Monitoring Shows Plumes of Carcinogenic Formaldehyde in Neighborhoods Along Houston’s Ship Channel

Houston Health Department Documents Air Pollutant Largely Formed in Atmosphere by Reaction of Emissions from Petrochemical Plants

For an English-language version of the report, click here. For a Spanish translation of the executive summary, click here.

HOUSTON — Air pollution monitoring by the Houston Health Department in 2019 and 2020 recorded levels of formaldehyde, a known carcinogen, along the Houston Ship Channel that pose potential health risks to largely Hispanic and high-poverty neighborhoods.

The analysis, funded by the U.S. Environmental Protection Agency, found that from September 27, 2019, to September 26, 2020, formaldehyde concentrations at three monitoring sites exceeded EPA’s health screening level of 0.17 parts per billion, meaning that local residents faced an increased risk of cancer.

While experts have known for decades that neighborhoods along the Houston Ship Channel face increased cancer risk from a toxic mixture of air pollutants from industry and traffic, the recent data confirm that cancer risk in certain Houston neighborhoods is driven in large part by formaldehyde, according to the report “Formaldehyde Air Pollution in Houston,” by One Breath Partnership in collaboration with the Houston Health Department. The partnership includes Environmental Integrity Project, Air Alliance Houston and other groups working to reduce air pollution in the Houston region.

“Formaldehyde is an emerging chemical of concern in Houston, and these new data should be valuable to the Texas Commission on Environmental Quality and EPA to help them strengthen air pollution regulations and controls to better protect public health,” said Loren Hopkins, Chief Environmental Science Officer with the Houston Health Department, who led the research effort.

“This report is more proof of the unacceptable fact that high-poverty communities of color bear the brunt of toxic pollution that sickens and kills throughout generations,” said Houston Mayor Sylvester Turner. “TCEQ has the responsibility to take immediate action to strengthen its existing rules to address the formaldehyde problem plaguing families near the Houston Ship Channel.”

The Health Department’s highest measurements were in the Cloverleaf neighborhood, where monitoring averaged 2.28 parts per billion of formaldehyde – more than 13 times EPA’s health screening level. In the long-term, this would translate to about 1 additional cancer case per 77,000 people, according to the Houston Health Department’s assessment of EPA’s cancer risk formulas. Other at-risk communities include Harrisburg, Manchester, Meadowbrook, Allendale, Northshore, and Galena Park.

Ilan Levin, Texas Director of the Environmental Integrity Project, said: “State and federal environmental regulators have the tools and the know-how to better control not just formaldehyde, but the combined impacts of a toxic cocktail of air pollutants from Houston’s petrochemical industries. For too long, Houstonians’ health has taken a back seat to Texas’ polluter-friendly policies. The communities most affected need better safeguards and a bigger seat at the table.”

Formaldehyde is a colorless, flammable gas to which brief exposure can cause irritation of the skin, eyes, nose, and throat.  It also contributes to ground-level ozone, which can cause damage to the lungs and increased rates of cardiac arrest and asthma.

Long-term exposure to formaldehyde can cause certain types of cancers. While formaldehyde is regulated for its use in construction materials and household products, elevated levels of ambient, or airborne, formaldehyde in urban environments remains a public health threat.

Most of the formaldehyde along the Houston Ship Channel originates from chemical reactions involving formaldehyde precursors that are predominantly emitted from the petrochemical industry, according to the One Breath Partnership report. Less than five percent of the formaldehyde present in Houston’s air is emitted directly from industrial point sources, and about four percent is from vehicle emissions.

Secondary formaldehyde (i.e., not directly emitted but formed by the combination of other air chemicals in the air) makes up more than 90 percent of all the formaldehyde present in Houston Ship Channel neighborhoods. Formaldehyde precursors – the gases that form into formaldehyde in the atmosphere – include ethylene, propylene and other volatile organic compounds.

Below are lists of the largest emitters of these formaldehyde precursor gases in the Houston area:

Top 10 Harris County Ethylene Emissions Sources

Company Site Annual Ethylene Emissions 2017 (Tons)
Ineos USA LLC Polyethylene Plant 25.1
Flint Hills Resources Ethylene Pipeline Equipment 24.0
Flint Hills Resources Ethylene Pipeline Equipment 22.6
ExxonMobil Pipeline Co Bop Meter Station 21.6
Chevron Pipeline Company TXF633 Induroma Meter Station Pipeline 20.9
Chevron Phillips Chemical Company LP Pasadena Plastics Complex 19.3
Chevron Phillips Chemical Company LP Pasadena Plastics Complex 19.3
Ineos USA LLC Polyethylene Plant 19.1
Equistar Chemicals LP La Porte Complex 18.3
Equistar Chemicals LP La Porte Meter Sites 17.8

Source: 2017 data obtained from the State of Texas Air Reporting System (STARS) on March 8, 2019.

Top 10 Harris County Propylene Emissions Sources

Company Site Annual Propylene Emissions 2017 (Tons)
ExxonMobil Chemical Company Baytown Chemical Plant 31.7
ExxonMobil Chemical Company Baytown Chemical Plant 27.2
Equistar Chemicals LP Bayport Polymers 25.7
ExxonMobil Chemical Company Baytown Chemical Plant 21.4
Ineos USA LLC Polyethylene Plant 18.5
Shell Chemical LP Deer Park Plant 18.2
Ineos USA LLC Polyethylene Plant 15.8
ExxonMobil Chemical Company Baytown Olefins Plant 13.4
ExxonMobil Chemical Company Baytown Chemical Plant 12.9
Braskem America Inc La Porte Plant 12.8

Source: 2017 data obtained from the State of Texas Air Reporting System (STARS) on March 8, 2019.

The report, “Formaldehyde Air Pollution in Houston,” makes the following recommendations:

  • While formaldehyde is regulated as a hazardous air pollutant under the federal Clean Air Act, new regulations and mechanisms—such as stronger permits—are needed to reduce the chemicals such as ethylene and propylene that are emitted from industrial sources and lead to secondary formaldehyde formation.
  • TCEQ should exercise its existing authority to address formaldehyde precursors in at least two ways. First, TCEQ should amend and strengthen its Highly Reactive VOC rules, 30 Texas Admin. Code Chapter 115, which are geared at reducing ozone precursors in the Houston area. In addition, TCEQ has the existing authority to adopt new rules to protect the public from cumulative risks in areas of concentrated operations. This authority to address cumulative risks gives TCEQ ample ability to reduce formaldehyde precursor emissions along the Houston Ship Channel.
  • Until such time as TCEQ strengthens its existing rules to address the formaldehyde problem, agency permit reviewers should ensure that Houston area industrial sources limit their emissions of formaldehyde precursors in the areas hit hardest by formaldehyde air pollution.

One Breath Partnership is a nonprofit, nonpartisan coalition that elevates work for clean air in Houston, Harris County and the surrounding region. The founding members of One Breath Partnership are Air Alliance Houston, Environment Texas, Environmental Defense Fund, Environmental Integrity Project, Public Citizen, and Rice University. Our work is made possible through the Houston Endowment.

Media contacts:

Tom Pelton, Environmental Integrity Project, (443) 510-2574 or
Scott Packard, Houston Health Department, (281) 254-6403 or
Matt Tresaugue, One Breath Partnership, (713) 392-7888 or