Four people were injured Monday during the morning commute on the Long Island Expressway when four vehicles collided after ladders fell off a box truck, the Suffolk sheriff's office said.

A huge traffic jam ensued when three lanes of the eastbound LIE were closed for up to 90 minutes east of Exit 49 following the 7:59 a.m. accident in Melville, the sheriff's office said.

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Four vehicles - two sedans and two utility trucks - crashed while trying to avoid several ladders that fell from the exterior of a white box truck, said Chief of Staff Michael Sharkey of the sheriff's office. Both sedan drivers and a passenger in one of the cars received minor injuries. A driver of one of the utility trucks also had minor injuries.

The box truck driver, apparently unaware of the accident, was stopped by a sheriff's deputy. The unidentified driver was issued three summonses, including one for having an unsecured load, Sharkey said.

Traffic returned to normal when the last of the closed lanes was reopened at 9:27 a.m.