SHIELD SOURCE INCORPORATED was founded in 1986 to manufacture and distribute tritium GTLS sources and self-luminous safety signs throughout Canada, the United States and other international markets.  The headquarters is located at the Peterborough Municipal Airport.  The company specializes in products of maximum light output for long life and low maintenance applications such as emergency exit signs and safety pathway markers.  Licenses have been granted from the Canadian Nuclear Safety Commission and the Ontario Ministry of Environment to cover its present operations, including manufacture and testing of various lighting systems.  The company also maintains offices in the United States for warehousing, sales and distribution.

Under a technology transfer agreement, SSI has purchased rights to certain products and processes developed by Safety Light Corporation which has been in the business for over 40 years.

At present, the company is manufacturing a line of commercial emergency safety signs for sale in Canada, the United States and other international markets.