Gunfire is dangerously loud. Most handguns and rifles produce peak noise levels over 150 decibels — noisier than a jet engine at takeoff, higher than the maximum threshold set by the Occupational Safety and Health Administration for what can cause permanent hearing damage.

The House Natural Resource Committee was scheduled to hold a hearing on whether the government should continue to tightly regulate the sale of devices that make guns somewhat less loud on Wednesday morning. The hearing was postponed after Louisiana Republican Steve Scalise, who supports silencer deregulation, and four others were shot at a baseball field in Alexandria, Virginia, Wednesday morning.

The measure up for consideration is the Sportsmen’s Heritage and Recreational Enhancement Act (SHARE), sponsored by South Carolina Republican Jeff Duncan. The bill would also weaken the requirements for transporting a firearm across state lines and make it easier to purchase armor-piercing bullets.

The SHARE Act would remove suppressors — also known as silencers — from a list of items regulated by the 1934 National Firearms Act, which also includes machine guns, short-barreled rifles, and destructive devices. Currently, suppressor purchases require an application to the Bureau of Alcohol, Tobacco, Firearms, and Explosives, the payment of a $200 tax (a fee which has not increased since 1934, when it was equivalent to $3,500 in today’s dollar) and completion of a background check — a process that can last up to a year.

Despite the hassle and cost, suppressor sales are booming. According to the ATF, the number of registered suppressors more than tripled from 285,087 in 2010 to 902,805 in 2016.

Hunting and gun-rights groups, along with their allied lawmakers, say the government regulations are an unnecessary, costly burden on law-abiding gun owners who want to protect against hearing loss. Opponents say quieter guns could be used by criminals or terrorists to kill more easily without detection.

Here’s what else you need to know about the debate over quieter firearms.

Who supports silencer deregulation?

Prominent gun-industry supporters, including the National Shooting Sports Foundation and the National Rifle Association, are pushing the deregulation of suppressors. Both organizations, and many of their gun-rights peers, advocate for suppressors on the basis that they will protect the hearing of recreational shooters and hunters.

Last month, the NRA invited newspaper reporters to observe suppressors for themselves. Chris Cox, the organization’s top lobbyist, was on hand.

“When I take my son out and teach him how to shoot, I’m supposed to try to make that gun as loud as possible? Or am I supposed to do everything I can to try to protect his hearing?” Cox said, as reported by USA Today. “The joke is, you go to any hunting club and ask one of the older members a question and, the answer is always, ‘Huh? What?’”

Gun-rights advocates also point out that suppressors do not completely silence firearms.

“It’s important for people to see it firsthand, so they can understand fact versus fiction,” Cox told reporters. “A lot of people think that what you see in the movies is actually the reality as it relates to suppressors. They’re not silent.”

In March, WBEZ, Chicago’s public radio station, recorded sound clips of multiple types of guns fired with and without suppressors. The difference is audible.

Suppressors also have supporters close to the White House. Donald Trump Jr., the president’s eldest son and a shooting enthusiast who’s frequently been photographed on hunting expeditions, filmed an eight-minute-long promotional video for SilencerCo, the nation’s leading suppressor manufacturer. The company’s chief executive officer was invited to Trump’s inauguration.

Representative Duncan introduced the SHARE Act with Texas Republican John Carter. Duncan is also the sponsor of separate suppressor-deregulation legislation known as the Hearing Protection Act, which has 148 co-sponsors.

Knox Williams, the president of the American Suppressor Association, says the bill would “have a tremendous impact on both the safety of hunting and recreational shooting” — and would also lead to the “expansion of the market place.”

How effective are silencers in reducing the risk of gunshot-induced hearing loss?

The noise output of a firearm depends on a variety of factors, but many models produce peak decibel noise levels of 150-163 decibels. According to OSHA, any noise over 140 decibels can cause hearing damage. Research conducted by William Murphy and Scott Brueck at the National Institute for Occupational Safety and Health found that suppressors reduce the noise of a gunshot by 15 to 30 decibels.

The popularity of suppressors is relatively new, and as a result there is scant research on their efficacy.

In 2011, Brueck lead a team of researchers from the Centers for Disease Control and Prevention in a study of noise and lead exposure at an outdoor firing range in California. Over a three-day observation period, the researchers recorded noise levels that exceeded 160 decibels. The authors reported that the “only potentially effective noise control method to reduce students’ or instructors’ noise exposure from gunfire is through the use of noise suppressors that can be attached to the end of the gun barrel.”

In the report’s conclusion, the researchers advised that range patrons and employees should wear double hearing protection while exposed to gunfire, the range should institute a hearing-conservation program, and that instructors should have yearly hearing evaluations.

An American Silencer Association-funded study in 2015 tested various silencers on short-barreled AR-15 rifles. Dr. Colleen Le Prell, the study’s co-author and a hearing-loss-prevention specialist at the University of Texas at Dallas, said that unsuppressed gunshot noises are “incredibly hazardous.” She recommends using other means of hearing protection along with silencers.

“From the AR-15 in particular, even with the suppressor, sound levels are still dangerously high,” she added. Unsuppressed, the guns can generate noises up to 190 decibels, Le Prell said.

Why do people oppose the bill?

Gun-reform activists said other measures — like expanding background checks or stopping gun sales to people on terror-watch lists — are far more important than deregulating silencers.

“Here we are talking about this when 93 percent of Americans want to know why lawmakers aren’t talking about how to keep guns out of the hands of felons, domestic abusers, or fugitives,” said Brendan Kelly, a spokesman for the Brady Campaign To Prevent Gun Violence, citing a Quinnipiac University poll that 93 percent of Americans support background checks for all buyers.

Others stressed the importance of the gun’s actual blast as a safety measure. In a Washington Post op-ed, Robert J. Spitzer, a political scientist who’s written extensively on gun politics, noted that the loud noise made by a gunshot helps passersby recognize a hunter or a threat.

Spitzer argues that the reason silencers are rarely connected to crimes is because they are so tightly regulated. In 2015, the ATF traced traced 125 registered silencers to crime; that was up from 85 in 2014.

“The proliferation of silencers would introduce a menacing new threat to our nation’s communities and our law enforcement professionals,” said Sean Simons, deputy press secretary at Americans for Responsible Solutions.

During a 2015 hearing on silencer deregulation in the Minnesota legislature, the State Police association opposed the bill, saying more silencers would make it more difficult for law enforcement to detect gunshots — both for individual officers and for gunshot-detection technology like ShotSpotter — and owning the accessories would put gun owners at risk of theft.

If Congress passes the silencer deregulation, what’s next?

President Trump would likely sign the bill into law — and it might open doors for ever-looser silencer laws. The next legislative priority for Waldron, the SilencerCo CEO, is the Suppressor Export Act, which would allow American manufacturers to sell their wares to foreign customers.