General Information: Mycobacterium MCS was isolated from soil in a wood preservative-contaminated land-treatment unit where remediation of polycyclic aromatic hydrocarbon (PAH) was occurring. This isolate mineralizes small- and large-ring PAHs, in contrast to other PAH-degrading microbes. Bioremediation of PAHs offers an attractive solution to pollution clean-up because it can occur on site and at relative little cost compared to alternatives. This isolate belongs to a fast-growing group of the mycobacterium genus that is defined as Gram-positive, acid-fast, pleomorphic, non-motile rods. Bioremediation of soils contaminated with wood preservatives containing polycyclic aromatic hydrocarbons (PAHs) is desired because of their toxic, mutagenic, and carcinogenic properties. Creosote wood preservative–contaminated soils at the Champion International Superfund Site in Libby, Montana currently undergo bioremediation in a prepared-bed land treatment unit (LTU) process.