--- type: restriction id: usps-biological-products-exceeding-4-liters-or-4-kg-containing-category-a asset: shipping-restrictions-by-class title: "Biological products exceeding 4 liters or 4 kg containing Category A — Postal shipping restrictions by item category" sources: - https://pe.usps.com/text/pub52/pub52c3_025.htm source_quote: "Biological Products and Specimens: Biological products, cultures, stocks, or other biological specimens known or suspected to contain a Category A infectious substance. Mailpieces exceeding 4 liters (1 gallon) for liquids or 4 kg. (8.8 pounds) for solids are nonmailable." generated: true harvested: 2026-08-04 stale_after: 2027-08-04 item_category: "Biological products exceeding 4 liters or 4 kg containing Category A" carrier: "USPS" restriction_type: "prohibited" scope: "all mail" conditions: "Biological products, cultures, or specimens known or suspected to contain Category A infectious substance, or exceeding 4 liters/4 kg limits, are nonmailable" verified: true unverified_fields: carrier, scope --- **Item category:** Biological products exceeding 4 liters or 4 kg containing Category A **Carrier:** USPS **Restriction type:** prohibited **Scope:** all mail **Conditions:** Biological products, cultures, or specimens known or suspected to contain Category A infectious substance, or exceeding 4 liters/4 kg limits, are nonmailable > Biological Products and Specimens: Biological products, cultures, stocks, or other biological specimens known or suspected to contain a Category A infectious substance. Mailpieces exceeding 4 liters (1 gallon) for liquids or 4 kg. (8.8 pounds) for solids are nonmailable. Source: