Hundreds of workers at a Huddersfield company face the prospect of major changes to their pension scheme.

A 60-day consultation period is underway between bosses at agri-chemicals business Syngenta and 248 employees at the Leeds Road site who are members of the firm’s defined benefit pension scheme.

The talks centre on proposals to base the employees’ pensions on their pensionable pay at March 1, 2015 – no matter how many more years they may be employed by the company or how their pay may increase over that period.

Under the proposals, employees in the scheme could continue to make their own contributions to build up a pension, but it would not grow in line with future pay.

The company stressed that deferred and retired members of the scheme were not affected.

Syngenta said the changes were needed to tackle a pensions deficit running into hundreds of millions of pounds and ensure the scheme remained sustainable in the long term. It said the scheme would still have “clear benefits” to employees and compare favourably with many other pension schemes.

A statement by the company said: “The costs associated with defined benefit pensions have risen dramatically in recent years, due to changing regulatory requirements, low interest rates and the fact that we are all living longer.

“In order to ensure the sustainability of our defined benefit scheme over the long term, Syngenta is consulting on a proposed change whereby any future pay increases would not be taken into account when calculating the final pension benefit.

“Those employees who are still part of this scheme will receive a defined benefit pension although it will not grow in future in line with pay. Nevertheless, it remains a very significant pension benefit compared to what is generally available to UK workers.”

The statement said: “This decision has not been taken lightly and we know how important this scheme is to those of our employees who benefit from it. We therefore look forward to receiving their feedback on our proposal before a final decision is taken on how to ensure the long term sustainability of this scheme.”

The spokesman said Syngenta was committed to its UK sites, including its Deighton works, which has 362 employees manufacturing crop protection products which are exported around the world.

He said: “We are committed to our UK sites and to our employees in the UK in making sure we have good benefits, good capital investment and a good future.”