A gas attack in a home-supply store on one of the busiest shopping days of the year sickened scores of people in an incident that police called likely motivated by a commercial dispute or blackmail attempt.
Boxes containing timers wired to glass vials were discovered at the scene of the attack and three other stores in the same chain in Russia's second-largest city.
Seventy-eight people sought medical care: 66 were briefly hospitalized and sent home without any lasting ill effects, officials said. Police said that the store where the people were sickened had not yet opened for the day and all those affected were store employees or police, the ITAR-Tass news agency reported.
A police spokesman told The Associated Press that some customers had been sickened.
Officials with the Maksidom home-supply chain, which sells furnishings, home-repair material and other domestic articles, said they had received recent threats that sales would be disrupted around New Year's, when Russians traditionally give holiday gifts.
Most efforts to undermine competitors' sales in Russia's sharp-elbowed free market take the form of negative advertising or damaging rumors. Business-related violence nonetheless remains a feature of the cutthroat capitalism that enveloped Russia following the 1991 collapse of the Soviet Union.
"The first reaction is that it is one of the competitors of this store chain," St. Petersburg Gov. Valentina Matviyenko said in televised comments.
St. Petersburg police spokesman Vyacheslav Stepchenko said the gas appeared to be methyl mercaptan, a gas that smells like rotten cabbage and is both naturally occurring and manufactured for use in plastics and pesticides.
Chemist Lev Fyodorov, head of an environmental group called For Chemical Safety, said in an NTV television report that the gas rarely has long-lasting effects.
Employees at the branch where people were sickened told officials they heard a sharp noise, like a clap or pop, before people inside smelled a garlicky odor and began to feel ill. Police and security officers called to the scene found a mechanism with a timer attached to shattered ampules, Stepchenko said.
Patients complained of nausea and vomiting — along with chest pain and high blood pressure that probably resulted from nervousness, nurse Alexei Afanasyev said on NTV.
Stepchenko said that a custodian at another branch discovered a suspicious box before opening time and found ampules attached to wires and a timer inside. The woman inadvertently broke one of the ampules and noticed a repulsive smell but was not sickened, he said.
Boxes with glass containers attached to timers were found in two other stores by employees who carried them outside and covered them with buckets; police explosives experts defused them, Stepchenko said.