The battle focuses on a company called A-1 Storage, which is located at the end of a residential street.
Inside the mini storage units are dozens and dozens of pot plants growing in water and artificial light, but that's not what has neighbors so upset.
Instead, they say it's the increased vehicle traffic that has them worried.
"I'm concerned about the safety of my kids," said neighbor Sharilyn Matthews. "They're going to be forty people coming and going on this street. And who knows if they're impaired, you know."
Matthews is one of the Sedro-Woolley residents fighting to keep A-1's plan to expand.
Company owner Tom Swett already rents out 26 storage units where medical marijuana patients are legally growing their own plants, and a hearing officer recently approved a permit to add another 14 spaces.
A man named Matthew said he grows marijuana in one of the units. He didn't want his last name used, but said he severely injured his spine three years ago and that marijuana is the only pain reliever he can tolerate.
He said growing pot at a secure storage unit is far safer than growing it at his house, where robbers or police could show up.
"Someone could kick in my door, for either their own profit or to enforce a regulation. And that's something I would feel real remiss for if I subjected my children to that," he said.
Neighbors say they remember hearing that argument at the public hearings for the facilities, but not everyone agrees with it.
"And that's when I stood up and said, 'What about my kids on this block?'" Matthews said.
A-1's owner said his customers don't sell the marijuana, need to get approval from a doctor and must abide by all state laws to get a storage unit.
That's not good enough for neighbors, who say they will fight the expansion.