A law requiring that most materials in federally funded affordable housing are made in America is fully kicking in. But it is wreaking havoc on affordable developments. Developers are reporting delays, higher costs and hundreds of hours spent figuring out how to comply with the Build America, Buy America Act as prices soar for renters and homebuyers. Developers and housing agencies can ask for exceptions, but the Department of Housing and Urban Development has hardly been approving those requests. The process is going more smoothly for other agencies. The law's supporters say it will boost American manufacturing jobs.