LAGOS, Nigeria: A Nigerian engineers association said the 21-story building that collapsed in Lagos early this month was originally designed for only six floors before more were added to the structure. The high-rise building was still under construction in the upscale Ikoyi district of the city when it crumbled on November 1, trapping dozens of site workers and others inside. At least 45 people — including the owner of the building — were killed while 15 were pulled from the debris alive, according to the latest tally by the state government. The engineering institution statement came as news emerged that another two-story building under construction had collapsed on Wednesday (Thursday in Manila) in Lagos, where emergency services said four people were killed and five workers were rescued. Building collapses are common in Africa’s most populous country where millions live in dilapidated properties and construction standards are routinely ignored.