English to Italian Law/Patents Law: Contract(s)

Test per "giusta causa", per "fondato motivo" ? Non trovo niente in rete di simile...un'idea? Grazie!

Il contesto (uso/vendita/distribuzione di sostanze stupefacenti / alcolici sul posto di lavoro):
Buyer's employee, agent or contractor may be considered for return to Seller's facilities only if the Buyer certifies as a result of a ***for cause test***, conducted immediately after removal, that said employee, agent or contractor was in compliance with the provisions of this Paragraph. Buyer will not use an employee, agent or contractor to perform activities hereunder who either refuses to take, or tests positive in, any alcohol or drug test.