All substances with phase-in status that are produced or imported into the EU in quantities above 100 tonnes per year must be registered on 31 May 2013 the latest.
To benefit from the staggered registration deadlines, phase-in substances that are manufactured or imported above the one-tonne threshold need either to have been pre-registered by the original pre-registration deadline in 2008 or "late" pre-registered within six months of the first manufacture or import of the substance. However, the possibility to "late" pre-register substances to be registered by 31 May 2013 ends one year before the deadline, i.e. on 31 May 2012.
After that date, companies need to submit an inquiry to ECHA and register the substance before manufacturing/importing can take place.
Substances that need to be registered by the 2018 REACH registration deadline, i.e. substances that are for the first time manufactured or imported in quantities between 1-100 tonnes per year (and not classified as CMRs) can still be "late" pre-register within 6 months of the first manufacturing or importing.