[CNN] A mountain of food, water and other vital supplies has arrived in Puerto Rico's main Port of San Juan.But a shortage of truckers and the island's devastated infrastructure are making it tough to move aid to where it's needed most, officials say.
At least 10,000 containers of supplies -- including food, water and medicine -- were sitting Thursday at the San Juan port, said Jose Ayala, the Crowley shipping company's vice president in Puerto Rico.
Part of the reason for the distribution backlog is that only 20% of truck drivers have reported back to work since Hurricane Maria swept through, according to a representative for Puerto Rican Gov. Ricardo Rosselló.
On top of that, a diesel fuel shortage and a tangle of blocked roads mean the distribution of supplies is extremely challenging. Even contacting drivers is a problem because cell towers are still down.
"When we say we that we don't have truck drivers, we mean that we have not been able to contact them," Rosselló said.
On Thursday the White House authorized a 10-day waiver of the Jones Act, a federal law that limits shipping to US ports by foreign vessels. Puerto Rico's governor and other US officials had argued that a waiver would expedite supplies to the island.