Industry Violations of New Rule Almost Slid Under State's Radar

Houston-area industrial facilities have regularly violated a key air pollution regulation during the first two months it has been in effect. Their failure to comply with the new rule – which sets an hourly limit on specific emissions – places the region’s strategy for reducing ozone smog at risk. Yet the state’s environmental agency has only recently begun investigating the incidents.

From April 1 to May 31, 2006, chemical plants and refineries self-reported at least four violations of the limit (see Table 1). Furthermore, an additional 14 violations of the rule may have occurred, but the self-reported data are not descriptive enough to demonstrate whether or not a violation existed.

The new pollution limit, which was established by the Texas Commission on Environmental Quality (TCEQ) in 2004, plays a major role in the state’s plan to clean Houston’s air. Its goal is to prevent rapid formation of ozone by capping emissions of certain pollutants, known as highly reactive volatile organic compounds (HRVOCs), at 1,200 pounds per hour. The rule came into effect for Harris County in April 20061.

However, the TCEQ didn’t implement adequate procedures for investigating and enforcing violations of the rule. According to TCEQ investigation staff, all air emission events are investigated to determine if they warrant enforcement for unauthorized emissions. In response to GHASP’s inquiries in June 2006, the TCEQ has added review of this rule to its emission event investigation practices.

To prevent rapid formation of ozone smog and to reduce public exposure to toxic air pollution, we are calling on the TCEQ to develop an enforcement plan for the hourly limit that includes:

• Investigations of all 18 actual and potential violations; and
• Revisions of its air emission event reporting database to routinely collect the data needed to identify potential violations of the limit.

We are also submitting this report to the U.S. Environmental Protection Agency for its use in evaluating the potential effectiveness of the hourly limit in controlling ozone smog. While the emissions events listed in Table 1 are evidently unauthorized exceedances of the short-term cap, in other cases further information is needed to determine if a violation of the hourly limit occurred. In 14 cases, we determined that the emissions event report had sufficient information to suggest that a violation of the hourly limit may have occurred (see Table 2).

According to TCEQ investigation staff, there are no current procedures to collect the type of information that would be needed to determine compliance in these 14 cases. Such emission events could be investigated during future compliance reviews, but due to resource limitations, not all companies are reviewed for compliance on an annual basis. Furthermore, the procedures for compliance reviews have not been revised to include a specific focus on the new emissions limit.

When the rule was enacted, the TCEQ stated that, “An exceedance of [the hourly] limit is, by rule, unauthorized emissions” (see sidebar). We found that most online reports of unauthorized emissions lack sufficient information to determine if the company may have a valid affirmative defense against enforcement action.

Self-reported incident data alone may not be sufficient to determine if a violation occurred, because:

• The reports list total emissions over the complete duration of the incident, including any emissions associated with startup after a repair is completed. The report does not list the peak hourly emissions rate. For example, if 5,000 pounds of pollution are released over a 5-hour period, the peak hourly emissions rate likely exceeded 1,000 pounds per hour, but it is not certain that the 1,200 pound per hour limit was violated.
• The reports list only emissions associated with the incident, and do not include other routine emissions at the facility. Since the hourly limit applies to the entire facility, a violation could be triggered even if the emissions caused by the incident are less than 1,200 pounds per hour. For example, if an incident results in 1,000 pounds of pollution in an hour, and typical emissions across the rest of the plant are 300 pounds per hour, then it is likely that a violation occurred.
• The reports are typically based on calculated emissions, rather than measured emissions, and often omit evidence to demonstrate that the calculations meet TCEQ requirements. For example, TCEQ rules allow companies to assume 98 percent or 99 percent of chemicals sent to a flare are effectively destroyed, as long as flare operations comply with certain guidelines. If operations are not in compliance, then the companies may only assume 93 percent of the chemicals are destroyed. Some companies are assuming 98 percent or 99 percent destruction without stating that their flares were in compliance with the requisite guidelines (see sidebar). For example, suppose a company sends 20,000 pounds of butadiene to its flare in one hour. Using the 98 percent efficiency, the company would report 400 pounds of butadiene emissions for the hour. However, if the flare wasn’t operated in accordance with guidelines, the company would have to report a 93 percent efficiency, which would equal 1,400 pounds for that hour.

Until these issues are addressed through follow-up investigations and revisions to the self-reporting requirements, the TCEQ will not be able to effectively enforce the hourly limit.