it is very painful, but the above procedure is the way to resolve it.