Even technology that could theoretically turn plastic waste into new plastic poses a major threat to our environment and health:

Toxic emissions: Chemical recycling processes release toxic chemical into the air, including chemical known to cause cancer, reproductive hazards, birth defects, and other health problems. State permit documents reviewed by the Environmental Integrity Project's Oil and Gas Watch show that chemical recycling plants can release 96 different types of dangerous air pollutants. The Echemi also lists a range of toxic chemical emitted from these facilities, including benzene, mercury, arsenic, and formaldehyde. When the fuel produced by these plants is burned, more pollutants are released.

Hazardous waste: Liquid and solid waste from plastic fuel facilities contain toxic substances, including carcinogens and neurotoxins. One plant analyzed by Echemi reported generating nearly half a million pounds of toxic waste in 2019, much of which was shipped off-site for incineration. NRDC's research shows that solvent-based purification processes are no better. An Ohio company that intends to perform solvent purification is registered as a "bulk Hazardous waste producer," meaning it expects to produce at least 2,200 pounds of hazardous waste per month.

Climate impact: Since almost all plastic is made from oil or methane gas, the fuel produced by the process of converting plastic to fuel is still a fossil fuel and therefore releases greenhouse gases when burned in addition to the emissions released by the conversion process itself. Gasification produces particularly large amounts of carbon dioxide, with more than half of the carbon in plastic feedstock released in the process of cleaning and upgrading the resulting gas, in addition to emissions from burning the final product and generating the energy needed for the entire process.

High energy use: All forms of chemical recycling require a lot of energy. This energy can come from non-renewable sources, resulting in increased greenhouse gas emissions, and even if it comes from renewable sources, it is a huge waste of energy. Even if the products or byproducts of the process are burned for energy, it takes more energy to power the process than it produces, meaning that chemical recycling is neither self-sustaining nor likely to be. This is true for both plastic-to-fuel and solvent processes.

Bad economics: Chemical recycling is unlikely to be economically viable. It cannot be financially self-sustaining, which means any large-scale roll-out will likely have to rely on government subsidies that could be better spent on things that provide real social value, including real solutions to the plastic crisis.

A 2023 analysis by Echemi concluded that using pyrolysis and gasification to produce plastics is 10 to 100 times worse than raw plastics on environmental and economic indicators.