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Eight Mile Community FAQs

Does Mobile Gas odorize its natural gas?

Yes. Natural gas, in its natural state, is colorless and odorless. Mobile Gas, like most utility companies in the United States, adds an odorant called mercaptan to natural gas for safety reasons – to make it more readily detectable.

Is Mobile Gas required to add odorant to natural gas?

Yes. Federal law (CFR-2003 Title 49, Volume 3, Section 192-625)  requires utility companies to add odorant to natural gas. The U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA) notes the following in an article Odorization: A Matter of Protection.

Odorization of natural gas is done for two reasons: First, it helps furnish an added level of safety and security to the gas system by providing a warning device for the public. It is undoubtedly the most important aspect of gas operations. We depend on odorization to protect our families and ourselves. Without this critical component, their safety could not be assured. Secondly, odorization is required by the Pipeline Safety Regulations of the Department of Transportation, in 49 CFR 192, section 192.625.

What led utility companies to begin odorizing natural gas?

On March 18, 1937, an undetected natural gas leak caused an explosion that killed approximately 293 students and teachers at the New London Consolidated School in New London, Texas. For more on the explosion: The New London School Explosion. Shortly after the incident, the Texas legislature required the use of mercaptan in gas distribution systems, and the practice spread from there.

What is mercaptan?

Mercaptan is a liquid added to natural gas that has a very strong, unpleasant odor. For more information mercaptan: Toxipedia: Mercaptans

What types of mercaptan does Mobile Gas use?

Mobile Gas purchases its mercaptan from a vendor whose product contains a combination of tert-Butyl mercaptan and Methyl ethyl sulfide. Neither compound appears on the Occupational Safety and Health Administration (OSHA) list of highly hazardous chemicals: Toxic and Reactive Highly Hazardous Chemicals  or on the Environmental Protection Agency (EPA) “List of Lists” (EPCRA/CERCLA Consolidated List of Lists March 2015).

Did Mobile Gas investigate the odor in the Eight Mile area?

Yes, Mobile Gas, in cooperation with the Alabama Department of Environmental Management (ADEM), completed an investigation in the fall of 2014 that determined the location and extent to which odorant was present in the groundwater in Eight Mile near Mobile Gas’ Whistler Junction facility.  Mobile Gas’ efforts included the following:
·         May 2012 – Mobile Gas entered into a preliminary agreement with ADEM to investigate the odor in the Eight Mile community
·         July 2012 – Mobile Gas submitted a preliminary report to ADEM detailing the findings of the initial assessment activities
·         August 2012 – Mobile Gas submitted a site assessment plan for soil and groundwater testing to ADEM; a revised plan was submitted in November, 2012
·         Fall 2012 – Mobile Gas began the first phase of soil and groundwater testing and submitted a report of the results to ADEM in January 2013
·         February – July 2013 – Mobile Gas conducted a second phase of the odor investigation, tested soil and groundwater on a different portion of the property where constituents of mercaptan were detected, and submitted a report of this work to ADEM in August 2013
·         December 2013 – Mobile Gas conducted the third phase of the investigation with additional soil and groundwater testing
·         September 2014 – Mobile Gas submitted its final supplemental site assessment report to ADEM

Was the more recent odor linked to a 2008 leak?

In June 2008, Mobile Gas issued a statement that was reported in the Mobile Press-Register (Chemical odor leak reported in Eight Mile area) indicating a line used to carry odorant leaked after being damaged by lightning. The leak was promptly reported to ADEM and the soil around the leak removed. ADEM approved the disposal plan for the soil. Residents in the Eight Mile community started reporting odor in late 2011. Mobile Gas has taken steps to eliminate the odor (see below) and completed an investigation in the fall of 2014 that determined the location and extent to which odorant was present in the groundwater (see above).

What additional steps did Mobile Gas undertake to investigate and test for mercaptan?

Since the investigation into the unpleasant odor began in the Eight Mile community, Mobile Gas, along with its outside contractors (McFadden Engineering and AECOM Technical Services), has conducted the following activities, among others:
·         Installed 99 groundwater wells on the property to test groundwater in the area
·         Collected and analyzed over 270 groundwater samples
·         Performed over 110 soil borings in the area
·         Collected and analyzed over 330 soil samples
·         Collected and analyzed more than 600 surface water samples

What steps have Mobile Gas taken to eliminate the odor in the Eight Mile community?

Mobile Gas has installed two different water treatment systems in the Eight Mile community: one to treat surface water from the springs near the old, abandoned Cochran Road; the other to treat groundwater where tert-Butyl mercaptan has been detected.

The first water treatment system was installed in October 2012 and was an air stripping with carbon filtration system.  Permanent power (electricity) to the system was installed in December 2013.  With ADEM approval, Mobile Gas upgraded the air stripping system to an ozone treatment system in September 2013.  The system captures water from the springs near the old, abandoned Cochran Road in a tank where ozone is added to the water.   Once treated, the water is released back into the environment.  As part of its continuing effort to improve the treatment system, Mobile Gas upgraded to a more robust ozone unit in August 2014.

ADEM approved Mobile Gas’ request for a second water treatment system in November 2014.  Mobile Gas submitted its implementation plan for the additional system in January 2015, ADEM approved it in March 2015, and construction of the system was completed and became operational in November 2015.  This particular system is designed to extract and treat groundwater that is not coming to the surface.  The extraction system uses wells with pumps inside to capture groundwater.  The pumps pull the groundwater from below ground where it is put into a treatment system where ozone is injected.  Once treated, it is released into the environment.

Both treatment systems are environmentally friendly and utilize the same established and reliable technology as is used in potable water treatment systems across the country.  Mobile Gas personnel physically inspect both treatment systems twice a day to make sure everything is operating correctly.  Each system is monitored remotely and Mobile Gas is notified if there are any issues.

To date, Mobile Gas has treated approximately 30 million gallons of groundwater.

Why did the investigation and implementation of the treatment systems take so long?

Mobile Gas recognizes the impact the odor has had on our community and that both the investigation and treatment efforts have taken a long time.  The area where the tert-Butyl mercaptan was detected has a complex geology and groundwater flow (sometimes referred to as hydrogeology).  Because of this, it took time to investigate and determine the source of the odor and the extent of the constituents of concern in the groundwater.  Mobile Gas needed to understand the problem before determining the appropriate solution.  In addition, throughout this process, Mobile Gas has worked with ADEM to conduct testing, undertake assessments, submit reports, and obtain the appropriate permits to build and operate its two treatment facilities.

Has Mobile Gas made reports to the ADEM?

Yes. For documents related to this matter on ADEM’s website, go to http://app.adem.alabama.gov/eFile/ and make just three entries: First, for “media area,” check the water box. Second, for “county,” select Mobile. Third, for “file name,” enter 16594.