The Hudson River, like many large rivers that flow through cities, faces a lot of pollution. Sources of pollution include large chemical factories, farms, and household waste. A major issue is the release of polychlorinated biphenyls (PCBs) from General Electric factories. Other types of pollution include mercury and sewage that is not properly treated. The New York State Department of Environmental Conservation (NYSDEC) has identified sections of the Hudson River with poor water quality because of PCBs, cadmium, and other harmful substances. Other continuing pollution problems in the river include accidental sewage releases, rainwater runoff from cities, heavy metals, furans, dioxins, pesticides, and polycyclic aromatic hydrocarbons (PAHs).
Geographic scope
In addition to the main river of the Hudson River, several smaller rivers that flow into it have poor water quality. These include the Mohawk River, Dwaas Kill, Schuyler Creek, Saw Mill River, Esopus Creek, Hoosic River, Quaker Creek, and Batten Kill. The water quality issues in these rivers may involve different pollutants than those found in the main Hudson River. Many lakes located within the Hudson drainage basin are also listed as having poor water quality.
Types of pollution
Many chemical factories along the Hudson River made PCBs to use as insulating and cooling liquids in transformers, capacitors, and electric motors. From about 1947 to 1977, General Electric (GE) released 1,300,000 pounds (590,000 kg) of PCBs into the river. These PCBs came from two capacitor factories owned by GE in Hudson Falls and Fort Edward, New York. Most of the PCBs in the river were made by Monsanto Co. under the names Aroclor 1242 and Aroclor 1016. Scientists did not fully study this pollution until the 1970s. By that time, the largest factories in the area were still owned by GE.
In 1979, the U.S. Environmental Protection Agency (EPA) stopped the production of PCBs. In 1984, the EPA labeled a 200-mile (320 km) section of the river as a Superfund site because of the pollution. GE was mainly responsible for cleaning up the PCBs. The highest amounts of PCBs were found in the Thompson Island Pool.
General Motors, which operated a factory in North Tarrytown, New York, released lead chromate and other chemicals used for painting, cleaning, and soldering into the river. Waste from homes was sent to the village’s sewage treatment plant. Around 1971, the village’s Sewer and Water Superintendent said pollution reports were exaggerated and claimed that he and others swam near a local beach. However, Dominick Pirone, an ecologist and former director of the Hudson River Fishermen’s Association (now Riverkeeper), said, “You can tell what color cars they are painting on a given day by what color the river is.”
The Hudson River contains many “micro-organics,” which are small amounts of medicines and pesticides. Examples include gabapentin, metolachlor, and sucralose.
In 1991, zebra mussels, an invasive species, were first found in the Hudson River. These mussels caused native pearly mussels to nearly disappear.
Effects
In 1976, the New York State Department of Environmental Conservation (NYSDEC) stopped all fishing in the Upper Hudson River because of health risks from a chemical called PCBs. It also warned people not to eat fish caught in a 20-mile (30 km) section of the Hudson River between Hudson Falls and Troy.
Fish warnings from the New York State Department of Health (DOH) were still in place in 2022. DOH advises people not to eat any fish caught between the South Glens Falls Dam and the Federal Dam at Troy. Women over 50 and children under 15 are not allowed to eat fish caught south of the Palmer Falls Dam in Corinth. Others are told they can eat one to four meals of Hudson River fish each month, depending on the type of fish and where it was caught. The Department of Health says mercury, PCBs, dioxin, and cadmium are the chemicals affecting fish in these areas. In 2026, the state government eased its rules for fish caught south of the Rip Van Winkle Bridge to the river’s mouth at the Battery, allowing children and pregnant women to eat limited amounts of fish from these areas. However, fish caught between the Rip Van Winkle Bridge and the Federal Dam are still unsafe to eat because PCB levels remain high.
PCBs are linked to health problems such as brain and nervous system issues, lower intelligence, poor short-term memory, hormone imbalances, weakened immune systems, cancer, skin irritation, Parkinson’s disease, ADHD, heart disease, and diabetes. People can be exposed to PCBs by drinking contaminated water, absorbing them through the skin, eating contaminated fish or other aquatic life, or breathing in PCBs that have evaporated into the air. PCBs are especially dangerous for pregnant and nursing women, as the chemical can harm a developing fetus or affect a child through breast milk.
