O'Neill Associates

(807) 344-5227

The OA Team

Founded in 2018, O’Neill Associates brings together a hand-picked team of like-minded lawyers and support staff who find creative solutions to each client’s unique problems.

Garth O’Neill

Law Society of Ontario Certified Specialist (Labour Law)

Called to the Bar in 1991

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Garth O’Neill is one of the most well known and respected labour and employment lawyers in Northwestern Ontario and is recognized by the Law Society of Ontario as a Certified Specialist in Labour Law. Since 1991, Garth has advised many leading industrial and public-sector organizations throughout Northwestern Ontario on labour and employment law issues. He regularly represents management in contract negotiations and appears as counsel before the Labour Relations Board and Grievance Arbitrators, as well as at the Workplace Safety and Insurance Board (WSIB), Employment Standards, and Occupational Health and Safety proceedings.  Garth serves larger institutions as well as smaller companies and service-sector clients, and represents individuals in disputes with their employers.

Garth has completed comprehensive advanced training in facilitative mediation through the Stitt, Feld, Handy Group in Toronto, and adds ADR/mediation to the long list of services he offers his clients.

Garth believes in building strong, long-term relationships with clients. He regularly travels throughout Northern Ontario to serve his clients in their communities. Garth takes the opportunity, wherever possible, to commit to speaking engagements on workplace planning and management training for many of his clients. He often appears as a speaker and panellist at labour and employment law seminars in Thunder Bay and the region.

Community Involvement

  • Chancellor, Anglican Diocese of Algoma
  • Frequent Speaker and contributor at Human Resource conferences and events
  • Member, Private Pension Committee


    • LLB, Queen’s University, 1989

Hayley Yorke

Associate Lawyer

Called to the Bar in 2018

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Hayley Yorke understands that labour and employment law solutions must be as diverse as the people they impact. Hayley provides practical and proactive advice to clients to navigate difficult situations or avoid litigation before it happens. She represents management in all aspects of labour relations including matters at Grievance Arbitration and before the Labour Relations Board. Hayley also handles matters before the Workplace Safety and Insurance Board and its Appeals Tribunal, as well as the Human Rights Tribunal. Hayley brings an eclectic range of work experience to her legal perspective; from her work at Disney World to housekeeping, her experiences ensure her advice is well-rounded and effective. She knows that the law of work should work for her clients and is committed to ensuring that it does.

Hayley believes volunteer work is an integral part of a lawyer’s commitment to their community. Hayley has volunteered her time for the YWCA, the Humane Society, and the Dew Drop Inn. Her current volunteer work focuses on diversity and inclusion in Northern Ontario. Her work with LEAF Thunder Bay aims to advance substantive equality for all women, girls, trans, and non-binary people.

Hayley’s Corgis, Mozzarella and Gouda, have become our unofficial mascots – at least they think so!

Community Involvement

  • President, LEAF Thunder Bay (Women’s Legal Education and Action Fund)
  • Committee Member, Braiding Diversity Into Justice Thunder Bay
  • Volunteer Lawyer, the Indigenous Human Rights Clinic Thunder Bay


  • JD, Lakehead University, Bora Laskin Faculty of Law, 2018.

Erin Hansen

Associate Lawyer

Called to the Bar in 2020

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Erin joined O’Neill Associates in May 2019 as a Summer Student, and returned as a Placement Student in September 2019 before finally joining the team as an Associate Lawyer in November 2020. Erin has always had her sights set on working as a labour and employment lawyer. Erin graduated from the Bora Laskin Faculty of Law where she was awarded a number of prestigious scholarships and awards for her academic achievements, including First Class Standing, Dean’s Honour Roll Prizes for ranking second in her class, and the Course Prize for the highest mark in Evidence Law. During law school, Erin was heavily involved with the school’s Labour Law Association, holding both Vice President and President roles. Before completing her law degree, Erin completed a Bachelor of Commerce in Business Management with a Major in Law and Business where she focused her studies on workplace law and economics. Erin was also a competitive member of the debate team for all of her academic career leading up to law school, taking home her first debate trophy at only 12 years old.

