Workers at a Fife refinery withdrew their labour over safety concerns prompting calls for an investigation, a union has said.

ExxonMobil’s Mossmorran refinery in Cowdenbeath will be subject to inquiries from the Health and Safety Executive after industrial action on Tuesday August 15.

Unite claimed about 200 workers withdrew their labour at the petrochemical plant – a legal right under the Employment Rights Act – due to safety concerns.

However, ExxonMobil said less than 100 workers walked out of the refinery and that many Unite members did not get involved.

And the company said that the Fife Ethylene Plant “operates in full compliance with approved site safety standards and procedures”.

Unite claimed the workers objected to “health and safety warning signals and procedures not being in full working operation across the plant” and a lack of procedures put in place to protect them.

The union claimed ExxonMobil and contractors Altrad, Bilfinger and Kaefer, failed in a “legal duty” to protect and pay workers.

Unite said it received reports from workers citing repeated examples over a year that alarm systems were not working in areas at the petrochemical plant and workers not being notified – which is legally required in the event of any leakages, blasts or exposure to hazardous materials and chemicals.

It also alleged that workers were having pay withheld, contrary to employment laws which say workers have the “right” to withdraw from, and to refuse to return to a workplace that is unsafe, without being subject to loss of wages.

Unite general secretary Sharon Graham said: “Unite will robustly defend the legal right of our members to withdraw their labour over health and safety concerns at ExxonMobil’s Mossmorran plant.

“It is completely unacceptable that the company and the various contractors on site are refusing to pay our members their wages.

“This is a legal duty and not open to interpretation.

“Our members will be receiving their union’s unflinching support.”

Unite members at ExxonMobil’s plant are employed on construction engineering maintenance contracts and they are split between different contractors at the plant: Altrad, Bilfinger, and Kaefer.

Unite is further calling on the Health and Safety Executive (HSE) to investigate immediately due to the seriousness of the claims.

The union claimed there have been various recorded incidents at the plant over safety, the risk of pollution and environmental damage.

Bob Macgregor, Unite industrial officer, added: “Unite’s members working for Altrad, Bilfinger, and Kaefer at the Mossmorran plant are rightly furious at potentially being exposed to dangerous chemicals due to failings in the plant’s safety procedures.

“To add insult to injury, ExxonMobil and the contractors are refusing to pay the wages of the workers following the withdrawal of labour on health and safety grounds.

“This is not an isolated incident, these safety breaches and failings have been ongoing for around a year and nothing to date has been resolved.

“That’s why Unite is calling for the Health and Safety Executive to urgently intervene due to the seriousness of the claims, and the chequered history of the plant.”

An ExxonMobil spokesperson said: “We are aware of unofficial action instigated by a small number of individuals employed by contracting companies on our site.

“There is no impact on our operations, which continue as normal.

“Fife Ethylene Plant operates in full compliance with approved site safety standards and procedures.”

A HSE spokesperson said: “We are aware of safety-related concerns being raised by union and employee representatives onsite.

“We are now making inquiries with the site operator.”

A spokesperson for Kaefer Limited said: “We confirm that Kaefer employees contracted to work at the ExxonMobil FEP site have been involved with unofficial and sitewide strike action this week.

“We support constructive dialogue between Unite the Union, GMB, and all impacted organisations to reach a mutually acceptable resolution.

“The safety of our employees is always our highest priority.”

Altrad and Bilfinger have been approached for comment.