This isn't the first cooperative arrangement for ECHA. They signed a "statement of intent" with the USEPA last December in which the two agencies agreed to "share data, cooperate with each other on chemical reviews, and even exchange staff."
According to ECHA:
One of the anticipated areas of collaboration will be exchange of information. For example, the Memorandum of Understanding will promote the exchange of non-confidential information on hazards, uses and identity of chemical substances between ECHA and NICNAS. The agencies will also be sharing information on ways to more efficiently address chemicals of concern.
The full MOU can be downloaded as a PDF file here.