Breakdown of Hay que usar el casco por seguridad.
que
that (relative pronoun, conjunction)
por
for / by / through / in (during a part of the day)
hay que
one must, it is necessary to (+ infinitive)
la seguridad
the safety / security (guards, staff)
Questions & Answers about Hay que usar el casco por seguridad.
Why is it hay que and not tener que here?
Does hay que change depending on who needs to wear the helmet?
No, hay que never changes form in the present tense because it doesn't refer to a specific person. It is always just hay que followed directly by an unconjugated verb (an infinitive), like usar in this sentence.
Why do we use por instead of para in por seguridad?
We use por here because it explains the reason or motive behind the action, meaning "for the sake of" or "because of". So, por seguridad translates to "for the sake of safety" or "for safety reasons". If you used para, it would sound like you are trying to achieve the concept of safety, rather than acting because of it.
Why does it say el casco (the helmet) instead of just un casco (a helmet)?
When talking about things in a general sense or referring to a standard piece of daily equipment, Spanish often uses the definite article (el, la, los, las). While in English you might say "wear a helmet," Spanish prefers el casco to refer to the general category of safety helmets.