SAN DIEGO (CBS) — The nation’s busiest border crossing slowly reopened Thursday after a wooden platform collapse left 11 people hospitalized — including a pregnant woman — with one construction worker left in serious condition.

KNX 1070’s Tom Reopelle reports the collapse also made a mess of border traffic coming into and going out of Southern California.

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The scaffolding above a construction zone at San Ysidro Port of Entry left nearly half of the 24-lane crossing closed after debris — including support beams and concrete pieces — fell on dozens of vehicles, officials said.

All traffic out of Mexico was halted in order to let paramedics attend to three people who were temporarily trapped when a 50-by-50-foot wooden platform on East San Ysidro Boulevard gave way about 10:45 a.m. on Wednesday, according to the San Diego Fire-Rescue Department.

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“They did primary searches and secondary searches to make sure that all the people that were in the vehicles that had debris on them had gotten out of the vehicle,” said SDFRD spokesman Maurice Luque.

Officials are still unsure when the crossing’s remaining lanes will reopen, but any overflow traffic will be rerouted five miles east to Otay Mesa.

Federal engineers were called in to assess remaining hazards at the site and develop a cleanup plan.

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The closure of the border port, which is in the midst of a major renovation and upgrade project, could last as long as 12 hours, according to Mayor Jerry Sanders’ office.

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