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Transparency Watch: More Data, Stricter Regulations Needed to Reduce Benzene Exposure in Mon Valley

Updated: Jul 27, 2023

The U.S. Environmental Protection Agency announced its decision to list benzene as a hazardous air pollutant under Section 112 of the Clean Air Act on June 8, 1977, based on reports “strongly suggest(ing) an increased incidence of leukemia in humans exposed to benzene.”

Despite more than 40 years of regulations and research highlighting the danger of exposure to benzene, EPA’s Toxic Release Inventory data show U.S. Steel’s Clairton Coke facility was still able to emit over 30,000 pounds of this toxic pollutant in 2018, making it far and away the largest stationary source in Allegheny County.

While raw benzene emissions are down significantly from the levels first reported in the 1970s and ‘80s, risks remain. Levels of benzene in the ambient air measured just outside South Allegheny High School–the location of the Allegheny County Health Department’s Liberty Monitor–suggest public health could be at risk. U.S. Steel must begin working with the Allegheny County Health Department (ACHD) to increase monitoring and reduce emissions.

In May of 2018—months before a fire at U.S. Steel’s Clairton Coke Works knocked out crucial pollution control systems at the facility—ACHD officials announced at a Board of Health meeting that they were planning to revise the county’s pollution control regulations covering coke oven emissions.

GASP supported the plan and expected tougher regulations would lead to reduced benzene emissions from the coke facility, as well as reductions in emissions of fine particulate matter (PM2.5) and other gasses such as hydrogen sulfide (H2S). In fact, GASP just this month held a press conference calling on ACHD to do what it promised all those months ago—and even presented a petition with the signatures of nearly 650 people imploring the county to get a handle on the tell-tale rotten egg odor caused by H2S emissions.

Meanwhile, a series of enforcement orders issued by ACHD to U.S. Steel starting in the second half of 2018 appeared to confirm the notion that tougher measures were needed to protect local communities from coke oven emissions. Addressing air quality in an interview after issuing one of those orders, ACHD Deputy Director of Environmental Health Jim Kelly told reporters that “following decades of decline, the Liberty monitor’s PM2.5 readings began increasing in 2014, primarily due to fugitive emissions from the Coke Works.”

Kelly also noted that those “fugitive emissions” – untreated emissions that do not come from a smokestack – are composed of a number of hazardous and cancer-causing air pollutants, including benzene, toluene, and ethylbenzene. He admitted that benzene emissions in particular were “very significant,” and “something we should be concerned about.”

Shortly after this interview, a fire on Christmas Eve at the Clairton Coke Works and its aftermath shifted ACHD’s focus away from regulatory reform and toward more pressing issues associated with increased emissions from the plant.

Now that operations at the Clairton facility appear to be back to normal, GASP investigated the state of the regulatory revisions proposed more than a year and a half ago, as well as data quantifying the impact of coke oven emissions.

First, the good news: While there is no EPA requirement to monitor benzene near coke facilities, ACHD—to its credit—does so at its Liberty Monitor site, which is a little over a mile northwest of, and typically downwind of, Clairton Coke Works. In addition, ACHD began monitoring for benzene and other toxic gasses at its West Mifflin monitor site after U.S. Steel began burning off (“flaring”) excess coke oven gas earlier this year at its Irvin Works in Dravosburg.

The bad news begins with the fact that ACHD does not provide benzene monitoring data in the same transparent, timely manner as it does for other data on air contaminants such as PM2.5, H2S, and sulfur dioxide (SO2).

ACHD’s benzene monitoring method does not provide real-time results; laboratory analysis is required. But even when the analysis is complete, the Department does not publish benzene monitoring results on its website. This means members of the public who wish to review that information must formally request it through the County’s Right to Know process.

More troubling is that the time for benzene data delivery from the lab to ACHD often involves months of delay, meaning the most “current” benzene data is months old.

Most troubling of all—the worst of the bad news—is that the Liberty Monitor data show concentrations of benzene well below Occupational Safety and Health Administration limits (workplace safety levels), but still above acceptable risk levels for ambient air.

As the graph indicates, the average benzene concentration at the Liberty Monitor has been very close to 1 part per billion (ppb) over the past year. The EPA has calculated this level to potentially cause one in 100,000 excess cases of cancer, but the World Health Organization states that as a carcinogen, “no safe level of exposure (to benzene) can be recommended.”

U.S. regulators also calculate a level of exposure they expect to cause no appreciable risk of an adverse health outcome. These “non-cancer” effects include a reduced red blood cell count as well as other adverse impacts on the immune and developmental systems. The table shows only the U.S. Agency for Toxic Substances and Disease Registry’s values as an example.

While the several agencies agree long-term exposure to concentrations below 1 ppb are unlikely to have non-cancer effects, the table shows ATSDR believes exposure to levels at or above 9 ppb for even one day could be harmful. The graph shows a benzene concentration of 12.74 ppb at the Liberty Monitor this past December.

Such results are concerning, and perhaps even more so considering that benzene is not monitored every day at the Liberty Monitor. In fact, ACHD only samples for benzene from midnight to midnight every third day. That means there is no data for the benzene concentrations on the two days between the graphed results.

It’s also important to understand that technical or other factors such as a power outage can occasionally render samples invalid.

Consider this: There were 118 calendar days and 40 expected sampling days from Dec. 19, 2018 through April 15, 2019 – roughly the period that pollution-control equipment was out of service at Clairton Coke due to the Christmas Eve fire. Over this nearly four-month period, monitoring data only showed 32 valid results. Although none of these results showed a concentration over 9 ppb, we can only say for sure that a little over 27 percent of the days in that time frame were below 9 ppb.

Also, as with any monitor, the data only represents a concentration at one point on a map. Thus, it can only detect what the wind or local air currents bring past that site. As noted above, Clairton Coke emits thousands of pounds of benzene annually, but the Liberty and West Mifflin monitors might not show the highest concentration that communities are being exposed to if a strong wind is blowing in a direction away from those monitors.

Toxic air pollutants are an issue in every metropolitan area of this country and even in rural and suburban areas, the presence of heavy traffic or an industrial site could be a cause for concern. Allegheny County is no different in this respect, but unfortunately, the data show one area of the County is more affected than most: the Mon Valley

ACHD measures benzene and other toxic air pollutants at three sites in the County: Avalon Borough, downtown Pittsburgh, and at Liberty Monitor. Without variation, the Liberty Monitor shows the highest readings.

The 2018 Allegheny County Air Quality Annual Report posted to the ACHD website earlier this month indicates the annual average benzene concentration in downtown Pittsburgh at Flag Plaza was 0.37 ppb. The graph shows—and ACHD’s Report confirms—that over the same period, benzene barely registered in Avalon but was 0.96 ppb at the Liberty Monitor.

The takeaways? Monitoring data near the largest source of benzene in Allegheny County consistently show that benzene in the ambient air near that facility is the highest in the county. Data also show improvements over the past several years, but there’s continued cause for concern.

Several questions remain unanswered. Chief among them: How much longer will Mon Valley residents be subjected to this—and numerous other public health issues—that can reasonably be attributed to emissions emanating from U.S. Steel’s Clairton Coke Works?

And if U.S. Steel won’t voluntarily clean up its act, ACHD must exercise its authority to force the company’s hand and require it to adhere to stronger regulations, enforcement efforts and sanctions that truly penalize noncompliance—but will it?

Several things are certain: ACHD can—and should—make this benzene data more easily accessible to the public—and in a timelier fashion. Because all of Allegheny County, including the Mon Valley, have a right to know what’s in the air they breathe.

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