Three containers fell from an MSC boxship on to a Greek tanker during a smash in the Houston Ship Channel.
The MSC-managed 3,007-teu MSC Nederland (built 1992) was in collision on Saturday with the 105,000-dwt aframax Elka Apollon (built 2005), operated by European Product Carriers.
Both vessels were damaged in the accident where the Bayport Ship Channel connects to the Houston waterway.
A small amount of hydraulic fluid leaked from tractor equipment in one of the containers.
No injuries were reported.
The US Coast Guard is investigating the cause of the incident.
By Gary Dixon in London