On a Portuguese construction site, identity is normally checked using the details on an ID document, not by keeping a copy of it.
What it means
Checking someone's identity means confirming who they are before they start work. In Portugal, this is done by recording three details from an identity document: the type of document, its number, and its expiry date. These details are enough to confirm identity and to check that the document is still valid.
How it works
For Portuguese workers and workers from the EU or the EEA (the European Economic Area), only these recorded details are used. No copy of the document itself is taken. This follows a general principle in Portuguese data protection rules: collect no more personal data than is actually needed for the purpose at hand.
Why it differs for third-country nationals
Workers from outside the EU or the EEA are treated differently, because they also need residence and work documentation on file. For this group, a copy of the identity document is taken, alongside the recorded details. This extra step is tied to the residence and work-authorisation checks that apply only to this group, not to a general rule about ID copies.
What to watch out for
It is a common mistake to assume every worker's ID document must be copied and kept on file. For Portuguese and EU or EEA workers, this is not the rule: recording the document type, number, and expiry date is enough, and taking a copy anyway goes beyond what is needed.
A copy of the ID document is only taken for third-country nationals. For Portuguese and EU or EEA workers, recording the document type, number, and expiry date is enough.