A desperate search for possible stowaways continued into Wednesday night on a container ship at the Port Newark-Elizabeth Marine Terminal.

Authorities from the Department of Homeland Security spent all day yesterday inspecting the Ville D’Aquarius after a faint knocking was heard coming from inside one of the containers on board, after the ship docked. The ship arrived in Newark from Egypt at around 8:30 a.m. yesterday.

“They’ve opened several (containers) but haven’t found anything,” a U.S. Coast Guard spokeswoman told Metro.

Inspectors used X-rays to examine the contents of the nearly 2,000 containers aboard. Officials told the Newark Star-Ledger that it takes approximately eight minutes to search each container.

The standard size of these containers ranges from 20 to 40 feet long. They are about eight feet tall and eight feet across.

The vessel was originally suspected of carrying stowaways during a routine inspection; authorities knocked on a container and heard knocking back. No sounds were reported since.

According to Reuters, the specific container suspected of harboring several stowaways was loaded onto the ship on June 7 in India. Officials were concerned how anyone could survive a 20-day trip trapped in a dark, cramped container. At least seven ambulances waited outside the port’s entrance yesterday.

The ship’s manifest said the container was carrying machine parts.

Yesterday was not the first time the port of Newark received possible stowaways.

Last year an Egyptian man found living in a New Jersey warehouse claimed he had eluded border patrol by stowing away in a ship that arrived in Newark, reported the Post.

Asem Haroon was also suspected of being a terrorist, as the Port is located near several oil refineries, a known target of al Qaeda.

How could anyone survive?

The odds of surviving in cargo containers for a period that long is “somewhat unlikely,” Dr. Mary O’Brien, a New York City physician, told Metro.

“Depending on the temperature they could die of hypothermia or heat exhaustion,” explained O’Brien. “The second part is how much water there is … if they’re sweating they could be losing a lot of water quickly.”

In addition to the heat, freezing to death could also be a concern, as some containers can maintain temperatures of -76 degrees Fahrenheit.

O’Brien added that food was not necessarily crucial to survival, but if the container was sealed too tightly it would be possible for the stowaways to use up all the oxygen over the journey.