Three years after New Jersey's medical marijuana law was enacted, only one of the six authorized alternative treatment centers is dispensing the pot to qualified patients.

More of them are in the process of getting state approval.

While a center in Montclair in North Jersey has been open since December, state Health Commissioner Mary O'Dowd says a second facility located in Egg Harbor is awaiting a building inspection by the state Health Department before it can begin serving patients.

"Some of the delays in that process were due to the fact that they provided us regular and routine changes and updates as to the individuals that were involved as well as the organizations that were investing in it," she said Wednesday. "I think that was a challenge for them and caused some delay on their end."

O'Dowd says the state has started to review the required paperwork from three other alternative treatment centers. She would not estimate when they'll be able to open.

One of the main challenges in getting the centers up and running is to make sure the program withstands federal scrutiny, she said.

"As we have moved towards implementation the federal government has taken action against these types of businesses in other states," O'Dowd said. "So that remains a concern and an element of our planning each and every day."