It means the fingerprints or photo of someone who hopes to visit, study or work in Canada could be passed to Washington, which in turn might share them with another country to help verify the person's identity.
However, Canada would have to agree to the disclosure and could place restrictions or conditions on how the information is shared, says the treaty released Thursday.
The biometric sharing initiative — affecting nationals of 29 countries and one territory seeking visas to Canada — is part of a continental perimeter security deal reached last year.
The idea is to strengthen North American security while speeding the passage of goods and people across the 49th parallel.
Under the immigration agreement, biographic information — name, date of birth and gender of visa applicants and asylum claimants — will be shared by 2013. Biometric information, such as photos and fingerprints of select visa applicants, will be shared by 2014.
Information that Canada provides to the United States will be compared with various data banks to identify previously failed refugee claimants, deportees and those trying to enter under fraudulent names.
"If there is a positive hit, we will be notified of that," said Immigration Minister Jason Kenney.
"If the hit indicates something problematic — that perhaps that person had previously been deported by the United States, or that in fact the person has an alias — then we'll be able to more closely explore their real identity and whether they are admissible to Canada, or would constitute a security risk."
Washington will also check with Canada when someone applies to the U.S. for a visa or claims asylum.
The federal privacy commissioner's office has raised concerns that personal information provided by Canada could end up in countries that have a poor human rights record, endangering the applicant or their family.
Together at a ceremony Thursday to sign the treaty, Kenney and U.S. ambassador David Jacobson stressed that the data would be handled with due regard for privacy.
Jacobson noted the two countries had drafted overarching privacy principles to guide the various perimeter security initiatives.
"These are things that, quite frankly, are just as important in my country as they are in Canada," he said. "And we both feel very strongly about it."
Kenney said "rigorous privacy safeguards" will ensure that immigration information is shared in conformity with Canadian law, the Charter of Rights and the Privacy Act.
He called the treaty a "massive upgrade in Canada's immigration security" and emphasized that Canada will retain sovereignty over decisions as to who is allowed into the country.
The agreement says either country may disclose information received from the other to a domestic court for immigration purposes, as long is it has written consent from the providing country.
Canada or the U.S. may also share information with the government of a third country, with consent from the providing country, to verify someone's identity or to determine whether identity documents are genuine.
However, Canada and the U.S. commit to making "best efforts" to ensure no personal information is disclosed to a country from which the applicant has fled as a refugee, or a country in which the person's family members reside and might be endangered by such information exchanges.
The sharing of biometric information involves visa applicants to Canada from Afghanistan, Albania, Algeria, Bangladesh, Burma, Cambodia, Colombia, Democratic Republic of Congo, Egypt, Eritrea, Haiti, Iran, Iraq, Jamaica, Jordan, Laos, Lebanon, Libya, Nigeria, Pakistan, the Palestinian Authority, Saudi Arabia, Somalia, Sri Lanka, Sudan, South Sudan, Syria, Tunisia, Vietnam and Yemen.
Canada says the countries were chosen based on patterns including visa refusals, removal orders, refugee claims, and nationals arriving without proper documentation or under a false identity. Canadian foreign and trade policy objectives and tourism interest were also considered.
Note to readers: This is a corrected story. An earlier version said biometric information from refugee claimants would also be shared.
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