The phrase "are required because of" is correct and usable in written English.
It can be used to indicate that something is necessary due to a specific reason or circumstance.
Example: "Additional safety measures are required because of the recent increase in accidents at the site."
Alternatives: "are necessary due to" or "are mandated because of".
These lay assistants and substitutes are required because of understaffed or nonstaffed parishes.
Additionally, alternative analgesics are required because of the side effects of currently available analgesics.
Some experts say that serious negotiations are required because of the document's shortage of details.
The only significant revisions proposed in the charter are required because of new norms the Vatican issued last year.
Cooperative movements of multiple adjacent atoms are required because of (1) the small extra volumes created by BD defects and (2) the short-range-only constraint.
They are required because of mounting concerns about pollution in a new lake created by the dam, and because of the proliferation of unforeseen landslides as the riverbank's walls collapse in many places.
Surgeons felt no obvious tumour had been left behind, but that adjuvant therapies such as radiotherapy and chemotherapy were required "because of the risk of microscopic tumour being left behind".
After the second operation surgeons now felt no obvious tumour had been left behind, but that adjuvant therapies such as radiotherapy and chemotherapy were required "because of the risk of microscopic tumour being left behind".
This simple measurement is required because of lack of weighing scales in the community, and sometimes in the health facilities.
However, in many cases, specific battery chemistry is likely to be required because of the power requirements.
Transfusion requirement: A hemoglobin level of ≥10 g/dL was required because of its widespread use in clinical medicine [ 22].
