July 2019

Triangle NoTES

July 2019

Recently I was looking into Tier II reports in the public domain to see how the “doughnut hole” nitrogen correction affected the reported NMOC results. Although that impact is still a big concern, especially for the landfill operators, the thing that flagged for me was something I had thought had been put to rest years ago. The illegal shipment of landfill gas samples back to the laboratory became very evident in the review of the reports. One report in particular documented the violation so well I am sure the US DOT could issue the citations from it if they were so inclined and there was not a statute of limitations which had been exceeded.

As a result I am mentioning it in this newsletter and also sending a copy to each state agency for which I can find a contact email. This is so the review of any proposed protocols would not give some indirect approval of the illegal shipment.

According to the US DOT regulations for shipping non-pressurized gas samples, which are classified as flammable, the container must be less than five liters in volume. Pure landfill gas is classified as flammable according to the formula specified in the US DOT regulations. The only way to bypass the flammability issue is to dilute the sample to where the concentration of methane falls below the limit using the previous formula. If the sample is not classified as flammable it can be shipped in any sized container by any means. If the sample is classified as flammable the shipping limitations must be met and the proper documentation has to be provided for the shipment, which is time consuming and expensive.

We have always partially filled the canister with helium prior to shipment so the return of the samples would not normally be classified as flammable. This allows us to use many different sizes of canisters without a problem. We also rely on the use of a 4.5L canister in case there was any issue with sampling that would negate our helium pre-charge. If this happened we could still have the sample legally shipped back to us as a flammable shipment. I only remember one case where this occurred and it was a significant problem. There had been some samples taken from a compressor station and they had accidentally been taken from the wrong port and were filled to 60 psi before anyone knew. To ship legally all we had to do was to measure the final pressure and then release it down to atmospheric before shipping as a flammable shipment.

Now, to look at what caught my eye with the other report. There was listed a specific number of sites from which samples were to be taken, which is a maximum of 50 for a landfill. These were going to be composited in the field which is not uncommon, but the number of samples for analysis was uncommon. There were only ten data points, which meant there were five samples composited into one container. As the requirement for a valid composite sample is a minimum of 1L, this could have barely been legal if there had been a 5L canister used. Unfortunately the report documented there was 5 inches Hg of vacuum left in the Summa canister used. This indicates a common 6L Summa canister was used, which exceeds the volume requirement specified by the US DOT. Some people have tried to claim they are legally shipping the sample because there are only five liters of sample in the canister at ambient pressure. The problem is that a gas expands to fill the size of any container so there are six liters of gas at a lower pressure in the canister. The US DOT understands this so that is not a valid defense for the violation.

The report also documented that the canisters were shipped via cargo aircraft with the dates and even tracking numbers. Even though it is just as illegal to ship flammable gases over the highways the critical nature of an aircraft's integrity seems to add to the enforcement concerns over such a shipment.

In any case, these are considered serious violations by the US DOT, which is why I have worked with them to ensure that we prepare the canisters for our clients correctly to prevent as many potential issues as possible. I do not know how probable it is for anyone to be caught illegally shipping flammable gases, but I have heard that is is very expensive when someone is caught. I am told they consider each canister a separate violation and people have been fined tens of thousands of dollars. I think any fine such as that would ruin someone's day if not their continued employment potential.

The other defense I have heard used for such a shipment was that they were required to sample and ship in that manner based upon some aspect of the permit, approved protocol, or regulatory requirement. This would not have been an issue if the original shipping requirements had been left in the methods as that should have clarified the regulatory position.

With this in mind I would like to point out some of the red flags in a protocol.

Compositing more than four sample locations into one canister is a big warning flag. Four composites can be done with 4.5 L canisters and shipping as flammable. This can also be done with 8L canisters which are pre-charged with helium and are shipped as non-flammable. Anything over four composites would be a very unusual sized canister with a pre-charge. A 6L Summa canister will get three samples composited but with a minimal vacuum left after sampling the 1L fractions.

No matter what volume of sample to be taken at atmospheric pressure, if the container is over 5L in volume there can be no legal shipment unless the canister is correctly pre-charged. If the container is 5L or less it can be legally shipped as a flammable gas shipment. If the canister is properly pre-charged any size can be used and shipped normally.

Also, unless someone from the US DOT gives instructions on shipping a larger volume without the correct pre-charge and will provide the appropriate documentation, do not listen to them. Any advice given which is contrary to the specific regulations and basic science can cause problems for the shipper. The adviser is protected because it is the responsibility of the shipper to ensure all of the regulations are followed accordingly.

Wayne Stollings

Triangle Environmental Services, Inc.


P.O. Box 13294 122 US Hwy 70 E

Research Triangle Park, NC 27709 Hillsborough, NC 27278

(919) 361-2890 (800) 367-4862 Fax: (919) 361-3474