Environmental - Certifying SPCC Plans for other states

New Environmental PE here with what should be a simple question. Do you need to have a license in a state in order to certify a Spill Prevention, Control, and Countermeasures (SPCC) Plan in that state? Done a fair amount of googling and have only been able to find the following:

EPA seems to not care: https://emergencymanagement.zendesk.com/hc/en-us/articles/212085097-PE-certifying-an-SPCC-plan-in-a-different-state

General opinion is that States will care: http://www.eng-tips.com/viewthread.cfm?qid=295961

Is it safe to assume all states have a rule which says that only PEs licensed in their state can practice in their state? Is there a go-to resource if it varies from state to state?

Thanks for the help everybody!

Q#1: Not that I've heard. If there is, it's very rare. Generally speaking, engineering is required when design(calc) and implementation(construction) phases occurred. After that, it's all operation and maintenance (O&M); thus no engineering certification is required. SPCC is like an O&M activity. 

side note: Environmental is an oddball engineering discipline when it comes to RCRA or NPDES regs because ultimately it's more of a scientific discipline than application of engineering. These kind of stuff are taken over by the Environmental Scientist degree holders or geoscientists. 

Q#2: That's the idea and it's a common thing for many other professions (accounting, doctors, dentist, surveyors, etc...) to only provide the professional services if you're registered in that state. 

Hmm, I know we had a PE in our office who used to do SPCC plans and would stamp the reports...I don't believe he was licensed in the states his sites were in, though. I'd be curious to hear what others have to say.