Cleanup
Large cleanup efforts on the Hudson River began in the 1970s. These efforts included rules for controlling wastewater pollution, reducing the amount of wastewater released into the river, and removing polluted sediment. These actions have continued into the 21st century.
In 1972, Congress passed the Clean Water Act, which created a system for controlling pollution in all surface waters nationwide. All businesses that released wastewater into the Hudson River were required to get permits from the New York State Department of Environmental Conservation (NYSDEC). These permits limited the amount of pollution that could be released. As a result, factories, power plants, and cities improved their wastewater treatment systems or made other changes to reduce pollution. One major improvement was the opening of the North River Wastewater Treatment Plant in Manhattan in 1986. Before this, 150 million US gallons of untreated sewage were released into the river each day. However, pollutants like PCBs and heavy metals that were released before these rules were put in place remained in the river's sediments.
One major cleanup effort involved removing polluted sediment from the river. This process, called dredging, is expensive and can cause PCBs to become airborne again.
In 1977–78, 180,000 cubic yards of polluted sediment near Fort Edward were removed. This site is considered one of the largest hazardous waste areas in the United States. In 1991, more PCB pollution was found near Bakers Falls, close to the former GE Hudson Falls factory, and a cleanup program was started. In 1995, a 40-mile section of the upper Hudson River was reopened for fishing, but only for catch-and-release. In 1999, contaminated soil on Rogers Island was completely removed.
In 2001, after studying PCB pollution in the river for ten years, the Environmental Protection Agency (EPA) proposed a plan to remove over 100,000 pounds of PCBs. The most polluted areas were targeted for cleanup, with over 2.6 million cubic yards of contaminated sediment removed. This was the largest river cleanup effort ever proposed. General Electric (GE) initially argued that dredging might spread PCBs, but later agreed to the plan. In 2002, the EPA ordered GE to clean up a 40-mile section of the river. The EPA also announced that 2.65 million cubic yards of contaminated sediment in the upper Hudson would be removed.
GE began removing contaminated sediment in 2009. In the first phase of the cleanup, about 283,000 cubic yards of sediment were removed. Over 620 barges carried the sediment to a processing facility on the Champlain Canal, and over 80 rail cars transported the sediment to a waste facility in Texas. Phase One removed more sediment than planned, so Phase Two was expanded. In 2010, GE agreed to a second cleanup campaign between Fort Edward and Troy. The EPA supervised these efforts. Phase Two, led by GE and monitored by the EPA, was completed in 2015. It removed about 2.5 million cubic yards of PCB-contaminated sediment from the 40-mile section of the upper Hudson. After the cleanup, aquatic plants were planted, and efforts to restore the river's habitat began. As of 2025, GE reported that the cleanup cost $1.7 billion.
After the cleanup, ongoing activities will continue for many years. These include monitoring water quality, testing sediment, tracking fish populations, observing habitat health, and maintaining facilities.
Although progress has been slow, environmental groups have raised awareness about the river's pollution. Organizations like Scenic Hudson, Hudson River Sloop Clearwater, Hudson Riverkeeper, and the Natural Resources Defense Council have urged GE to take more action. After Pete Seeger’s death in 2014, EPA Regional Administrator Judith A. Enck praised his work with the Clearwater organization.
Local community groups helped create Riverkeeper, a nonprofit organization that later became part of the global Waterkeeper Alliance. The Hudson River Sloop Clearwater is another group focused on protecting the health of the Hudson River.
Water quality improvement
A 2020 report on the health of the Hudson River states that "Water quality in the Hudson River Estuary has greatly improved since 1972 and has stayed mostly the same in recent years." The health of ecosystems like tributaries and wetlands shows different conditions.
A 2008 study found that mercury levels in common Hudson River fish, such as striped bass, yellow perch, largemouth bass, smallmouth bass, and carp, decreased a lot over the past 30 years. This conclusion came from a large collection of data on mercury levels in fish fillets gathered by NYSDEC from many parts of the Hudson River, including areas near New York City and the Adirondack watershed. These trends matched the river’s recovery over the past few decades, which happened because activist groups, government officials, and industry worked together to clean up the river system.
In 1980, Consolidated Edison (Con Ed) agreed to stop its 17-year effort to build a pumped-storage hydroelectricity facility on Storm King Mountain after a legal challenge by the nonprofit environmental group Scenic Hudson.
The Indian Point nuclear plant, which was harmful to aquatic life, permanently closed on April 30, 2021.