PSR for Industrial Hygiene and Worker Exposure to Hazardous Substances

HITE Engineering conducts Pre Start Health and Safety Reviews (PSRs) specifically focused on industrial hygiene and hazardous exposure risks, as required under Ontario’s Occupational Health and Safety Act (OHSA). These reviews are essential when a process, material, or environment may expose workers to regulated contaminants beyond legal limits, including designated substances like lead, silica, asbestos, isocyanates, and more.

Our team of professional engineers and industrial hygienists helps facilities proactively address exposure risks and remain compliant with O.Reg. 833 and O.Reg. 490/09.

When Is an Industrial Hygiene PSR Required?

A PSR is required when there is the possibility of worker exposure to substances exceeding any occupational exposure limits (OELs) outlined in the applicable Ontario regulations. These include airborne chemical hazards, fumes, vapours, particulates, or noise levels that can negatively impact worker health.

Common PSR Triggers Include:

Poor indoor air quality due to inadequate ventilation
Use of hazardous or designated substances in open or enclosed processes
Handling of solvents, resins, glues, coatings, or acids
Presence of fumes from welding, soldering, or combustion
Operations involving asbestos, lead, silica, benzene, or isocyanates
Exposure to noise above regulated levels

Scope of Our Hygiene Engineering Review

HITE’s comprehensive PSR for industrial hygiene includes both engineering evaluations and risk mitigation guidance, tailored to your facility’s specific exposure scenarios. We assess the following:

Ventilation system performance (local exhaust vs. dilution systems)
Airflow and make-up air calculations for adequate air changes per hour
Containment system design to minimize airborne spread
Review of engineering controls such as fume hoods, scrubbers, and enclosures
Effectiveness of PPE (respirators, face shields, protective clothing)
Comparison of worker exposure to threshold limits (TWA, STEL, PEL)
Review of exposure monitoring reports and data logging methods
Where needed, we’ll recommend improvements to both passive and active controls to bring your system into compliance.

Relevant Codes and Standards

Our PSR reviews are based on both provincial legislation and recognized industry standards, including:
O.Reg. 833 – Control of Exposure to Biological or Chemical Agents
O.Reg. 490/09 – Designated Substances
CSA Z94.4 – Selection, Use, and Care of Respirators
ACGIH TLVs & BEIs – Threshold Limit Values for chemical substances
WHMIS – Workplace Hazardous Materials Information System
O.Reg. 278/05 – For asbestos work assessment

We help you align internal safety practices with these codes, minimizing both health risks and regulatory penalties.

What We Need to Begin

In order to conduct a thorough and compliant PSR, we typically request the following documentation:
SDS (Safety Data Sheets) for all chemicals/substances used or produced
Exposure monitoring results (if available)
Diagrams or schematics of ventilation systems and control equipment
Photos or descriptions of process layouts and workstations
Maintenance logs for ventilation and containment systems
Any internal air sampling or hygiene audit reports

This information helps us understand the full risk profile and provide a realistic, code-based set of recommendations.

What You’ll Receive from HITE

Each PSR from HITE is tailored to the process and environment being reviewed. Our deliverables typically include:
A stamped Pre‑Start Health & Safety Review letter/report confirming compliance (or identifying gaps)
A summary of hazards based on exposure limits, control systems, and regulations
Engineering recommendations for risk mitigation (ventilation improvements, system redesigns, containment upgrades, etc.)
Optional follow-up support for implementing engineering controls or training programs

Why Choose HITE for Your Industrial Hygiene PSR?

With almost 30 years of experience in engineering safety compliance, HITE offers:
Dual-expertise teams: PSRs conducted by both professional engineers and certified industrial hygienists
Real-world knowledge across diverse industries including manufacturing, chemical processing, labs, and more
Practical, actionable solutions based on Ontario regulations and global standards
Fast turnaround times and ongoing support for updates, inspections, and regulatory inquiries

Protect Your People. Stay Compliant.

Exposure to harmful substances is one of the most silent and dangerous risks in Ontario workplaces. Whether you’re introducing a new process, modifying existing equipment, or facing a Ministry of Labour inspection, HITE Engineering can help you prepare with confidence.