This piece originally aired Dec. 6, 2017.

There's a warning about the dangers of using counterfeit makeup and other knockoff products like toothpaste and cologne. U.S. Customs and Border Protection seized a record number of counterfeit goods last year, worth nearly $1.4 billion. One of their top priorities is spotting fake toiletries that can be hazardous to your health.

Customs agents seized more than 2,000 shipments of counterfeit beauty products last year alone. They said fake personal care items are now even more common than knockoff handbags.

CBS News correspondent Jamie Yuccas and her team visited a warehouse near the Long Beach Seaport where officers take a closer look at suspicious packages. Most of the boxes waiting for further inspection are from China and Hong Kong. The customs officers are the first line of defense for catching illegal shipments. While the products may be fake, they can have very real health consequences for consumers.

Beauty blogger Tanya Arguelles CBS News

Beauty blogger Tanya Arguelles found out first hand when she purchased a popular eyeshadow from a downtown Los Angeles street market last year. U.S. customs officers say most of the discounted goods sold there likely snuck in under the radar at sea ports like Long Beach.

"I just wanted to know, can this possibly be as good as the $50 that I just spent?" Arguelles said.

She tested both eye shadows and when she woke up the next morning, her eye was burning, uncomfortable and itchy.

"Within the first 45 minutes, I realized that it was an eye infection. I couldn't get my contacts on," Arguelles said. "I looked back at the footage and it was on the fake side. Hundred percent."

Arguelles isn't alone. Other people who have used counterfeit makeup have reported allergic reactions, skin rashes, swollen lips and chemical burns.

We wanted to find out how easy it is to find the products, so we went shopping undercover at the same downtown alley. Most of the fake makeup sold here is half the price of the original. Some vendors admitted the products were knockoffs but assured us they were just as good.

"It works the same thing as the original," one vendor said.

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Back at Arguelles' studio, we compared our purchases with the same makeup from traditional retail stores. The packaging is nearly identical.

Some fake makeup has reportedly been found to contain dangerous chemicals such as arsenic, mercury and aluminum. We sent the fake and real versions of a Mac lipstick and a Jaclyn Hill eye shadow palette to a lab where they were tested for 12 different metals. Most concerning: some of the eye shadows in the fake palette had nearly four times the amount of lead as those in the real version. In one, the amount exceeded the FDA recommended maximum of 10 parts per million. The fake lipstick had nearly 15 times the amount of lead as the real thing.

"Often the unsafe consumer goods are made in factories… have unsanitary conditions," said Brenda Smith, executive assistant commissioner for Office of Trade at U.S. Customs and Border Protection. "So the quality is not to what you need it to be."

Customs and Border Protection said the counterfeit products are costing the cosmetic industry about $75 million a year. They said reducing the amount of fake products smuggled into the country could be as simple as educating customers.

"The furthest they think is, I'm just buying a fake palette. They don't think that there could be ingredients in here that could put my health at risk," Arguelles said.

Fake products like makeup aren't just sold in downtown Los Angeles. Costumers need to pay close attention to hot ticket items they find online if the prices seem too good to be true. Beauty bloggers say the best way to know you are getting the real thing is to log onto the cosmetic company's official website to find out where their items are sold.