Chicago Cubs outfielder Albert Almora Jr. hit a 106 mph line drive in May that screamed into foul territory down the left-field line at Houston’s Minute Maid Park. The ball hit a 2-year-old girl, who was rushed out of the stadium. The game stopped as an emotional Almora dropped to a knee. Less than two weeks later, as the Washington Nationals played the White Sox in Chicago, a woman sitting just past the third-base dugout was struck in the face. Less than two weeks after that, a Dodger Stadium spectator sitting just past the netting on the first-base line was hit in the head by a hard line drive off the bat of right fielder Cody Bellinger.

Bloomberg News estimated in 2014 that 1,750 fans per year are hurt by batted balls at MLB games. Amid debates over how much protection teams should offer spectators, we wanted to find out which areas of stadiums might be the most dangerous, which could help us figure out what could be done to prevent more fan injuries.

Because there’s no central database of all of MLB’s foul balls, we had to compile a data set ourselves. To do that, we searched the batted-ball data for this season on Baseball Savant to find the 10 stadiums that produced the most foul balls up to June 5 and then analyzed the pitch-level data from the most foul-heavy game day at each of those stadiums (including one doubleheader). Because we had to individually research each foul ball, we couldn’t look at a whole season’s worth of fouls. By limiting the data set to the most foul-heavy days of play in those 10 stadiums, we aimed to keep the data set to a manageable size while also capturing the largest number of fouls we could from a variety of parks, since stadiums vary dramatically in architecture, altitude and seating arrangements.

Dozens of fouls per game in the most foul-heavy parks The most foul-heavy day at each of the 10 stadiums that produced the most fouls this season, as of June 5 Most foul-heavy day Stadium Average No. of Fouls per game Date Matchup No. of Fouls Camden Yards* 57 4/20/19 Baltimore Orioles vs. Minnesota Twins 113 PNC Park 57 6/1/19 Pittsburgh Pirates vs. Milwaukee Brewers 111 Oakland Coliseum 53 6/2/19 Oakland A’s vs. Houston Astros 109 T-Mobile Park 53 5/18/19 Seattle Mariners vs. Minnesota Twins 100 Globe Life Park 55 5/3/19 Texas Rangers vs. Toronto Blue Jays 87 Dodger Stadium 51 3/29/19 Los Angeles Dodgers vs. Arizona Diamondsbacks 86 Miller Park 55 5/4/19 Milwaukee Brewers vs. New York Mets 85 Citizens Bank Park 53 4/27/19 Philadelphia Phillies vs. Miami Marlins 75 SunTrust Park 53 4/14/19 Atlanta Braves vs. New York Mets 73 Yankee Stadium 51 3/31/19 New York Yankees vs. Baltimore Orioles 67 * Includes both games of the doubleheader Source: Baseball Savant

We watched clips of 906 foul balls hit during those games (excluding foul tips, which were never in danger of reaching the stands, and fouls that resulted in outs, because Baseball Savant groups those with other types of caught-ball outs, so we couldn’t get data on foul outs specifically), and we recorded whether the fouls were grounders, fly balls, line drives or pop-ups. Then we split the parks into “zones” to categorize the general area where each of those balls landed.

Zones 1, 2 and 3 include seats that are largely protected by netting — the area behind home plate and both dugouts — along with the corresponding areas of foul territory on the field. Zones 4 and 5 are mostly non-netted seating areas and the foul territory outside the baselines, from the dugout to the foul pole. Zones 6 and 7 cover the areas past the foul poles; the fly balls that land here typically have too much arc to be dangerous, and line drives rarely make it that far.

Less than half of the foul balls we charted were followed by a camera to where they landed. But by gauging angles, we estimated where all of the fouls — both those that were followed by a camera and those that weren’t — likely landed. We tested our predictions against the footage of the balls that were followed to check our accuracy.

Nearly equal shares of foul balls ended up in zones with netting vs. zones that largely lack netting: 454 balls landed in zones 1, 2 and 3, while 452 balls fell in zones 4 through 7.

The scariest foul balls are those with high exit velocities, particularly the line drives, which give spectators only seconds — or fractions of a second — to react. Statcast was able to measure exit velocities for 580 of the 906 foul balls in our data set, and most of the hardest-hit of those 580 landed in areas that are primarily unprotected. Of the fly balls with recorded exit velocities of 90 mph or higher, 71.8 percent landed in zones 4 and 5. And all of the line drives that left the bat at 90 mph or more landed in those same zones. That’s the type of hit that injured the toddler at this year’s Cubs-Astros game or that blinded a man in one eye at Wrigley Field in 2017.

Major league stadiums have slowly been installing more netting around the field. Players have been pushing the issue, including Dodgers pitcher Rich Hill, who called the MLB Players Association to voice his support for more protective netting. In 2015, MLB encouraged teams to extend netting to the “near ends of both dugouts.” By 2018, all 30 stadiums had exceeded that recommendation, installing netting from one end of the dugout to the other. After the incident at Guaranteed Rate Field, the White Sox announced that they would implement netting from foul pole to foul pole, and crews worked during the All-Star break to install the new nets. The Washington Nationals also used the break to add netting.

But more netting won’t protect every fan. Linda Goldbloom was sitting high above home plate in Dodger Stadium — in zone 1, where netting is provided — last year when she was struck and killed by a high fly ball that had an exit velocity of just 73 mph. And a woman at Tropicana Field was hospitalized in 2016 after she was hit by a fly ball that found its way through a hole in the netting just to the left of the first-base dugout.

The efforts that other leagues make to ensure the safety of their spectators could serve as a blueprint for MLB. Take the Japanese Nippon Professional Baseball Organization, where the stadiums have netting from foul pole to foul pole. Whenever a ball is hit into the stands, fans are warned with loud whistles blown by staff stationed in their seating section, and animated warning videos are played before every game. As a result, unprotected seats are something of a luxury in Japan. The Tokyo Dome offers “exciting seats” near the foul lines, which come equipped with helmets and gloves.

Even with extensive netting, no one will ever be completely safe at a baseball game. But there are ways for MLB to protect its fans from foul balls — particularly in the most dangerous areas of the park.

“It’s something that you just hold your breath for a second,” Hill told The Los Angeles Times. “You just hope it hits a seat, not a person.”

Neil Paine contributed research.

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CORRECTION (July 15, 2019, 5 p.m.): A previous version of this story referred to the data as having been collected from the 10 most foul-ball-heavy games this season. It was actually collected from the 10 most foul-ball-heavy game days — one day included a doubleheader.