Seal of Testing Assurance (STA)


If it isn’t STA Certified Compost, what is it?

The question posed above may, at first glance, appear to be a bit silly. However, if you are seriously thinking about making compost, specifying compost or purchasing compost, you want to know exactly what you are purchasing? The US Composting Council’s Seal of Testing Assurance Program (‘STA’) is a compost testing, labeling and information disclosure program designed to give you the information you need to get the maximum benefit from the use of compost.
The program was created in 2000 and is the consensus of many of the leading compost research scientists in the United States. There was no other compost testing program available to compost producers or compost buyers that give you this type of information.

The science behind the development of the STA Program and the various tests that are used is contained in ‘Test Methods for the Examination of Composting & Compost’ (‘TMECC’). This publication includes a suite of physical, chemical and biological tests. These were selected to help both compost producer and purchaser to determine if the compost they are considering is suitable for the use that they are planning, and to help them compare various compost products using a testing program that can be performed by a group of independent, certified labs across the country and in Canada.

The information contained in this area of the USCC website will provide you with a thorough explanation of all of the ‘what’s and why’s’ of the STA Program and will help you get started in enrolling your compost product.

How does the STA program work?

Key Elements of the STA Program

  • First and foremost a Participant’s composting facility must certify that it is in compliance with all applicable local, state, and federal regulations with respect to the certified compost product(s) and it must remain compliant to remain in the STA Program
  • All enrolled manufacturers or marketers (“Participants”) will regularly sample and test their compost products based on production volumes, or as otherwise prescribed by the STA program administrators for each facility they enroll
  • Participants will complete test analyses for the compost properties listed below. Also, any and all testing required by applicable State and/or Federal regulation (e.g., pathogens, heavy metals, pesticides, inerts, etc.) to assure public health/safety and environmental protection must be completed at the frequency so regulated. It is not necessary to provide laboratory analysis for particle size. The participant must simply report the screen size in which the product passes during screening. Download the STA Sample Collection Protocol & STA Chain of Custody Form [pdf]
  • All lab analyses will be conducted at ‘approved laboratories’ which have certified that they are capable of performing the test methods specified in the Program Rules. A current list of approved program laboratories can be found by clicking on “Lab” on the left hand menu. Test methods used in the Seal of Testing Assurance program are found in the Test Methods for the Examination of Compost and Composting Manual (TMECC), jointly published by the USDA and the USCC (2002 publishing as a part of the USDA National Resource Conservation Technical Bulletin Series).
  • The Participants, or their compost testing lab, will provide the appropriate lab analyses results (and updated Compost Technical Data Sheet) to the USCC at the prescribed frequency. This data will not be distributed to compost customers by the USCC. This responsibility lies solely with the program Participants.
  • All Participants will make test results available to any person, upon request, using the STA Program’s “Compost Technical Data Sheet”. The Compost Technical Data Sheet includes directions for product use, a list of product ingredients and analytical test results. The USCC will not assess whether or not, or to what extent, these directions are appropriate; this is solely the responsibility of the Participant.
  • A Participant’s composting facility must certify that it is in compliance with all applicable local, state, and federal regulations with respect to the certified compost product(s) and it must remain compliant to remain in the STA Program.
  • The USCC will certify an applicant’s compost product on the basis of the criteria specified in the “Program Rules”, allowing Program involvement with respect to the approved product, and use of the STA Program Logo, promotional opportunities, etc. If a compost manufacturer or marketer represents multiple facilities, the compost product from each individual facility requires separate enrollment in the Program. Where more than one compost product (significantly varied feedstocks) is produced at a given facility, each individual compost product must be enrolled in the Program. However, products that are simply re-screened or further aged (cured) to produce addition products, are not required to be enrolled separately
  • Participants will pay an annual STA Program application fee of $800 per product. Participants who are USCC members will receive an application fee discount of $200 per product ($600). This discount reflects the extent to which USCC members’ dues underwrite the development and management of the STA Program. Both fee schedules listed above are for the initial STA product enrolled in the Program. Enrollment of additional products is $275/yr. for the 2nd product enrolled by a USCC member, or $375 for non-USCC members.
    See STA Fees page here.
  • Participants have the right to use the STA Program Logo in their promotional activities, with respect to certified compost product(s), as long as they stay compliant with the program rules. (Composts produced from yard trimmings, manure, or food residuals may test for pathogens and trace metals at half the required frequency)

Required Customer Information

Information to be placed on the product bag or literature, or by using the Seal of Testing Assurance’s Compost Technical Data Sheet:
The Seal of Testing Assurance logo, accompanied by the following written statement:
“This compost product has been sampled and tested as required by the Seal of Testing Assurance Program of the United States Composting Council (USCC). Test results are available upon request by calling (Licensee Name) at (Telephone Number). The USCC makes no warranties regarding this product or its contents, quality, or suitability for any particular use.”

  • Directions for product usage.
  • An ingredient statement

NEW STA QR code for use on all of your promotional material

Compost Testing Frequency Table

The initial frequency of testing required by Participants is based on the volume of compost produced annually, per facility. See STA Sample Collection Protocol & STA Chain of Custody Forms below

Compost Quantity *************************    Frequency
1 – 2500 tons *******************************   1 per quarter (or less)
2501 – 6200 tons ***************************   1 per quarter
6201 – 17500 tons **************************  1 per 2 months
17501 tons and above ********************** 1 per month

Certified Compost Products will be analyzed for the following properties

soluble salts
nutrient content (total N, P2O5, K2O, Ca, Mg)
moisture content
organic matter content
bioassay (maturity)
stability (respirometry)
particle size (report only)
pathogen (Fecal Coliform or Salmonella)
trace metals (Part 503 regulated metals)

To receive STA contract forms and documents, please contact:
Hilary Nichols,  Market Development Coordinator

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