DOT-COMPLIANT · ON-SITE EMPLOYER DRUG TESTING
Mobile Employer Drug Testing in Houston, Texas
We travel to your facility — refinery, petrochemical plant, port terminal, fleet yard, or job site — and administer federally compliant DOT and Non-DOT collections on-site. No clinic. No lost shifts.
Houston is the energy capital of the United States and one of the world's largest petrochemical and port logistics hubs. The Port of Houston — the nation's busiest port by foreign waterborne tonnage — handles over 200 million tons of cargo annually, with hundreds of FMCSA-regulated drayage carriers, PHMSA-regulated pipeline and terminal operators, and FRA-covered rail employees working within the port complex. ExxonMobil, Shell, LyondellBasell, Chevron Phillips Chemical, and Valero operate refineries and petrochemical plants along the Houston Ship Channel under PHMSA 49 CFR Part 199 pipeline and hazardous materials safety program requirements. Union Pacific and BNSF both operate major rail yards in the Houston area — UP's Englewood Yard and BNSF's Pearland Subdivision — with FRA-covered employees. United Airlines, Southwest Airlines, and multiple cargo carriers operate at George Bush Intercontinental (IAH) and William P. Hobby Airport (HOU) under FAA 14 CFR Part 120. For any employer in this market, the math on mobile testing is unambiguous: pulling a refinery contractor, a port terminal operator, or a CDL drayage driver to a clinic across Houston's freeway network adds hours to what should be a 30-minute collection.
OnSite Employer Testing coordinates mobile drug testing collections at your Houston-area facility, terminal, refinery, or job site. We do not operate a clinic. Review how it works or browse all locations we serve across the region.
Why Houston Employers Need Mobile Testing
Houston's DOT-regulated workforce spans every federal modal agency simultaneously. PHMSA-regulated pipeline and terminal operators along the Ship Channel run 24-hour operations where sending a covered employee off-site for a collection creates a staffing gap in a continuous-process environment. FMCSA-regulated port drayage carriers running between the Port of Houston and intermodal yards operate on tight gate-window schedules — a random test that pulls a driver out of the dispatch queue for two hours costs real money in missed gate cuts. FRA-covered Union Pacific and BNSF employees at Houston's classification yards work rotating shifts where post-accident testing has legally mandated time windows that a clinic across town cannot reliably meet.
The Houston petrochemical corridor — stretching from Pasadena to Texas City along the Ship Channel — is arguably the densest concentration of PHMSA-regulated employers in the United States. Contractors working on turnaround projects at multiple refinery clients in a single week often require pre-access drug testing from each host employer. Mobile collection at the contractor yard or the refinery gate eliminates the repeated clinic visits that turnaround season demands.
Program design and compliance obligations remain your responsibility under applicable law — we coordinate the collections.
Industries We Serve in Houston
Petrochemical, Refining, and Pipeline
ExxonMobil operates the Baytown Complex — one of the largest integrated petrochemical plants in the Western Hemisphere — along with refining and chemical manufacturing facilities throughout the Houston Ship Channel area. Shell's Deer Park Manufacturing Complex, LyondellBasell's Houston Refinery, Chevron Phillips Chemical, and Valero's Houston Refinery are among dozens of PHMSA-regulated operators whose covered employees — pipeline technicians, loading rack operators, and gas plant workers — must participate in anti-drug and alcohol misuse prevention programs under 49 CFR Part 199. We coordinate PHMSA-compliant energy and utilities collections at refinery gates, terminal operations buildings, and pipeline maintenance depots throughout the Ship Channel corridor.
Port of Houston and Maritime Logistics
The Port of Houston Authority oversees a 25-mile ship channel complex with hundreds of industrial and terminal tenants. FMCSA-regulated drayage carriers moving containers between the port's Barbours Cut and Bayport terminals and regional intermodal yards operate on strict gate schedules. Terminal tractor operators, yard hostlers, and over-the-road CDL drivers all require pre-employment and random testing under FMCSA 49 CFR Part 382. We coordinate logistics and transportation collections at port terminals, container yards, and carrier dispatch facilities throughout the Houston port complex.
Rail Operations
Union Pacific operates Englewood Yard in Houston — one of UP's largest classification yards in the southern United States. BNSF operates through the Houston region via the Pearland Subdivision with connections to the port and to the broader Texas rail network. FRA 49 CFR Part 219 requires covered railroad employees — engineers, conductors, maintenance-of-way workers, and signal employees — to participate in random, post-accident, and reasonable suspicion programs. We coordinate FRA-compliant DOT drug testing collections at rail yards, engine houses, and crew reporting facilities throughout Harris County.
