D.C. Mun. Regs. tit. 22-C, § 6506
6506.1 Cultivation centers and manufacturers shall test all products for residual solvents and processing chemicals in accordance with this section before distributing, selling, or otherwise transferring the product to an internet retailer, manufacturer, or retailer.
6506.2 The testing laboratory shall analyze at minimum 0.25 grams of the representative sample of cannabis product or pre-rolls to determine whether residual solvents or processing chemicals are present.
6506.3 The testing laboratory shall report the result of the residual solvents and processing chemicals testing in unit micrograms per gram (µg/g) in the testing results and indicate “pass” or “fail” in the result report.
6506.4 The sample shall be deemed to have passed the residual solvents and processing chemicals testing if the presence of any residual solvent or processing chemical listed in the following tables in Category I and Category II does not exceed the indicated critical limit, except that:
(1) The critical limit for ethanol does not apply to cannabis products that are tinctures; and
(2) The critical limit for ethanol or isopropyl alcohol does not apply to cannabis products that are topical cannabis products.
Category I Residual Solvent or CAS No. Processing Chemical
Cannabis Product or Pre-Roll Critical Limit (µg/g)
| 1. 1,2-Dichloroethane | 107-06-2 | 1.0 |
|---|---|---|
| Benzene | 71-43-2 | 1.0 |
| Chloroform | 67-66-3 | 1.0 |
| Ethylene oxide | 75-21-8 | 1.0 |
| Methylene chloride | 75-09-2 | 1.0 |
| Trichloroethylene | 79-01-6 | 1.0 |
|---|---|---|
Processing Chemical
Action Level (µg/g)
| 2. Acetone | 67-64-1 | 5000 |
|---|---|---|
| Acetonitrile | 75-05-8 | 410 |
| Butane | 106-97-8 | 5000 |
| Ethanol | 64-17-5 | 5000 |
| Ethyl acetate | 141-78-6 | 5000 |
| Ethyl ether | 60-29-7 | 5000 |
| Heptane | 142-82-5 | 5000 |
| Hexane | 110-54-3 | 290 |
| Isopropyl alcohol | 67-63-0 | 5000 |
| Methanol | 67-56-1 | 3000 |
| Pentane | 109-66-0 | 5000 |
| Propane | 74-98-6 | 5000 |
|---|---|---|
| Toluene | 108-88-3 | 890 |
| Total xylenes (ortho-, meta-, para-) | 1330-20-7 | 2170 |
6506.5 If the sample fails residual solvents and processing chemicals testing, the batch from which the sample was collected fails residual solvents and processing chemicals testing and shall be deemed adulterated.
SOURCE: Final Rulemaking published at 73 DCR 002136 (February 20, 2026).