https://theconversation.com/air-pollution-from-industrial-shutdowns-and-startups-worse-than-thought-91361
[images and links in on-line article]
Air pollution from industrial shutdowns and startups worse than thought
February 14, 2018 6.38am EST
When Hurricane Harvey struck the Texas coast in August 2017, many
industrial facilities had to shut down their operations before the storm
arrived and restart once rainfall and flooding had subsided.
These shutdowns and startups, as well as accidents caused by the
hurricane, led to a significant release of air pollutants. Over a period
of about two weeks, data we compiled from the Texas’ Air Emission Event
Report Database indicates these sites released 2,000 tons of sulfur
dioxide, carbon monoxide, nitrogen oxides, volatile organic compounds
and other pollutants.
These types of emissions that result from startups, shutdowns or
malfunctions are often referred to as “excess” or “upset” emissions and
are particularly pronounced during times of natural disasters, as was
the case with Hurricane Harvey.
However, as we document in a newly published study in the journal
Environmental Science & Technology, they also occur regularly during the
routine operation of many industrial facilities, sometimes in large
quantities. And, even if unintended or unavoidable, the pollutants
released during these events are in violation of the U.S. Clean Air Act
(CAA).
With the EPA now revisiting the rules regarding these air toxics, our
study shows how significant they are to public health – and how
historically they have not been systematically tracked across the
country or regulated comprehensively.
Excess emissions in Texas
Our study examines the occurrence of excess emissions in industrial
facilities in Texas over the period from 2002 to 2016. We focused on
Texas because, unlike nearly all other states, it has established
comprehensive reporting requirements. The state collects data on
so-called hazardous air pollutants that cause harm to people exposed to
them, such as benzene, as well as substances called criteria pollutants,
such as nitrogen oxides that contribute to the formation of ozone.
As a general rule, states set limits to industrial air emissions based
on provisions in their State Implementation Plan (SIP), which is their
strategy for meeting CAA requirements. The EPA in turn is responsible
for ensuring that each state’s SIP is drafted in accordance with the CAA.
The CAA requires sources of air pollution to achieve continuous
emissions reductions, which in essence means companies need to install
and maintain equipment to limit the release of pollutants that happen
during routine operations.
Excess emissions occur when pollution abatement systems, such as
scrubbers, baghouses, or flares that curtail emissions before they are
released, fail to fully operate as the result of an unexpected
malfunction, startup or shutdown. That is, a facility fails to maintain
continuous emissions reductions, thereby exceeding its permit limits.
Although one might assume that such occurrences are rare, we found that
excess emissions in Texas are frequent, sometimes large, and likely
result in significant health damages for individuals living in
communities near where these emissions are released.
Specifically, there are four important takeaways from our study.
First, excess emissions represent a sizeable share of permitted (or
routine) emissions. In the case of the natural gas liquids industry,
excess emissions amounted to 77 thousand tons over the period 2004-2015,
representing 58 percent of the industry’s routine emissions for that
pollutant. Refineries emitted 23 thousand tons of excess emissions (10
percent of their routine emissions of SO2) while oil and gas fields
released 11 thousand tons (17 percent of their routine emissions of SO2).
Second, the distribution of excess emissions is highly skewed. While
thousands of excess emissions events occur every year in Texas, the top
5 percent of events release more pollutants than all the other events
combined. In extreme cases, excess emissions events can release vast
amounts of pollutants in a very short period of time. In 2003, a Total
oil refinery in Port Arthur emitted 1,296 tons of sulfur dioxide within
56 hours, due to a power outage caused by a lighting strike. That was
almost twice the amount of the total sulfur dioxide that refinery
emitted that year from its routine operations.
Third, several industrial sectors account for a disproportionate amount
of excess emissions. Facilities in just five sectors – natural gas
liquids, refineries, industrial organic chemicals, electric services and
oil and natural gas fields – emit about 80 percent of all excess
emissions from industrial facilities in Texas.
Moreover, a few facilities within each sector are responsible for the
vast majority of excess emissions. For example, the top six oil
refineries are responsible for 70 percent and 77 percent of the excess
emissions of sulfur dioxide and carbon monoxide, respectively, released
from all 30 Texas refineries.
Finally, excess emissions have important health effects. Using a model
that links pollution to mortality, we estimate that the health damages
attributable to excess emissions in Texas between 2004-2015 averaged
US$150 million annually. These estimates are certainly not comprehensive
as they only consider damages from premature mortality due to
particulate matter (PM) emissions caused by the emission of sulfur
dioxides and nitrogen oxides.
The model does not account for the direct damage from other pollutants
or from nonfatal, acute health events such as asthma attacks. As such,
our estimate can be considered a lower bound.
Beyond Texas
The data we analyzed in our study reveal the magnitude of the problem
caused by excess emissions. Yet, it is important to remember that they
only capture the situation in Texas. We know very little about excess
emissions and their trends over time at the national level. That’s
because Texas is one of just a few states (the others being Louisiana
and Oklahoma) that systematically track and make public information on
these type of pollution releases.
The Texas Commission on Environmental Quality (TCEQ) has gone as far as
to implement a system that requires facilities to publicly report excess
emissions events within 24 hours of their occurrence, information that
the TCEQ then makes available on its website.
Although Texas is unique in its reporting requirements, excess emissions
events are common elsewhere as the watchdog group the Environmental
Integrity Project, has documented in a series of reports.
Excess emissions are underregulated
The EPA, after decades of leaving excess emissions outside of its
regulatory focus, made a concerted effort to update its approach during
the final years of the Obama Administration.
Prompted by a lawsuit brought by the Sierra Club, the EPA issued a State
Implementation Plan (SIP) call in 2015, asking states to revisit the way
they regulate excess emissions. The agency found that certain SIP
provisions in 36 states were “substantially inadequate to meet Clean Air
Act (CAA) requirements.”
This means that industrial facilities may have been regularly surpassing
the limit of their permitted pollution limits, in part because of these
excess emissions. But because of state agency exemption provisions, it
could be the case that these facilities would not always be penalized.
In other words, the EPA determined that many states had, as a matter of
policy, often failed to treat excess emissions as violations and
potentially shielded offending companies from paying fines.
The EPA is now revisiting its policy as part of the Trump
administration’s broader efforts to scale back many of EPA regulations
and decisions during the Obama era. Given the frequency, magnitude, and
important adverse effects for public health, the EPA’s ultimate decision
on how states should treat excess emissions is consequential.
In addition, much is still to be learned about the magnitude of the
excess emissions problem across the country. If an effective regulatory
framework is to be designed to reduce them, it is imperative that more
states begin tracking excess emissions events in a detailed and
systematic way, following the example set by Texas.
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