Short answer. Not while the goods sit with the warehouseman and the negotiable receipt is still outstanding. A creditor cannot attach, garnish, or levy on those goods unless the document is first surrendered to the bailee or a court enjoins its negotiation, and the warehouseman cannot be forced to release them.
What the law says
they cannot thereafter, while in possession of such bailee, be attached by garnishment or otherwise or be levied under an execution unless the document be first surrendered to the bailee or its negotiation enjoined
Civil Code, Article 1519 — Goods Under a Negotiable Document Not Attachable. Read the full provision →
Why the goods are shielded from the sheriff
When goods are deposited with a warehouseman and a negotiable document of title is issued for them, the paper becomes, for commercial purposes, the goods. Whoever holds and can negotiate the receipt controls delivery. If a sheriff could seize the stored goods while the receipt circulates, an innocent person who later took the document for value would be left holding worthless paper, and no bank or trader could safely lend against a warehouse receipt again. The Civil Code therefore blocks attachment, garnishment and levy for as long as the goods remain in possession of such bailee and the document has not been brought under the court's control.
How a creditor can still reach them
The provision is a sequencing rule, not immunity. A creditor has two openings, both written into the text: the document may be first surrendered to the bailee, or its negotiation enjoined. In practice this means the creditor goes after the document itself - asking the court to order the debtor to produce and surrender the receipt, or to restrain any further negotiation of it - before asking the sheriff to touch the stock in the warehouse. Once the receipt is out of circulation or impounded, the danger to a future good-faith holder disappears and the ordinary remedies against the debtor's property become available again.
The warehouseman's position
A warehouseman caught between a demanding sheriff and an outstanding receipt is protected: he shall in no case be compelled to deliver up the actual possession of the goods until the document is surrendered to him or impounded by the court. That is a shield, and refusing on this basis is not defiance of a writ. It is also a warning to depositors and creditors alike that the warehouseman will follow the document, not the identity of the person claiming to own the goods. A bailee who releases stock without taking up the receipt exposes himself to the holder who turns up later.
Limits worth knowing before you rely on this
The protection is tied to conditions that can fail. It applies where a negotiable document of title was issued - a straight or non-negotiable receipt does not carry the same bar. It applies while the goods remain with the bailee; once they are withdrawn, the ordinary rules on levy resume. And it presupposes that the goods were delivered by the owner or by someone whose act would bind the owner, so stolen goods stored under a receipt are a different problem. Creditors should ask early who holds the paper and whether it has been pledged to a bank. This is general legal information, not advice on your collection case.