After nine of its staff have been diagnosed with coronavirus, Asos said there was "no evidence" they caught it at work.
It also said strict social distancing measures and safety procedures have been put in place throughout the outbreak of the deadly virus.
A spokesman for Asos, responding to rumours on social media, told YorkshireLive : "As this global crisis progresses, it’s clear no workplace is insusceptible to coronavirus and, like many others, we, too, have been impacted, with a small number of confirmed cases.
"That said, there is no evidence to suggest these cases were contracted in the warehouse and the percentage of our team impacted is significantly lower than the national average and for that of the Barnsley Metropolitan area, within which our site is based.
"Of the nine people affected, close to half had not been on site for more than two weeks before testing positive for the virus, and all have self-isolated at home, in line with government guidance.
"We remain in contact with them and wish them well with their recoveries.
"Given the warehouse’s size and scale, its level of automation and the extra, industry-leading health and safety measures we have put in place since the start of the pandemic, it remains a safe place to work.
"We and XPO Logistics, which manages the site on our behalf, are monitoring the situation closely and have taken further precautionary measures.
"This includes contact tracing – asking anyone who was in contact with the individual to monitor themselves for symptoms - and ensuring any areas where the individuals have been are cleaned as part of an enhanced hygiene programme.
"As the health and wellbeing of our staff is our number one priority, we are maintaining our social distancing protocols, which in many areas exceed the latest Government guidelines issued this week, and communicating regularly with staff, the recognised union, Community, and the Environmental Health Officer, who has visited the site and verified our approach numerous times over the past six weeks.
"Since these cases came to light, we have proactively contacted the local Environmental Health office to provide a detailed briefing on the situation.”
A spokesperson for the trade union Community said: "As the recognised trade union at XPO we are in regular contact with senior management and our on-site union reps will be meeting management on a daily basis to monitor the situation and the impact of the extensive safety measures that have been agreed and implemented.
"We will continue to review all necessary steps available to protect workers on site."
