"They're not even a year into their grieving and this really triggers it," he said of the family of Linda Goldbloom, who died August 29 of "acute intracranial hemorrhage due to history of blunt force trauma" after being hit in the head by a ball four days earlier.

Zlotnick also heard from the father of a 1-year-old girl who suffered multiple facial fractures at Yankee Stadium two years ago. A 106-mph line drive into the seats seared an imprint of the ball's seams on her forehead. The incident and others spurred Major League Baseball to order all 30 teams to extend netting to the far end of the dugout.

"I used to say what's it going to take -- a fan to die before major league owners and the commissioner finally do something?" Zlotnick said.

"What will compel them to ... extend the netting down the line? Well, of course, last year a fan died and they said nothing and, up until now, they've done nothing and now this poor little girl got hurt."

Zlotnick himself suffered an orbital blowout fracture, a broken cheekbone, lacerations and a detached eye tendon from a foul ball at Yankee Stadium nearly eight years ago. He would not have been protected by extending the netting to the end of the dugout. He was with his son in the right field seats.

The girl who was struck on Wednesday night was sitting beyond the far end of the third-base dugout, apparently beyond the netting. Cubs outfielder Albert Almora Jr., who hit the ball, appeared distraught moments later. He threw his hands behind his head and knelt in shock.

Study: Foul balls hurt about 1,750 fans each year

Cubs outfielder Albert Almora Jr. is consoled after he hit a foul ball that struck a fan.

"For fans like me who have been injured and for their families, it's like a reliving of the trauma -- another kid in the ballpark carried out on a stretcher," said Zlotnick, who has become an advocate for extending protective netting.

Injuries to fans at ballparks have become increasingly common, said Nathaniel Grow, an associate professor of business law and ethics at Indiana University in Bloomington.

About 1,750 fans are hurt each year by foul balls at MLB games, citing an analysis by Bloomberg, said a study Grow and another academic published last year in the William & Mary Law Review

"This equates to a rate of roughly two injuries per every three games, making a fan injury from a foul ball a more common occurrence than a batter being hit by a pitch," the study said.

The girl who was struck on Wednesday was taken to a hospital. Her condition was not available.

MLB called the incident "extremely upsetting" and implied it would continue examining the issue of fan safety.

"Clubs have significantly expanded netting and their inventory of protected seats in recent years. With last night's event in mind, we will continue our efforts on this important issue," MLB said in a statement Thursday.

'Baseball rule' immunizes MLB teams from liability

For more than 100 years, a legal doctrine known as the "Baseball Rule" has generally immunized big-league teams from liability when fans are hit by balls or bats, Grow said. He has joined others in calling for its abolition on grounds the game was dramatically different when the rule was adopted in 1913.

MLB and foul balls 1,750 -- The number of fans hurt each year by foul balls 100 to 110 mph -- The speeds at which baseballs enter the stands $8,000 to $12,000 -- The cost of protective netting per 60 feet $10 billion -- MLB's gross revenue for 2018

"The current rule is that teams don't have to pay for any of these injuries and fans assume the risks by agreeing to sit in the stadium," he told CNN.

Teams have little incentive to take added measures to protect fans because of the absence of liability, Grow said. Courts have consistently held that pro baseball teams are not liable as long as they take minimal precautions to protect fans.

"It made more sense back then when balls were hit slower, there was more space between the seats and the playing field," Grow said. "Times have changed ... but the law still hasn't budged too much."

The study, "The Faulty Law and Economics of the 'Baseball Rule,'" said fans today often sit more than 20% closer to home plate than they did throughout most of the 20th century. This, combined with balls being hit into the stands by bigger and stronger athletes, substantially reduces the reaction time of fans.

"Indeed, in some cases it may now be virtually impossible for spectators to react in time to protect themselves," the authors wrote.

The study found that 21 of 30 major-league stadiums were built since 1992, with many retro-style ballparks featuring seats much closer to the field. The authors wrote that baseballs enter the stands at speeds of 100 to 110 mph.

Professional-grade netting would be relatively cheap -- at $8,000 to $12,000 per 60 feet, or as the authors wrote, "a drop in the bucket" -- for a $10 billion a year industry.

An MLB spokesman did not directly respond when asked about the findings, beyond referring a reporter to its earlier statement.

Advocate proposes an MLB compensation fund

In 2018, Major League Baseball announced that all 30 ballparks were extending protective netting to at least the far ends of both dugouts -- that is, the ends farthest from home plate -- intending to enhance fans' safety.

The move came after high-profile incidents in which batted balls struck fans -- including the girl struck at Yankee Stadium in September 2017 and a man who was blinded in one eye by a foul ball during a game at the Cubs' Wrigley Field a month earlier.

The clubs' move last year to extend nets to the dugouts' far ends went beyond what MLB recommended in December 2015. Then, the commissioner's office encouraged teams to shield field-level seats up to the dugout ends closest to home plate.

At the time, Commissioner Rob Manfred said the recommendation tried to "balance the need for an adequate number of seating options with our desire to preserve the interactive pregame and in-game fan experience that often centers around the dugouts, where fans can catch foul balls, see their favorite player up close and, if they are lucky, catch a tossed ball or other souvenir."

Some teams extend their netting beyond the dugouts' far ends.

Zlotnick, the New York real estate developer who sustained permanent eye damage from a foul ball, remains in touch with a growing number of fans injured in recent years.

"We don't get any protection in the courts," he said. "Baseball doesn't police itself. They'll be a clamor about fan safety for the next few days and then baseball won't require more netting."

He said the executives who run the national pastime benefit from antitrust exemptions without taking public health and safety seriously. Zlotnick suggested it's time for congressional oversight of fan safety. His injuries left him with $150,000 in medical bills, of which he paid $30,000 out of pocket.

"What we really need to do and what baseball hasn't addressed is these thousands of injured fans who have lifelong injuries and medical bills," he said. "Uninsured people have gone into bankruptcy. There should be a victims' compensation fund."