By the two verifiable frames that substitute for a license here. First, the OSHA bloodborne pathogens standard, 29 CFR 1910.1030: ask how crews are trained, protected, and equipped under it. Second, waste handling under TCEQ rules, 30 TAC Chapter 326: removed biohazard material should travel with registered transport and a manifest you receive a copy of. Add the ordinary checks: a written scope before work, photographs during it, and insurance of their own. A crew that answers all four plainly has given you everything a license would have told you, and more.
Prefer to talk later? Leave your details and an independent local pro will call you back. No charge to you, no obligation.
Brushy Creek Biohazard Cleanup is a free referral service. Submitting this form connects you with independent local contractors who provide the work.