As a biological product, dried moss must comply with Phytosanitary Regulations. Ensure the supplier can provide a Phytosanitary Certificate issued by their national plant protection organization to prove the product is free from pests and diseases. For interior design projects, look for Fire Retardant Certification (e.g., ASTM E84 or EN 13501-1) to meet building safety codes. Additionally, confirm that the dyes and preservatives used are REACH or RoHS compliant, ensuring they are free from heavy metals and harmful chemicals.