Tight security measures will be in place for the Preakness Stakes this year. (Jonathan Newton/WASHINGTON POST)

Fans attending the May 18 Preakness Stakes won’t be allowed to bring backpacks into the Pimlico Race Course infield and face further restrictions that have been enacted at Pimlico in response to the bombings at the Boston Marathon two weeks ago.

For the first time, all fans entering the gates will undergo an electronic wand search. Items carried into the grandstands or infield will be subject to further searches. And the list of things not permitted has been expanded.

Neither backpacks nor duffle bags will be allowed in the infield. All coolers are banned unless they are clear, see-through containers (akin to plastic storage bins), no larger than 25 inches long, 15 inches wide and 17 inches high.

Also prohibited: Cameras with detachable lenses or a lens longer than six inches, laser lights and pointers and beverages of all kinds — water included. The new restrictions will also be in effect for Black-Eyed Susan Day on May 17.

Maryland Jockey Club President Tom Chuckas said the heightened measures were adopted after race officials consulted with law enforcement and public safety officials at the state and federal levels.

When the Maryland Jockey Club last tightened its infield rules in 2009, barring spectators from bringing in beer and alcohol over concerns that the debauched atmosphere posed a safety hazard, attendance plunged roughly 30 percent the following year before bouncing back after an ad campaign trumpeting $20 bottomless mugs of beer.

Chuckas hopes that fans will respond more soberly to these restrictions.

“With any change, there is usually some backlash,” Chuckas said following Tuesday’s announcement of the new security measures. “I respectfully request people understand these changes are made for reasons of safety. You can take a look at Boston to see what transpired there. We’re trying to do these changes with minimal inconvenience. And we think these changes will go a long way toward ensuring their safety and security.”

For those planning to spend all afternoon at the track, a certain amount of gear is necessary, such as sunscreen, a hat and snacks. Pimlico will allow fans to carry in beach bags, Chuckas said, because they’re relatively easy to examine, lacking the multiple compartments of backpacks.

A full list of what is and isn’t permitted is available at preakness.com.

The Preakness Stakes, held at Pimlico Race Course just outside Baltimore, typically draws the biggest crowd of any sporting event in the Washington area. More than 100,000 have attending the second leg of thoroughbred racing’s Triple Crown 10 of the last 12 years. A record crowd of 121,309 attended last May to watch Kentucky Derby winner I’ll Have Another thunder to victory.

While race-day security has been beefed up, Chuckas urged fans to report any unusual or suspicious behavior to authorities and advised fans to arrive early to avoid potential backlogs at the gates.

Fans attending Saturday’s Kentucky Derby at Churchill Downs in Louisville will be subject to similar restrictions in the wake of the Boston bombings.