During a December 2025 visit to a Missouri social services facility, an industrial hygiene consultant with the Missouri On-Site Safety and Health Consultation Program detected a strong chemical odor. Trusting their instincts, the consultant investigated and quickly uncovered a potentially life-threatening situation.

An employee had attempted to unclog a drain using Liquid Fire, a sulfuric acid-based drain cleaner, and had inadvertently mixed it with bleach.

This dangerous combination can release both hydrogen sulfide and chlorine gas. Exposure to either gas can irritate the eyes and respiratory system, while higher concentrations can cause severe health effects, including serious injury or death.

Recognizing the immediate danger, the consultant acted without hesitation. They instructed facility staff to evacuate the building and contact the local fire department.

Their swift response helped ensure the situation remained under control:

• The facility was safely evacuated.
• The local fire department responded to the scene.
• Programs scheduled for the remainder of the day were canceled to protect staff and visitors.
• Firefighters used high-velocity fans to ventilate the building and reduce hazardous gas concentrations before the facility could be safely reoccupied.

This incident demonstrates how quickly routine maintenance tasks can become dangerous when incompatible chemicals are mixed. It also highlights the vital role that On-Site Consultation professionals play in recognizing hazards, taking decisive action, and protecting workers and the public.

In recognition of these lifesaving actions, the consultant received the 2025 Missouri State Team Member Award of Distinction.

The OSHA On-Site Consultation Program offers no-cost and confidential occupational safety and health services to small and medium-sized businesses in all 50 states, the District of Columbia, and several U.S. territories, with priority given to high-hazard worksites. Consultants from state agencies or universities work with employers to identify workplace hazards and how to fix them, provide advice for compliance with OSHA standards, train and educate workers, and assist in establishing and improving safety and health programs. On-Site Consultation services are separate from OSHA enforcement efforts. To locate the OSHA On-Site Consultation program nearest you, call 1-800-321-OSHA (6742) or visit www.osha.gov/consultation.