Sen. Jon Tester said last week he’s concerned about a bill being considered by Congress that would require states with no sales tax like Montana to collect it for states that have a sales tax.

Tester said in a conference call he would oppose any sort of measure like that but noted it could come up soon. He was worried there may be enough votes to get the measure passed.

The bill would require Montana companies to collect the tax if a consumer from a state that has a sales tax, like Florida, buys something from Montana in an online purchase.

Tester called the measure onerous for Montana businesses. Montana is one of only five states in the U.S. that do not have a general sales tax. The other four are Alaska, Delaware, New Hampshire and Oregon.

“We don’t want to collect sales tax for someone else,” Tester said.

Tester also talked about his vote for expanded background checks for gun purchases.

“This wasn’t additional gun control,” he said. “This was background checks.”

He said the amendment, which failed in the Senate last week, would have done more to keep guns out of the hands of criminal and mentally ill people.

“This bill made sure that people who don’t use guns properly don’t have access,” he said.

The bill would have allowed gun sales to family members and friends without a background check.