Hurricane Maria has disrupted packaging group Essentra's operations in Puerto Rico causing the British firm to warn it would lose up to £750,000 a week.
The FTSE 250 group, which makes cigarette filters and other products, said its two health and personal care packaging sites have not been operational since Tuesday.
There are significant barriers to resuming activity, including the circumstances of Essentra's 345 employees in Puerto Rico, the availability of power and the ongoing disruption to general infrastructure, the company said.
Hurricane Maria knocked out water and power services and engineers have said it could take months to be restored.
"It is not currently possible to confirm the timing that normal output levels will be resumed; however, this is unlikely to be in the immediate future," Essentra said.
The company put the financial cost at around £500,000 to £750,000 per week but said a "significant" part of that is expected to be recovered through insurance.
Essentra added its Houston, Florida and Puerto Rico operations had experienced minor disruptions by hurricanes Harvey and Irma, and it estimated its pre-Maria profit to take a hit of £500,000 to £1m.
"With communications in Puerto Rico remaining sporadic, our ongoing priority is confirming the safety of all our employees and on providing them with whatever assistance we can, including the shipment of emergency provisions as soon as ports and the airport reopen," said Paul Forman, chief executive of Essentra.
"Given the exceptional nature of Hurricane Maria and the current level of uncertainty regarding its ongoing impact, the company is clearly continuing to closely monitor the situation in Puerto Rico and will provide an update in our next trading statement, or when we have greater clarity if earlier."
Shares in the company were down 1.09 per cent at 500.5p in afternoon trading.