On January 31st, Customs and Border Protection agents successfully conducted the biggest fentanyl bust in U.S. history. According to the federal agents, a whopping 254 pounds of the dangerous substance was discovered in a truck trailer.

The overwhelming amount of fentanyl wasn’t the only thing hiding in the truck’s false floor. Feds also uncovered 395 pounds of methamphetamine. The meth has an estimated street value of $1.18 million, while the fentanyl is valued at $3.5 million.

Border agents seized the drugs at the Nogales port on the U.S.-Mexico border. Initially, federal agents saw the large truck reportedly transporting cucumbers and referred the vehicle to the secondary inspection area. Here, agents noticed the strange looking floor. A nearby drug-sniffing K-9 alerted officers to the scent of drugs, and that’s when they realized the trailer’s floor was hiding something more sinister.

The truck driver, a 26-year-old Mexican national, was immediately arrested. He is being charged with possession with the intent to distribute.

Authorities are ecstatic to have stopped the dangerous substance from entering into the country. According to the CDC, fentanyl isn’t only dangerous to the people who consume it. Anyone who comes into contact with the substance is in danger because it can easily be accidentally inhaled or absorbed in the skin. Fentanyl is considered such a dangerous drug because tiny salt-sized pieces could be fatal. The CDC reports that fentanyl is the most commonly reported drug associated with modern-day overdoses. In 2016 alone, the drug caused at least 18,000 deaths.