A stadium in St. Petersburg due to host a 2018 World Cup semifinal has been accused of breaking Russian rules on air quality.
The construction site for the 69,000-seat arena in the city had levels of formaldehyde and ammonia in the air above permissible standards when measured in October, according to a report from a St. Petersburg state health inspection agency.
The report, published by the St. Petersburg-based news site Fontanka, could not be independently verified by The Associated Press.
The company responsible for overseeing the construction, Metrostroy, did not dispute Fontanka's allegations, but blamed any air quality violations on a previous contractor.
It added levels were an "intermediate" measurement and "taken during the active phase of construction and do not reflect the picture when the stadium enters service" next month.
The stadium has endured repeated delays and cost increases in a decade-long construction project.
Last month, it was revealed that two stadiums for the 2018 World Cup -- in the cities of Volgograd and Nizhny Novgorod -- had also fallen behind schedule.