Urea-formaldehyde foam insulation (UFFI) was developed in Europe in the 1950’s as in improved means of insulating difficult to reach cavities in house walls. It is typically made at a construction site from a mixture of urea-formaldehyde resin, a foaming agent and compressed air. When the mixture is injected into the wall, urea and formaldehyde unite and “cure” into an insulating foam plastic. During the 1970’s when concerns about energy efficiency lead to efforts to improve home insulation in Canada, UFFI became an important insulation product for existing houses. Most installations occurred between 1977 and its ban in Canada in 1980.