LAWYER PROFILE
Sinéad Oryszczuk

Sinéad Oryszczuk

UK 2026

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Ranked in 1 practice area

About

Provided by CMS

Practice Areas

Sinéad is an environment & product stewardship regulatory practice lead, based in CMS’s London office, and a core member of the firm’s international ESG group. Her prior experience includes head of the UK, Irish and EU environment practice of a multinational US law firm, and vice-chair and founding member of its international ESG practice. Her work spans a broad range of national and international legal areas and sectors, including environment, consumer/industrial products, chemicals, life sciences, technology, energy, food and real estate. She has built up particular experience in relation to chemicals and hazardous substances, novel technologies, innovative and borderline products, plastics, and product safety.

She has developed a unique contemporary and multi-disciplinary practice, in particular, assisting companies with fast-moving sustainability/ESG requirements and strategies, including implementation and audit of compliance programs, non-financial reporting and disclosures, green claims, pledges and commitments, and supply chain due diligence. She has also developed a solid but cutting edge ESG and sustainability M&A due diligence offering.

She advises on traditional environment issues, including contaminated land and remediation, warranties and indemnities, permitting, D&O liability, waste and FOIR/EIR matters. She regularly conducts specialist due diligence, including as outside counsel. She advises on energy efficiency/performance/audits, carbon trading/taxes/footprints, climate change, emissions, biodiversity, waste and water.

On product stewardship, Sinéad advises on matters throughout product lifecycle from design through to demonstration/promotion, repair, end of life, waste and returns and recalls; conducts due diligence on products (e.g. on chemicals and regulated substances, circular economy, WEEE, eco-design/-labelling, energy efficiency, product claims, packaging, batteries, conflict minerals and carbon footprints); and advises on supply chain and contractual arrangements.

She acts on contentious (criminal, civil and administrative) and non-contentious (regulatory, transactional) matters; has represented clients in high profile UK environment cases, as well as large group actions; and before specialist tribunals and the Court of Justice of the European Union. She regularly counsel companies through crisis management, including product recalls.

Sinéad has been ranked in Chambers for six years as a leading individual in environment, and was awarded EuroMoney’s Women in Business European/EMEA environment lawyer of the year in 2021 and 2022.

Professional Memberships

UK Environmental Law Association.

Chemicals Hazards Communications Society.

The British Association of Dangerous Goods Professionals.

Chambers Review

Provided by Chambers

Chambers Guide to the Legal Profession

Environment & Climate Change - London (Firms)

Band 4
Band 4

Individual Editorial
Sinéad Oryszczuk has a diverse practice that sees her advise clients on environmental issues across an array of sectors, including oil and gas, technology and pharmaceuticals. She is particularly well versed in prosecutions relating to pollution and environmental damage, with additional expertise in transactional advisory work.

Strengths

Provided by Chambers

  • I would recommend her to anyone dealing with complex regulatory matters.

    Environment & Climate ChangeChambers Guide to the Legal Profession
  • Sinéad is the best lawyer I have ever worked with. She has an incredible ability to provide practical solutions to incredibly complex issues.

    Environment & Climate ChangeChambers Guide to the Legal Profession
  • She goes above and beyond to gain a deep understanding of the industries she works with, giving clients the impression of working with a team member instead of an external adviser.

    Environment & Climate ChangeChambers Guide to the Legal Profession

Ranked Individuals at CMS (216)

London (Firms)

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