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5. McLennan Hazard Registry

5.0  If You Work With Chemicals

All chemical users in the physics workplace must be familiar with their hazards, as well as the precautions and procedures for working safely with them. General requirements for such work includes, but not limited to:

Workplace Hazardous Materials Information System (WHMIS) training for those who work with chemicals and other hazardous materials;

  • Current MSDSs that are readily available to users:
  • Proper labeling, storage and handling of hazardous materials
  • Proper engineering controls such as general ventilation and local exhaust systems (e.g. fume hoods);
  • Use of proper personal protective equipment.
  • Proper procedures and equipment for chemical spills.

Chemical Inventory: Registration

Supervisory/Laboratory personnel should register their chemical inventory with the Physics H&S Committee, email Jo-Anne Wurster at . For further chemical safety information contact the Occupational Hygiene and Safety Services at (416)978-5943.

5.1  If You Work With Ionizing Radiation: Radioisotopes, X-Rays sources

Radioisotopes (alpha, beta, gamma or neutrons) and x-ray generating devices are strictly limited to authorized users only. The Ionizing Radiation Protection Program ensures appropriate controls to minimize potential exposure from both sealed and unsealed sources to people and the environment. Permit / registration systems limit the number, quantities, and locations of radioactive materials and radiation generating devices. Training courses are offered monthly to active users, awareness training is provided for those not using but potentially affected by exposure to ionizing radiation. Through regular audits, the Radiation Protection Service routinely monitors laboratories for compliance with University polices and regulations. This is reinforced by external audits and inspectors by the Canadian Nuclear Safety Commission, Ontario Ministry of Labour.

Ionizing Radioactive Sources Inventory: Registration

Supervisory/Laboratory personnel must register their radioactive sources with Radiation Protection Services (416) 978-2374 / 2028 / 6641 with inventory copies to the Physics H&S Committee, email Jo-Anne Wurster at

5.2  If You Work with Non-Ionizing Radiation: Electromagnetic Fields,  Lasers, Radiofrequency, Ultraviolet Sources

Non-ionizing radiation (i.e. lasers, electromagnetic fields, microwaves, radio frequency, static electric and magnetic fields, infrared, ultraviolet and etc.) must be kept below allowable levels. NIR safety courses are offered at least 6 times annually. Awareness training is provided for those potentially affected by such radiation. Through routine assessments and inspections, the Radiation Protection Service monitors non-ionizing radiation sources for compliance with University policy and regulations. All physics research lasers are monitored by the Laser Safety Committee.

Non Ionizing Radiation Sources: Laser & Laser Systems Registration, Electromagnetic Fields

Class 3b and 4 lasers must be registered by the Laser Safety Officer of the Radiation Protection Service, under authority of the U. of T. Laser Safety Committee. For further information about NIR education and inspection programs contact the Radiation Protection Services at (416) 978-2374 / 2028 / 6641.

5.3  If You Work With Liquid Cryogenic Materials

The general hazards associated with liquid cryogens are the following:

Oxygen deficiency caused by release of cryogenic liquids that have very high volume expansion can result in the rapid displacement of air and the potential for suffocation and death.

Over pressurization will develop in inadequately vented systems resulting in severe skin burns due to cold gas or liquid, or by expelling parts from a pressure leaks or bursts.

Cold stress at cryogenic temperatures weakens materials such as carbon steel, plastics and rubber resulting in spills or leakages.

Lastly, oxygen in surrounding air can condense when exposed to gases at liquid nitrogen temperature. Such oxygen enrichment may result in increased flammability and explosion hazards.

Cryogenic Liquids Inventory: Registration

Supervisory / Laboratory personnel should register their liquid cryogens with the Physics H&S Committee, email Jo-Anne Wurster at For further information, contact Robert Henderson, Physics Cryogenic Facility (416) 978-8510.