Growing up in Kenora and Thunder Bay, Erin understands what it’s like to live and work in Northwestern Ontario. Prior to law school, Erin worked full-time for a not-for-profit organization that was devoted to studying and improving the labour market conditions in Northwestern Ontario. In that capacity, Erin travelled to communities throughout the area to speak with business owners and employees about the difficulties they faced in working and running businesses in the North. Erin’s personal, professional and academic history have all helped her develop a deeper understanding of employment and human rights issues faced by individuals and employers in the region. She puts this background to good use in her legal career.

In her spare time, Erin makes the most of the outdoors, even in the face of Thunder Bay’s infamous six (or more) months of winter. Erin’s hobbies include downhill and cross-country skiing, snowshoeing, sailing, and hiking. She also devotes much of her time to volunteering with local animal rescues and is usually ready at any time to show you pictures of her latest foster animals.

Community Involvement

  • Volunteer, Paws for Love Dog Rescue
  • Volunteer, Murillo Mutts Respite Refuge


  • JD, Lakehead University, Bora Laskin Faculty of Law, 2020
  • French Language Diploma, Level B2 (Diplôme d’études en langue), 2014

Natalie Gerry

Associate Lawyer

Called to the Bar in 2017

  • Human Resources, Labour Relations & Employment Law
  • Civil Litigation (including both Plaintiff and Defence work in wrongful termination and constructive dismissal claims)
  • Administrative Law (including claims before the Human Rights Tribunal of Ontario)

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Natalie has a broad range of civil litigation experience, with a particular interest in wrongful dismissal and human rights law. She appears regularly before the Superior Court of Justice and various administrative tribunals.

Natalie articled and joined a local law firm as a litigation associate in 2017. She recently joined O’Neill Associates as one of our Associate Lawyers. Natalie enjoys problem solving and helping her clients achieve successful litigation outcomes.

Natalie is from Sudbury originally. She pursued her Honours BA at the University of Toronto (Trinity College) and attended Western University for her Master’s. She returned to Northern Ontario for law school and was awarded her law degree in 2016 from Lakehead’s Bora Laskin Faculty of Law.

Natalie has a keen interest in feminist issues. In addition to her legal work, Natalie is a founding member of the Thunder Bay Branch of the Women’s Legal Education and Action Fund (LEAF), an organization dedicated to advancing substantive equality rights for women and girls through litigation, law reform, and public education. Natalie is a board member of the Thunder Bay Sexual Abuse Centre. She has also acted an adjudicator with Lakehead University’s Sexual and Gender-based Violence Panel.

In her spare time, Natalie enjoys practicing yoga and cross-country skiing.

Community Involvement

  • Board Member, Thunder Bay Sexual Abuse Centre
  • Board Member, Thunder Bay Law Association
  • Board Member, Women’s Legal Education and Action Fund


  • JD, Lakehead University, Bora Laskin Faculty of Law, 2016
  • Master’s, Western University
  • Honours Bachelor of Arts, University of Toronto

Andrew Mawdryk

Associate Lawyer

Called to the Bar in 2022

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Andrew Mawdryk is a graduate of the Bora Laskin Faculty of Law where he was actively involved in several clubs, holding the position of Co-President of the Human Rights Law Club during the 2020-2021 academic year, President of the Sports Law Club during the 2021-2022 academic year, and President of the Labour and Employment Law Association during the 2022 winter semester. In the classroom, Andrew was awarded the Course Prize for the highest mark in Wills and Estates Law.

Prior to law school, Andrew completed an honours in political science and a major in geography at McGill University. Andrew’s interest in labour and employment law began years ago when he spent his summers in his home province of Quebec, working as a Camp Director at a non-profit camp for underprivileged children – something he continues to do when time allows. Among his many duties, he handled all employment and human resources matters for a team of over 75 staff members.

Andrew joined O’Neill Associates in May 2021 as a Summer Student, and returned as a Placement Student and then for his second summer before joining O’Neill Associates in November 2022 as an Associate Lawyer.

In his spare time, Andrew enjoys camping across Northwestern Ontario during the summer months, and playing hockey throughout the winter.