Aviation — IAH and HOU
George Bush Intercontinental Airport (IAH) is United Airlines' largest hub and a major cargo gateway for FedEx, UPS, and DHL. William P. Hobby Airport (HOU) is Southwest Airlines' largest hub by operations. Both airports host FAA 14 CFR Part 120 safety-sensitive employees — flight crew, ground handlers, fuelers, aircraft maintenance technicians — across dozens of carriers and ground service providers. We coordinate FAA-compliant aviation and airline employer collections at both airports and at employer facilities in the airport business corridors.
Construction and Downstream Contractor Workforce
Houston's petrochemical turnaround and capital project construction sector employs tens of thousands of craft workers annually. General contractors and specialty subcontractors working at ExxonMobil Baytown, Shell Deer Park, and LyondellBasell facilities maintain Non-DOT company-policy programs as a condition of site access, often requiring pre-access testing within a short window before mobilization. Construction employers with CDL crane operators and heavy equipment operators also require FMCSA DOT programs. We coordinate both DOT and Non-DOT workplace drug testing for the turnaround and construction workforce throughout Harris County and surrounding petrochemical communities.
Testing Services Available in Houston
We coordinate the following collections for Houston-area employers:
DOT drug testing collections (FMCSA, FRA, FAA, FTA, PHMSA)
- Pre-employment drug and alcohol testing
- Reasonable suspicion and return-to-duty testing
Breath alcohol testing (BAT certified)
- Oral fluid drug testing
Mobile and on-site collections at your facility, yard, or job site
Communities We Serve Near Houston
In addition to Houston proper, we serve employers throughout Harris County and the broader metro including Pasadena, Deer Park, La Porte, Baytown, Texas City, Galveston, Sugar Land, Pearland, Katy, and The Woodlands.
Employers along the Houston Ship Channel, in the Barbours Cut and Bayport terminal complex, at Englewood Yard, and throughout the petrochemical corridor from Pasadena to Texas City are within our service range. Use our instant quote calculator to scope your collection or visit our service areas page.
Questions from employers in this region
ExxonMobil Baytown requires pre-access drug testing for turnaround contractors. Can you coordinate multiple pre-access collections in the same week at the refinery gate or contractor yard?
Yes. High-volume pre-access collections for turnaround mobilizations are a core use case for mobile testing. We coordinate collections at your contractor yard, the refinery gate staging area, or any employer-designated location. For multi-day mobilizations, we schedule collection windows that match your workforce reporting schedule.
Union Pacific's Englewood Yard runs around the clock. Can you respond to a post-accident FRA testing event at the yard at any hour?
FRA post-accident testing has mandatory time windows — typically within 4 hours for alcohol and 32 hours for drugs following a qualifying event. We coordinate emergency mobile collections on an expedited basis. For Englewood Yard and other 24-hour rail operations in the Houston area, we recommend establishing a contact protocol in advance so a post-accident response can be initiated immediately.
We operate a drayage fleet at the Port of Houston's Barbours Cut terminal. How does random testing work when drivers are only at our facility briefly before gate check-in?
We coordinate random collections at your dispatch facility or driver check-in area before drivers proceed to the gate. Random selection notification is handled through your designated employer representative; we schedule the collection to fit the dispatch window. Drivers are tested at your facility — not routed to a clinic on the other side of the Ship Channel.
Shell's Deer Park Manufacturing Complex uses multiple staffing contractors. Can you serve the staffing agencies that provide workers to the site, not just Shell directly?
Yes. Staffing agencies and labor contractors whose employees work at petrochemical facilities are responsible for their employees' DOT or Non-DOT testing programs. We coordinate collections for staffing agencies at their office, at the contractor yard, or at a pre-access staging area designated by the host facility. Program design and compliance obligations remain your responsibility under applicable law — we coordinate the collections.
Core programs: Mobile & on-site drug testing, DOT drug testing, Non-DOT drug testing, Post-accident testing, Reasonable suspicion testing, Random testing programs, Breath alcohol testing. Planning: how it works, instant quote calculator, all locations. Industries: employer industries we support. Long-form answers: Employer drug testing FAQ. Quick questions: Contact us.
For how we think about regions and feasibility, see service areas.
Nationally coordinated collection support
OnSite Employer Testing is headquartered in Illinois and coordinates mobile and on-site employer testing across selected regions and employer locations—including through partner collectors when your program, timing, and geography allow. Availability depends on location, timing, test type, site access, collector availability, and scheduling needs.
Scope collections for your Houston-area operation
Share your facility address, expected donor count, test reason, and DOT or non-DOT status — we confirm what is workable and send a written proposal.