One executive displayed a children's pink helmet that she said would be increasingly unavailable if tariffs were raised, while another pleaded, "Help me keep my company alive."

A third said that average Americans would pay more to tend to their gardens with price increases on tools such as leaf blowers.

Representatives from a broad cross-section of US businesses and industrial groups began to voice their concerns on Monday, the first of six days of public hearings on the impact of a fresh round of tariffs on Chinese products, with many saying that hefty duties harm American consumers, workers and businesses as well as the economy.

US President Donald Trump has directed the US trade representative to consider increasing the additional duty from 10 percent to 25 percent on $200 billion worth of Chinese imports, targeting thousands of consumer products ranging from chemicals to cosmetics.

The tariffs would be the same as those the US already has imposed on $34 billion in Chinese goods and on another $16 billion to be activated on Thursday.

Many executives testified on Monday that production of the Chinese imports to be targeted could not feasibly shift to the US.

Ross Bishop, president of BrightLine Bags, whose products are manufactured in China, was the first to testify before the USTR on Monday.

"We've made three specific and concerted attempts at getting our bags made in the US and have learned from each instance that our costs would triple compared to what we pay now, and the detailed quality isn't as good," Bishop said.

Already paying 17.6 percent duties, an additional 25 percent of tariffs will bring the company to "an absurd level of 42.6 percent", which has the "undeniable potential" to cripple his company, he said.

"Please help me not only keep my company alive, but actually help me grow my company so that we can continue making a real difference to the important field professionals that we touch every day," he said. "Do not let this ill-advised and harmful tariff see the light of day."

Joseph Cohen, CEO of Snow Joe LLC, said "significant harm" would be inflicted on US consumers and businesses without advancing the US administration's goal if a 25 percent or even 10 percent tariff were imposed on various consumer products offered by his company.

He requested the USTR exclude electric and cordless pressure washers, leaf blowers and vacuums, among other products on the target list.

"With no known US or significant third country supply source outside of China for the items impacted by the proposed tariffs, we have no choice but to rely on existing sources in China," Cohen said. "If tariffs are imposed, we will be unable to offset the impacts of these tariffs by shifting suppliers."

Cohen also said Snow Joe is not aware of "any instances of Chinese intellectual property theft" with respect to the products made in China for his company.

Thomas Cove, president and CEO of the Sports & Fitness Industry Association, said China remains a "vital and not easily replaceable link" in the industry's supply chain.

"Shifting manufacturing to other countries is simply not feasible in real time or at scale," Cove testified.

Higher prices following the potential tariff increases could threaten Americans' health, he said.

"We make products that keep people physically active and healthy," he said. According to the CDC, the average per capita health care spending for inactive Americans is $1,437 more per year than for active Americans.

"It makes no sense to drive up the price of products that otherwise contribute to lowering the national expenditure on health care," he said.

Jen Harned, president and general manager of Bell Sports in Illinois, a manufacturer of bicycles and motorcycle helmets, showed a children's helmet during her testimony, telling USTR officials that the tariffs on these products would "ultimately jeopardize the safety of ordinary Americans".

Harned said that skiers, motorcyclists and others would choose inferior products and "ignore safety laws".

Ying Wang in Washington contributed to this story.

Contact the writer at [email protected].