NEW YORK -- The poison arrived in a plastic bottle from India bearing a simple label in English and Hindi. "Useful in flu and bodyache," it read. "Two tabs twice a day or as per physician's advice."
What it didn't say was that the herbal medicine, on sale at a store in Queens, contained 2,190 times the amount of mercury considered safe by the Institute of Medicine of the National Academies.
The tablets were among a variety of imported products seized by New York City health officials last year in immigrant-rich neighborhoods filled with exotic world goods -- some of which make it onto shelves without being evaluated by safety agencies like the Food and Drug Administration.
Other products that have been the subject of recent warnings include two pesticides banned in the U.S. because they are dangerous to children: an Asian roach killer nicknamed "Chinese Chalk" and a Latin American rat poison called "Tres Pasitos," or "three little steps," referring to how far a rat can walk before succumbing to the poison.
Last spring, authorities urged residents to stay away from unpasteurized Mexican cheese that had turned up at groceries in Brooklyn and Queens, saying it may contain a bacterium that causes tuberculosis.
A surge in foreign imports has made it increasingly challenging for U.S. food, health and customs officials to check the safety of all the products entering the country. Some 13.7 million imported products subject to FDA regulation entered the U.S. in fiscal 2005, compared to 7.9 million three years earlier, the agency said.
Almost all shipments are subject to automated screening, during which computers hunt cargo invoices for products with potential safety problems. But only about 75,000 shipments each year wind up being sampled and tested, said FDA spokesman Michael Herndon.
Customs officials get regular alerts on unsafe foods, cosmetics and medicines that should be barred, and inspectors seize items every week that don't meet U.S. standards, from contaminated fish from Asia, to Mexican cosmetics with unsafe color additives.
But the system is less effective when it comes to undocumented cargo that crosses the border daily in trucks, people's luggage or car trunks, by mail or inside larger shipments.
The flow of those undocumented products is small, but it can add up in the nation's immigrant gateways.
California, for example, has struggled for years with the sale of imported Mexican candies contaminated with lead.
Only a small percentage of the shipments crossing the border are detected, and immigrants who grew up on the treats have been skeptical of claims that they could be dangerous, said Leticia Ayala of the San Diego-based Environmental Health Coalition.
"What we found out was that the FDA didn't have the capacity to deal with this huge issue," Ayala said. "Most of the things that come across the border aren't being tested. So we can't rely on the federal government to protect us at the border."
A new California law now imposes a fine for selling contaminated candy, but authorities have yet to determine how much lead will trigger the penalty.
In New York, the city health department has cracked down on sales of skin creams and soaps from the Caribbean, Hong Kong and China that contained poisonous levels of mercury.
In January, it released a survey showing that the dangerous roach killer from Asia and rat poison from Latin America were still widely used in the city. A month earlier, a similar caution was issued about the Indian pills, Maha Sudarshan, and two other imported Indian herbal medicines with dangerous levels of mercury or lead.
Each had appeared on store shelves for some time before authorities realized they existed and could be a problem, health officials said.
"These are things we don't know enough about," said Nancy Clark, assistant commissioner of the city's Bureau of Environmental Disease Prevention, and a coordinator of the probe that led to the warning about the Indian medications.
Clark said the city only began actively looking for the medicines after seeing an article in the Journal of the American Medical Association linking some of the remedies to lead poisoning.
Inspectors got curious, went shopping and found the medicines on sale in Queens.
None of the shopkeepers knew that what they were selling could be dangerous, Clark said. All three of the Indian medicines are widely and legally sold in India, and the city doesn't have an easy way of tracking most products that could pose a health hazard.
"It is a little like finding a needle in a haystack," Clark said.