Community Involvement

  • Board Member, Lakehead Social Planning Council
  • Volunteer, PRO kids


  • JD, Lakehead University, Bora Laskin Faculty of Law, 2022
  • BA, Honours in Political Science & Geography, McGill University, 2019

Christopher (“Chris”) Gash

Associate Lawyer

Called to the Bar in 2018

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Christopher is the newest addition to the team at O’Neill Associates. Prior to joining the firm in June of 2023, Christopher practiced general litigation, including litigation involving wrongful termination and constructive dismissal, and brings a broad range of knowledge in many different areas of law which often intersect with challenges facing clients in the Human Resources, Labour and Employment context. Christopher is a pragmatic problem-solver who aims to provide real world and timely solutions to his clients amidst a complex and ever-changing legal landscape.

Born and raised in Thunder Bay, Christopher enjoyed a successful career in the automotive industry in both sales and management with local dealerships for over 10 years prior to attending Lakehead University in 2009. Christopher obtained a Master’s Degree in Sociology with specialization in Gerontology in 2014 from Lakehead University and thereafter graduated from Lakehead University’s Bora Laskin Faculty of Law with first-class standing in 2018.

During his time in the automotive industry and over the course of his studies at Lakehead University, Christopher was involved as a volunteer in the care and services for seniors’ sector.

Christopher takes great pride in having completed his Master’s Degree via the thesis stream by way of a research study funded by the Social Sciences and Humanities Research Council involving seniors living with dementia in long-term care homes in Northwestern Ontario.

 Notwithstanding Christopher’s professional and academic achievements, Christopher’s greatest source of pride comes from his family, being the father of five. When he is not assisting clients with their legal needs, he can be found taking advantage of every moment he can to spend time with his family and friends in Northwestern Ontario.

In addition to spending time with his family and friends, Christopher enjoys golfing, fishing, hunting, and playing guitar.

Community Involvement

  • Volunteer, City of Thunder Bay Long Term Care & Senior Services


  • JD, Lakehead University, Bora Laskin Faculty of Law, 2018

Rosanne Stasiewicz

Executive Assistant/Marketing Coordinator

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Rosanne Stasiewicz at one time last year decided to retire from O’Neill Associates, only to learn that she missed the clients and her co-workers. She comes into the office once a week to continue marketing duties for the firm, and basically parachutes into any job where she is needed.

In her spare time, Rosanne enjoys reading, weight lifting, and especially spending time with her 2 grandchildren. Rosanne herself has been active in the community. She is on the Fundraising Committee for a charity she deeply believes in – PRO Kids. Rosanne was proudly one of the founding members of “Chairs for Chairity”, in support of the Shelter House Thunder Bay, and has also participated and/or fundraised for many Thunder Bay events – most recently the Salvation Army Christmas Kettle.

Rosanne is known for her wicked sense of humour (a product of her environment, she claims) and her creativity in finding resourceful solutions to any problem. Her professionalism, dedication, and approachability are the embodiment of O’Neill Associates.

Karen Mercier

Law Clerk

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Karen Mercier brings with her nearly 40 years of legal experience, having worked in many areas of law including Labour and Employment, and Litigation matters. She is an IT, organizational and legal procedures guru, having trained countless junior and not-so-junior staff during her career. Her get-it-done approach ensures effective file and document management, and gives our clients great comfort in knowing their matters are well in-hand. Her professionalism and calming demeanour assists in the most stressful situations.

Legal worker by day, artist by night, Karen is a talented painter lending her time to various fundraising events. She enjoys working with acrylics as well as yarn art. A woman with many interests, her next goal will be mastering her electric ukulele.

Karen enjoys spending time with her family at their cottage on Lake Superior. With our office just a short walk up from Marina Park, watch out for her travelling to the office by boat, or paddle board, next summer. With Karen, you just never know!

Donna Kinnunen

Office Administrator

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Donna has more than thirty years’ experience in law firm administration. If an issue has arisen in the complex world of legal services, she has encountered it – and conquered it. Every now and then, you meet someone who has found a solution before you knew you had a problem. Donna is that person. With a calm demeanour and a wry sense of humour, Donna’s presence in the office brings still waters, and clients can be comforted in knowing she’s “on it”.

