Pollution, Fires, and Explosions: Life in the Petro Metro

Large pollution events and other accidents are a constant reminder that as Houstonians, we live in one of the busier petrochemical-industrial complexes in the world. Sometimes, because Houston is so large and these events are so regular, they go almost completely unnoticed. This week we’re providing details about two recent events in the area.

Shell Deer Park Refinery releases 163+ tons of 1,3-butadiene

On Sunday, August 9, the Shell Oil Refinery in Deer Park quietly reported a release that included more that 163 tons of 1,3-butadiene, a known human carcinogen. I say “quietly” because this massive toxic release was largely unnoticed until an anonymous tipster apparently reported it to the Houston Chronicle, which reported on the event that Wednesday.

As I told Houston Public Media‘s Dave Fehling last week, even a large release of 1,3-butadience over a short period of time–as 163 tons in under an hour–might not be detected by members of the public. Butadiene is a colorless gas, and its odor threshold is rather high at 1.6 parts per million. Fortunately, the short-term air monitoring comparison value for 1,3-butadiene–a level of concern set by the Texas Commission on Environmental Quality–is also high at 1.7 parts per million.

Butadiene also degrades rather quickly in the environment. There are no toxics air monitors within or adjacent to the Shell Plant. One of the closer monitors, the Lynchburg Ferry site, did monitor a spike of butadiene of 34.20 ppb at noon on Sunday–just an hour after the release ended. (You can look up toxic air monitoring data here–call us for assistance.)

The lack of monitoring data–and the lack of public reaction–may indicate that this release was a near miss without any truly negative pubic health consequences. But it is difficult to say without more data. As Shell “quietly” discovered and  repaired the leaky storage tank valve that led to this release, it also failed to comply with an injunction that required it to report any pollution releases promptly to Harris County. When I spoke to Harris County officials about the incident, they told me that if they had been notified sooner, they would have conducted spot monitoring in the area to determine if any public hazard was present. Because Shell did not notify Harris County in the time it should have, that opportunity was lost.

It also must be said that the fenceline monitoring requirement in EPA’s proposed Refinery Rule would not have provided information or insight into this event. First, EPA has only proposed to monitor for benzene–not butadiene–at refinery fencelines. Second, EPA is collecting only two-week passive samples. Because the samples are two week averages, they will miss hourly spikes such as the one caused by this event. Because the samples are passive, their data will be reported only after a two week sampling period has concluded and laboratory analysis has occurred.

So even EPA’s new Refinery Rule proposal would not have alerted the public to Shell’s quiet release. Only the sort of monitoring we advocate for–multi-pollutant, active, real-time monitoring with public available data–could have informed Shell’s neighbors and regulators in due time. Without such monitoring, we will have to rely on tipsters and alert members of the public.


The Harris County Attorney’s office agrees with our assertion of the need to continuous, real-time fenceline monitoring. They agree that such monitoring would have provided a greater opportunity for public health officials to respond to the Shell Deer Park emissions event. Specifically, County Attorney Vince Ryan had this to say:

“The entire incident lasted about an hour. Accordingly, by the time the emission event was reported to Harris County Pollution Control Services Department (HCPCSD), HCPCSD was unable to conduct any testing in the area to determine if there were impacts to the neighboring community. Had real-time continuous fenceline monitoring been in place, all entities would have had a better awareness of the potential for any off-site impacts and been better situated to make public health decisions.

“Accordingly, the HCAO re-urges the EPA to consider the real time monitoring fenceline recommendations made by this office and other well informed entities, such as the Air Alliance Houston.”

You can read the full text of the letter by Harris County Attorney Vince Ryan to Janet McCabe, Acting Assistant Administrator Office of Air and Radiation, at the link below.

2015.08.21 Letter to EPA

Conroe Chemical Plant Explosion and Fire

Five days later and 50 miles away, a chemical company in Conroe, TX suffered an explosion and fire in which thankfully no one was injured. DrillChem Drilling Solutions is a petrochemical company that produces products for the oil and gas industry that include “shale inhibitors, lubricants, and sealants.”

DrillChem did not have the benefit of silence or invisibility, as a shelter-in-place order was issued for residents living within two miles of the fire and the resulting plume of smoke was visible for miles. According to the Houston Chronicle, assurances from DrillChem itself seem to have come practically as the blaze was still being fought. DrillChem CEO Brendan Hayes is quoted as saying, “Early indications show that there was no impact to the surrounding environment, but the health and safety of our employees and neighbors is our highest concern and we are taking every precaution.”

It’s hard to know what “no impact to the surrounding environment” means for an explosion and fire that lasted for hours and was visible for miles. Certainly citizens who were warned to stay indoors would agree that their environment had been impacted. As would anyone who had smoke, soot, or other debris landing on their property.

If you didn’t hear about this fire–or the Shell release–perhaps you feel your environment wasn’t impacted. Certainly some people will. Others will worry that we live in a city that is perhaps too used to fires and chemical releases. Maybe there weren’t any “impacts” this week, or last, but how many more weeks do we have?