Many fast food favorites have what health experts consider dangerously high levels of phthalates, toxic plastic chemicals that leech into food products.

From Taco Bell, McDonald's and Chick-fil-A to even healthier options like Sweetgreen, phthalates have infiltrated a sector of the food industry that millions of Americans turn to for accessible and inexpensive food.

Fast food is known to be high in calories, fats, and sugar, but many consumers are unaware that their drive-through favorites are laced with the additives used to make plastic items more flexible and long-lasting that leach from their packaging into the food.

The lengthy journey from raw ingredient to store shelf creates multiple opportunities for phthalates to contaminate food. These chemicals migrate from plastic packaging, manufacturing equipment like PVC conveyor belts, plastic tubing and workers' gloves during handling. 

Exposure over time to phthalates is believed to contribute to a wide range of illnesses. As disruptors of the hormone regulation system in the body, the plasticizers have links to breast cancer, decreased fertility, low birth weight, obesity and diabetes.

Phthalates also have links to impacting the immune and cardiovascular systems, contributing to heart attacks, strokes and high blood pressure, as well as system-wide inflammation that can exacerbate existing health problems. 

The latest data on phthalates in foods comes from PlasticList, a database run by former tech leaders, epidemiologists, and privately funded labs with environmental and biomedical experts.

Researchers behind PlasticList tested more than 615 products purchased from stores and fast food restaurants around the San Francisco Bay area for 18 different types of phthalates. They measured phthalate levels in nanograms per serving of food.  

There were several standouts in the database. The Taco Bell Cantina Chicken Burrito, for instance, was reported to contain more than 14,000 nanograms of DEHP per serving, while a Burger King Whopper with cheese contained roughly 9,800 ng per serving of DEHP.

DEHP is associated with a range of serious, long-term health effects, primarily due to its action as an endocrine disruptor. It interferes with the body's hormone systems, leading to developmental, reproductive, metabolic and other systemic problems. 

Many items on PlasticList contained thousands of nanograms of other phthalates in addition to DEHP, such as DEHT and DEHA.

The chemical analysis underpinning PlasticList was performed by a leading, anonymous lab to ensure impartiality. 

The method used was isotope dilution mass spectrometry, the gold standard because it not only measures the amount of phthalates left at the end of production, but it also actively corrects for the flaws and losses in the measurement process, which most other methods cannot do. 

This method involved adding a known quantity of specially tagged versions of the target phthalates to each sample at the start. These tags allow the lab to precisely track and correct for any loss of the chemicals during processing, guaranteeing highly accurate measurements of the phthalates and bisphenols originally present in the food. 

There were several standouts in the database. 

The Burger King Whopper with Cheese is the most concerning item overall. It is the top offender for DEHT, containing a staggering 5.8 million nanograms per serving and also ranks highly for DEHA and DEHP. 

For DEHA, the Burger King Whopper again led at 12,324 nanograms, nearly double the next highest item.

The Burger King Vanilla Shake also contained alarming concentrations of the chemicals, including 15,300 nanograms of DEHP, 45,000 nanograms of DEHT and 9,000 nanograms of DEHA.

The Wendy’s Dave Single with Cheese contained 3,680,000 nanograms of DEHT, and Chick-fil-A’s Deluxe Sandwich had 2,717,000 nanograms. 

The Wendy's Dave Single contained 9,280 nanograms of DEHP, placing it firmly in the high-tier. 

The Chick-Fil-A Deluxe Sandwich contained 8,151 nanograms of DEHP, also a high level for this chemical and 3,705 nanograms of DEHA. 

For the better-studied and more toxic phthalate DEHP, the Shake Shack Cheeseburger had the highest level at 24,045 nanograms, followed by the Taco Bell Cantina Chicken Burrito at more than 14,200 nanograms and the Burger King Whopper with Cheese at 9,796 nanograms

The list even included healthy options, such as Sweetgreen's Chicken Pesto Parm Salad, which consisted of 30,415 nanograms of DEHP, 1,363,145 nanograms of DEHT and 223,175 nanograms of DEHA, as well as baby food and formula.

Gerber Baby Food Banana and Glass was listed as containing more than 9,000 nanograms of DEHT. Cans of Enfamil Neuro Pro Infant Formula were reported to have more than 2,200 nanograms of DEHP.

There is no universally 'safe' amount of exposure to phthalates, which are present in the air, the ground and common household ingredients. 

A general consensus among researchers, determined through analyses of clinical trials, determines the No-Observed-Adverse-Effect Level (NOAEL), which indicates the highest dose at which no harm is observed, though there is no uniform safe level determined by government agencies. 

For DEHP, the No-Observed-Adverse-Effect Level (NOAEL), the highest dose at which no harm was observed, as determined by toxicologists, is 4.8 mg/kg/day. For the average 150lb person, that is approximately 326 mg per day.  

The Tolerable Daily Intake (TDI), the level deemed safe for lifelong human exposure, is set 100 times lower, at 48 μg/kg/day. 

For DEHT, the European Food Safety Authority has derived a TDI of 1.2 mg/kg bodyweight per day. 

The established NOAEL for DEHA is 19mg/kg bodyweight per day, based on liver and kidney effects in long-term animal studies. 

The Tolerable Daily Intake (TDI) set by EFSA is 0.3 mg/kg bodyweight/day. This is six times higher than the TDI for DEHP but four times lower than the TDI for DEHT. For that 150lb person, that would be 20.4 mg per day. 

Fast food Ingredients are usually mixed, cooked and transported through plastic-lined industrial tubing, PVC conveyor belts and plastic vats.

The final product is sealed in plastic wrappers, clamshells, or lined cans and cartons. 

Here, it sits for an extended period of time, allowing for continuous, slow migration of additives from the packaging material into the food, especially if the food is oily, acidic, or microwaved in its packaging.

Chemicals such as DEHP are lipophilic, meaning they have a powerful natural attraction to oils and fats. When hot, greasy food comes in contact with plastic packaging or equipment, these chemicals are rapidly pulled out of the plastic and dissolved directly into the food's fat, which continuously draws more of the plasticizer chemicals and locks them in. 

Children's developing endocrine and neurological systems are uniquely vulnerable to phthalates' disruptive effects, which are linked to developmental, cognitive and behavioral issues.

For pregnant women, exposure during critical windows of fetal development can have lifelong consequences for the child, impacting reproductive development and increasing risks for learning and attention problems. 

Studies have shown that meals high in meat and fat correlate with higher urinary levels of phthalate metabolites. 

Of the phthalates studied, DEHP’s harms are backed by the most evidence. Human epidemiological studies have consistently linked exposure to adverse reproductive outcomes, including reduced semen quality, altered genital development in male infants and earlier menopause in women.

It is also strongly associated with metabolic disturbances, contributing to insulin resistance and obesity, particularly in children.

DEHT is believed to be a safer alternative to DEHP, but studies into the potential harms of exposure have not been closely scrutinized.

Unlike DEHP, DEHT has shown no evidence of reproductive toxicity in rat studies and does not appear to have the same adverse effects on reproductive organs.

Still, emerging evidence indicates that it may act as an endocrine disruptor, noting links with hormone imbalances in humans, such as elevated estrogen during pregnancy.

DEHA, used in food packaging, is metabolized differently than DEHP and is generally less potent as an endocrine disruptor.

However, animal studies indicate that high-dose exposure can lead liver and kidney damage, including cancers, testicular atrophy, prolonged pregnancy, increased infant death and low birth weight.

The International Agency for Research on Cancer (IARC) has classified DEHA as possibly carcinogenic to humans based on sufficient evidence of liver cancer in animals but inadequate evidence in humans.