A Laboratory Project Agreement (PLA), also known as the Community Workforce Agreement, is a pre-employment collective agreement with one or more labour organizations that sets the terms and conditions for a given construction project.  Before workers are hired for the project, construction unions have the right to negotiate, determine wage rates and benefits for all workers working on the project concerned, and approve the provisions of the agreement.   The terms of the agreement apply to all contractors and subcontractors who offer success for the project and replace all existing collective agreements.  PLAs are used for both public and private projects and their specific provisions can be adapted by the signatory parties to the needs of a given project.  The agreement may contain provisions to prevent strikes, lockouts or other work stoppages during the duration of the project.  As a general rule, TTPs require that employees recruited for the project be returned to union rental premises, that self-employed workers in trade unions pay trade union rights for the duration of the project, and that the contractor comply with union rules on pensions, working conditions and dispute resolution.  With the February 2009 stimulus package, which provided approximately $140 billion for federal, regional and local construction projects, fighting for government-mandated LTCs for public construction projects was widespread at the state and local level from 2009 to 2011. Government officials and legislators have argued over the use of PLA mandates for projects in states such as Iowa, Oregon, Ohio, California and others.   Some municipalities voted to ban the use of mandatory LPOs for taxpayer-funded construction projects, including election initiatives in Chula Vista, Oceanside and San Diego County, California, in 2010, which led to a ban on officials hiring or banning PPPs for government projects.
 In 2011, contractors filed with the Government Accountability Office against government-mandated PLAs for construction projects in New Hampshire, New Jersey, Pennsylvania and Washington, D.C. These protests led to the departure of federal warrants from tenders.  In 1997, Clinton proposed an executive order that requires federal authorities to consider the use of LTOs for Federally funded projects.  Republicans strongly opposed it and believed it would limit federal projects to union entrepreneurs alone.