HUDSON — As the owner of a small but thriving Internet sales business, Travis Adams fears for his company's future should the Marketplace Fairness Act come to fruition.

The Internet sales tax legislation, which recently was passed by the Senate, would force online retailers like Adams to collect sales taxes on behalf of more than 9,000 taxing jurisdictions nationwide.

Adams began his business, Whaddy.com, in Nashua in 2011. The company, which moved to Executive Drive in Hudson last summer, sells overstock and customer return items online via retail sites like eBay and Amazon.

Business has been booming, Adams said; he's hoping to add 10 positions to his six-person staff within the coming year.

"We need more hands to move things quicker," he said.

But should the Marketplace Fairness Act become law, Adams said his most pressing need would be to hire a full-time accountant.

Right now, Adams contracts the services of part-time bookkeeper Kathleen Alves, an accountant with Medaglia & Co. in Nashua.

Alves said the new legislation could cost Whaddy "between $15,000 to $75,000 per year" in additional expenses, including salary for a full-time staff accountant.

"A new tax rule would definitely slow us down," Adams said. "Hiring an accountant would likely take away several pairs of hand that would have been bringing in revenue."

This past March, Adams traveled to Washington, D.C., where he shared his concerns with Congresswoman Annie Kuster.

The Democrat visited the Hudson warehouse Tuesday morning. She toured the facility, chatted with employees and shared the latest information on the pending legislation.

A vocal opponent of the Marketplace Fairness Act, Kuster said the legislation would have a devastating impact on Granite State businesses, particularly those that conduct most of their business online.

"We're a live free or die state, and we're known as a no sales tax state," the congresswoman said. "This (legislation) would make a not-so-level playing field."

Kuster has voiced disapproval of the measure alongside fellow Democrat U.S. Rep. Carol Shea Porter. She said she's feeling somewhat hopeful, since the House appears "much more resistant" to the legislation than the Senate. Sens. Kelly Ayotte, R-N.H., and Jeanne Shaheen, D-N.H., both voted against the bill.

"We're trying to express the truth about this, that this would be enormously burdensome for businesses (like Whaddy)," Kuster said. "It goes against everything we're working toward — an environment for job creation, where small businesses can continue to grow."