Association for Public Policy Analysis & Management

We estimate the health impacts of upset emissions from criteria air pollutants and Volatile Organic Compounds (VOCs) emitted from a variety of facilities across different industries in Texas. Upset emissions (also known as accidental emissions or emissions events), are considered violations under the Clean Air Act (CAA). The EPA has delegated the authority of monitoring and enforcing those violations to the states. However, the regulatory landscape around enforcing those violations is unclear as some upset emissions can qualify for scheduled maintenance, startup and shutdown event exemptions. The Texas Commission on Environmental Quality (TCEQ) is one of the few state regulatory agencies that provides public access to upsets emissions records at the facility level dating back to 1990. Until 2003 eligible facilities were required to report annual totals of upset emissions. That year, the TCEQ introduced a rule that required all eligible facilities to report upset emissions within 24 hours of their occurrence. Upon receiving a report of an upset emission event from a facility, the TCEQ posts that information on its website making it immediately available to the public. We exploit the fact that upset emissions are both unexpected and often represent a large fraction of a firm’s annual pollution to examine the health impacts of diminished ambient air quality.

The contribution of our work is twofold. First, we provide in depth analysis of the rich upset emissions dataset from the TCEQ, which has so far received limited attention in the literature. The scale and frequency of upset emissions, particularly for certain sectors like refining and natural gas liquids, suggests that they pose important risks to human health. For example, in the period between 2000-2015 upset emissions of SO₂ represented 2% (201,000 tons) of all SO₂ emissions in Texas (The relevant numbers for CO, VOC and NOx are 4% (258,000 tons), 7% (162,000 tons) and 0.3% 26,000 tons) respectively.) The petroleum refining sector is of particular concern as it is responsible for a substantial share of those upsets. During the same 2000-2015 period, Texas refineries were responsible for 21% of all SO₂ upsets, 32% of all CO upsets, and 28% of all VOC upsets. Natural gas liquids facilities emitted 60% of all SO₂ upsets, while industrial organic chemicals facilities were responsible for 20% of all VOC upsets. Our work identifies the trends in upset emissions by industry over the years. Our second contribution lies in examining the health impacts of upset emissions. Preliminary results using an integrated assessment model, suggest that the health impacts of these upsets are valued at over $100,000,000. Further work is currently underway to link upset emissions directly to mortality. Mortality data come from the Center for Disease Control’s Multiple Cause of Death files. These restricted access data are constructed from individual death certificates and include information on each decedent’s cause of death, age, race, gender, and county of residence.