When REACH is fully in force, it will require all companies manufacturing or importing chemical substances into the European Union in quantities of one tonne or more per year to register these substances with a new European Chemicals Agency (ECHA) in Helsinki, Finland. Since REACH applies to some substances that are contained in objects (articles in REACH terminology), any company importing goods into Europe could be affected.^[4]

The European Chemicals Agency has set three major deadlines for registration of chemicals. In general these are determined by tonnage manufactured or imported, with 1000 tonnes/a. being required to be registered by 1 December 2010, 100 tonnes/a. by 1 June 2013 and 1 tonne/a. by 1 June 2018.^[5] In addition, chemicals of higher concern or toxicity also have to meet the 2010 deadline.

About 143,000 chemical substances marketed in the European Union were pre-registered by the 1 December 2008 deadline. Although pre-registering was not mandatory, it allows potential registrants much more time before they have to fully register. Supply of substances to the European market which have not been pre-registered or registered is illegal (known in REACH as "no data, no market").

REACH also addresses the continued use of chemical substances of very high concern (SVHC) because of their potential negative impacts on human health or the environment. From 1 June 2011, the European Chemicals Agency must be notified of the presence of SVHCs in articles if the total quantity used is more than one tonne per year and the SVHC is present at more than 0.1% of the mass of the object. Some uses of SVHCs may be subject to prior authorisation from the European Chemicals Agency, and applicants for authorisation will have to include plans to replace the use of the SVHC with a safer alternative (or, if no safer alternative exists, the applicant must work to find one) - known as substitution. As of 17 December 2014^[update], there are 161 SVHCs on the candidate list for authorization.^[6]

REACH applies to all chemicals imported or produced in the EU. The European Chemicals Agency will manage the technical, scientific and administrative aspects of the REACH system.

To somewhat simplify the registration of the 143,000 substances and to limit vertebrate animal testing as far as possible, Substance Information Exchange Forums (SIEFs) are formed amongst legal entities (such as manufacturers, importers, and data holders) who are dealing with the same substance.^[7] This allows them to join forces and finances to create 1 registration dossier. However, this creates a series of new problems as a SIEF is the cooperation between sometimes a thousand legal entities, which did not know each other at all before but suddenly must:

• find each other and start communicating openly and honestly
• start sharing data
• start sharing costs in a fair and transparent way
• democratically and in full consensus take the most complex decisions

in order to complete a several thousand end points dossier in a limited time.

The European Commission supports businesses affected by REACH by handing out – free of charge – a software application (IUCLID), which simplifies capturing, managing and submitting of data on chemical properties and effects. Such submission is a mandatory part of the registration process. Under certain circumstances the performance of a Chemical Safety Assessment (CSA) is mandatory and a Chemical Safety Report (CSR) assuring the safe use of the substance has to be submitted with the dossier. Dossier submission is done using the web-based software REACH-IT.( Quotation from WIKIPIDIA )