Donna is responsible for overseeing our administration functions in the office. She excels in customer service and is the friendly face who greets you when you arrive. Her administrative role includes various tasks such as file support, accounts payable, accounts receivable, data entry, payroll, and banking services.

With a passion for all that’s Northwestern Ontario, Donna particularly enjoys taking time to savour the tranquility of the outdoors. She has a zest for life like no other, and can always find reason to add a theme to the occasion. Her true passions in life are family and the time spent together, and community involvement.

Donna is a long-time supporter of local charitable organizations, and has left her mark on community events such as the Dragon Boat Festival, Corporate Relay, Chairs for Charity, Big Bike and the United Way, to name a few.

Cheryl Mohring

Law Clerk

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Cheryl brings over 37 years of experience to the OA team having an in-depth knowledge and background of the law, practice and procedures dedicated to serving clients. She obtained her Law Clerk designation from the Law Clerk Institute of Ontario, and has worked in all areas of practice including litigation, with the last 16 years dedicated to labour and employment law.

Chery’s experience includes drafting, policy review, conducting research, and preparing files for mediations, arbitrations and collective bargaining. She has been instrumental in the preparation of cases for hearings before the Workplace Safety and Insurance Board (WSIB), the Workplace Safety and Insurance Appeals Tribunal (WSIAT), the Ontario Labour Relations Board, the Ontario Human Rights Tribunal, the Canadian Human Rights Tribunal, the Canada Industrial Relations Board, and the courts at both provincial and federal levels.

Cheryl’s calm and approachable demeanour give clients the confidence that even the most complex matters will be handled professionally and with sensitivity.

Cheryl believes in giving back to the community, and has been involved in events such as the CIBC Run for the Cure and the Salvation Army Kettle Campaign. She is a member of the Canadian Red Cross, Zone Watch Program (Thunder Bay Police Service), and has actively organized and prepared meals at the Shelter House.

In her spare time, Cheryl enjoys entertaining, long walks, hiking and spending time with family and friends.

Christy Mohring

Legal Assistant

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Christy Mohring is the latest addition to the O’Neill Associates law firm. Born and raised in Thunder Bay, Christy graduated from Lakehead University with her HBA, and a major in Psychology. Through previous employment, she now has a background in mental health/addictions, and has worked closely with vulnerable people and populations.

Christy is bilingual, and enjoys working with a team, always embracing new learning
opportunities. She brings a positive energy to our firm.

Always up for an outdoor adventure, Christy can be found hiking, trapping, plucking geese in her spare time, or generally looking for new experiences. She recently picked up baking as a pastime, and the office has greatly benefited from her many delicious “experiments.” Christy believes in community participation and has volunteered in the past with the Red Cross, Elizabeth Frye Society, Shelter House, and with CIBC’s “Run for the Cure.”


Hayley Yorke and her partner Graham Killin added an adorable red and white Corgi puppy to their household in 2018 which they promptly named Mozzarella (or Ozzy for short). He’s sweet and intelligent, somewhat anxious at times especially when his sister misbehaves, and OA has happily adopted him as one of our mascots. Ozzy loves walks in the park, sunsets and of course if any steak drops on the floor, well let’s just say it will be claimed, and claimed quickly. Ozzy really does not need any introduction as he already has a huge following on Instagram. Can’t keep the pup-arazzi away!


Well, Hayley and Graham could not stop at just one adorable puppy so along came Gouda, a long-haired tri-coloured Corgi, in 2020 to add to their family.  Gouda is the complete opposite of her brother Ozzy – she’s the wild child, and goes to the beat of her own drum.  She is fond of chewing on poor Ozzy’s ears to entice a chase – something OA has affectionately labelled the “zoomies” where they pursue each other at a frenzied pace.  Gouda likes to listen to vinyl, drives a Subaru, destroys dog toys just because, and pretends she is hard of hearing, especially when she is being naughty.  You wouldn’t let her babysit your kids…