The World Health Organization is warning that poor safety procedures at research laboratories could lead to a new global outbreak of Severe Acute Respiratory Syndrome, or SARS.

A spokesman for the Geneva-based United Nations health agency Monday said a big risk in the fight to keep SARS from reoccurring is that laboratory workers may get the disease and pass it on to others. Spokesman Dr. John MacKenzie said the agency has no idea how many labs are holding samples of the virus or whether they meet the necessary biosafety standards.

In Singapore last month, a 27-year-old medical researcher contracted the virus while working at a government lab. He eventually recovered.

SARS first broke out in southern China last November, and travelers spread it to neighboring Hong Kong as well as other parts of Asia and to Canada. More than eight thousand people were infected and more than 770 died.

The World Health Organization says it is particularly concerned about conditions under which the virus is being kept in Chinese labs.