| Chemical Plant Announces Increased Butadiene Emissions in 2004
Overview
Shell Deer Park reported 162,300 pounds of 1,3-butadiene (“butadiene”) air emissions in 2004 to the Texas Commission on Environmental Quality (TCEQ). This was an increase of 139,941 pounds from the 22,359 pounds reported in 2003. The 2004 increase resulted from a change in calculating flare destruction efficiency – how completely butadiene is combusted in the flare -- and process changes that sent more butadiene to the chemical plant’s flare system.
Current and past measurements of butadiene in the local ambient air at TCEQ and Houston Regional Monitoring stations through June 2005 show a continuing decline in average annual butadiene concentrations.
Houston Ship Channel communities are as healthy as other communities in Texas and the U.S., and there are no apparent associations of cancer with any industry emissions, according to the Texas Department of Health. A TCEQ study on air quality confirmed “normal health” in ship channel communities.
What is Butadiene?
Butadiene is a raw material used to make many finished products, such as tires, paints, adhesives, home appliances, automobile parts, carpet backing, footwear and toys. The Shell Deer Park plant, other local industry and non-industry sources (e.g. vehicle exhaust, tobacco smoke) contribute to butadiene emissions. The EPA has concluded that butadiene is carcinogenic to humans by inhalation of high-level concentrations over time.
Details
At the request of the TCEQ, Shell began using a 98 percent destruction efficiency to calculate butadiene emissions from our flare system for 2004 reporting. Shell had used 99.5 percent based on Shell technical guidance. Higher efficiency equals fewer emissions. Use of the lower flare destruction efficiency resulted in higher calculated emissions of uncombusted butadiene from the flare system.
While Shell believes that its historical use of 99.5 percent destruction efficiency is technically sound, and in fact is a standard currently used at many Shell facilities around the world, we have complied with the agency’s request. There are no regulations for calculating flare destruction efficiency to determine compliance with permit requirements. Industry practice ranges from 98 – 99.9 percent efficiency.
In 2004, Shell reported approximately 100,000 pounds of butadiene emissions (calculated using the lower flare destruction percentage) from the flaring of material containing butadiene, butanes and butylenes. This material previously had been used as fuel for boilers. The boilers were shut down when Shell began purchasing steam from a Deer Park co-generation facility. (The boiler shutdowns resulted in a reduction of 5.2 million pounds a year of oxides of nitrogen (NOx) emissions from Shell Deer Park). Based on the TCEQ request, the chemical plant now uses a lower calculated destruction efficiency for the flare system than for the boilers.
Action Taken
The material containing butadiene that was being routed to the flare system now is recycled -- this change is reducing butadiene air emissions by approximately 100,000 pounds a year. Shell continues its efforts to reduce all flaring and to pursue other opportunities to recycle or recover chemicals such as butadiene so that less product goes to flares for destruction.
Shell Deer Park also is implementing projects to meet the requirements of the TCEQ’s Highly Reactive Volatile Organic Compounds (HRVOC) rules. These projects involve the installation of analyzers and meters to measure 1) the amount of butadiene and other HRVOCs that are sent to flares; and 2) the amount of butadiene and other HRVOCs in cooling water tower emissions. These projects will be completed by year-end. TCEQ rules also place a limit on all hourly HRVOC emissions from these same emission sources. The one-hour limit becomes effective on April 1, 2006. HRVOCs are compounds that have the greatest potential to contribute to the formation of ground-level ozone.
Health
The University of Texas School of Public Health has found no major differences in air quality between Deer Park and other Houston communities, and no significantly elevated levels of air toxics in Deer Park.
Community - An industry-funded air monitoring station located one-quarter mile southeast of Shell Deer Park has taken continuous readings of butadiene and other materials since the mid-1990s. Other industry sponsored and TCEQ air monitoring stations in the area likewise measure a range of materials, including butadiene, with similar low-risk readings.
Modeling of butadiene from Shell Deer Park air emissions in 2004 confirmed that one-hour and annual levels at our property boundary were below the Effects Screening Level (ESL) set by the TCEQ. Concentrations below an ESL indicate that no adverse health effects are expected, according to the TCEQ.
Workplace - Industrial hygiene monitoring of employees in job groups that meet criteria for butadiene exposure has been conducted since the early 1980s. In 1997, a butadiene medical surveillance program was initiated after OSHA set a workplace exposure standard for butadiene. Employees with potential exposure to butadiene above established limits are included in the program. Workplace improvements to limit butadiene exposure of employees and contractors include engineering controls such as vapor recovery systems, hazards awareness training, the safe work permitting process, industrial hygiene monitoring and personal protective equipment.
Results of a Shell-commissioned medical study of workers exposed to butadiene at Deer Park found no evidence of adverse hematological (blood) effects due to butadiene. Exam and laboratory data from 1979 to 2003 were analyzed.
In April 2005, an air monitoring study funded by a $200,000 Shell grant was conducted at Shell Deer Park. The 30-day study was overseen by a diverse
stakeholder group, including state and federal air regulatory agencies and non-governmental organizations (NGOs). Test results of technology developed by Cerex Environmental Services indicated that overall levels of targeted chemicals, such as butadiene and benzene, were low-risk for potential health impacts. A similar study in 1998 had the same results.
Regulatory Compliance
We take seriously our responsibility to operate in compliance with government permits and regulations. In this regard, due to the use of the lower flare destruction efficiency, we reported to the TCEQ that our annual emissions of Volatile Organic Compounds (VOCs) through the olefins flare system exceeded the existing TCEQ air permit limits for 2004. Process and permit changes have been made to correct this situation for 2005. This air permit does not specifically limit the annual butadiene emissions from the flare system. However, butadiene is a VOC and is included in overall VOC emissions. VOCs are a group of compounds that contribute to the formation of ground-level ozone.
Our Commitment
The well being of our employees, contractors and community neighbors is our highest priority. We are committed to ongoing improvement in our overall performance, especially as it pertains to protecting people and the environment. Globally, Shell Chemicals is on track for achieving a five-year goal to reduce critical air emissions, including butadiene. Shell Deer Park is a contributor to this effort through projects and improved process control.
We support independent research to understand the hazards and risks associated with exposure to butadiene, and the development of a health risk assessment. Shell actively participates in the American Chemistry Council’s Olefins Panel, for example. At the state level, we support the Texas Chemical Council’s efforts to promote science-based air regulations with the TCEQ.
Both the Shell Deer Park Chemical Plant and Shell Deer Park Refining Company earned ISO 14001 certification for their environmental management systems in 2005. We continue to commit significant resources to reducing our air, water and waste “footprint” on the environment.
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