As you are probably aware, Blue Cross Blue Shield no longer offers ACA subsidized insurance in the Knoxville or other major Tennessee metro areas, or any other individual (i.e. non-employee provided) plans off the exchange. Humana is now the only company offering Knoxville area plans on the healthcare.gov exchange.

Looking at the healthcare.gov estimator for the Humana bronze and silver plans (the only two offered), there are generous ACA subsidies for those who qualify resulting in low monthly premiums for basic coverage. (High deductibles still apply, like most insurance these days.) The Knoxvile PPO network has good coverage among area providers.

But, there's a huge catch. Neither Humana plan has an out-of-pocket limit on out-of-network coverage. There is an out-of-pocket limit of $6500 if you are in-network. but there is no limit for out-of-network. And, there is no out-of-state or national in-network coverage with these plans. We called Humana to verify if this was correct. It is.

This means that if you are traveling and have a serious accident or medical event and go to an out-of-network hospital, you are responsible for the entire cost (or possibly the 80% out-of-network co-insurance, not clear). So if you rack up $100,000 in medical bills, the out-of-pocket limit doesn't apply and you are responsible for the full $100,000 (or $80,000 of it, not clear), as opposed to $6500 if it happened in-network. It's like having no insurance at all. (It appears that ACA requires ER visits to be covered as in-network, but if you are admitted all bets are off.)

Blue Cross Blue Shield plans offered on the exchange for 2016 had an out-of-network, out-of-pocket limit. These plans are no longer available. BCBS group plans (i.e. employer provided plans) still have the limit.

It's unfortunate that plans with no out-of-pocket limits are the only ACA subsidized plans available in Knoxville. It's surprising that such plans are even legal. But they are.

MORE: PPO Plans Remove Out-Of-Network Cost Limits, A Costly Trap For Consumers